jcode + GPT-5.5 on utf16-transcode

{"goals": [{"end_to_end_ownership": null, "feedback_loop": "Repeated ./grade runs report deterministic correctness and callgrind score in scores.jsonl.", "group": "utf16-transcode", "hill_climbability": 95, "objective": "Optimize submission/solve.c while preserving correctness on all grader inputs.", "user_intention": "Achieve the highest benchmark score possible for utf16-transcode.", "user_intention_alignment": 100}], "intent": "Plan optimization workflow", "todos": [{"completion_confidence": null, "confidence": 95, "content": "Read spec.md and baseline implementation", "group": "utf16-transcode", "id": "read-spec", "priority": "high", "status": "in_progress"}, {"completion_confidence": null, "confidence": 90, "content": "Run baseline grade to confirm environment and score", "group": "utf16-transcode", "id": "baseline-grade", "priority": "high", "status": "pending"}, {"completion_confidence": null, "confidence": 85, "content": "Implement and iterate optimizations in submission/solve.c", "group": "utf16-transcode", "id": "optimize", "priority": "high", "status": "pending"}, {"completion_confidence": null, "confidence": 90, "content": "Validate final solution with ./grade and report final score", "group": "utf16-transcode", "id": "final-grade", "priority": "high", "status": "pending"}]}

[ { "content": "Read spec.md and baseline implementation", "status": "in_progress", "priority": "high", "id": "read-spec", "group": "utf16-transcode", "confidence": 95, "confidence_history": [ 95 ] }, { "content": "Run baseline grade to confirm environment and score", "status": "pending", "priority": "high", "id": "baseline-grade", "group": "utf16-transcode", "confidence": 90, "confidence_history": [ 90 ] }, { "content": "Implement and iterate optimizations in submission/solve.c", "status": "pending", "priority": "high", "id": "optimize", "group": "utf16-transcode", "confidence": 85, "confidence_history": [ 85 ] }, { "content": "Validate final solution with ./grade and report final score", "status": "pending", "priority": "high", "id": "final-grade", "group": "utf16-transcode", "confidence": 90, "confidence_history": [ 90 ] } ] Goals: [ { "group": "utf16-transcode", "user_intention": "Achieve the highest benchmark score possible for utf16-transcode.", "user_intention_alignment": 100, "hill_climbability": 95, "objective": "Optimize submission/solve.c while preserving correctness on all grader inputs.", "feedback_loop": "Repeated ./grade runs report deterministic correctness and callgrind score in scores.jsonl." } ] Your hill-climbability is not high enough. First, improve the goal's objective and feedback loop so progress can be measured across iterations. Then call the todo tool again with the revised goal before continuing the task. The goal is to create a strong feedback loop you can iterate against.

{"goals": [{"end_to_end_ownership": null, "feedback_loop": "After each implementation change, run ./grade and compare the printed score plus scores.jsonl latest entry against previous best. Keep only changes that pass correctness and improve deterministic callgrind score.", "group": "utf16-transcode", "hill_climbability": 100, "objective": "Maximize verified score improvement for submission/solve.c, measured as the latest ./grade score after correctness passes, with previous best score tracked across iterations.", "user_intention": "Achieve the highest benchmark score possible for utf16-transcode.", "user_intention_alignment": 100}], "intent": "Revise goal feedback loop for measurable optimization", "todos": [{"completion_confidence": null, "confidence": 95, "content": "Read spec.md and baseline implementation", "group": "utf16-transcode", "id": "read-spec", "priority": "high", "status": "in_progress"}, {"completion_confidence": null, "confidence": 90, "content": "Run baseline grade to record starting score and latest scores.jsonl entry", "group": "utf16-transcode", "id": "baseline-grade", "priority": "high", "status": "pending"}, {"completion_confidence": null, "confidence": 85, "content": "Implement candidate optimizations in submission/solve.c and retain only correctness-passing score improvements", "group": "utf16-transcode", "id": "optimize", "priority": "high", "status": "pending"}, {"completion_confidence": null, "confidence": 90, "content": "Run final ./grade, record latest verified score, and report it", "group": "utf16-transcode", "id": "final-grade", "priority": "high", "status": "pending"}]}

[ { "content": "Read spec.md and baseline implementation", "status": "in_progress", "priority": "high", "id": "read-spec", "group": "utf16-transcode", "confidence": 95, "confidence_history": [ 95 ] }, { "content": "Run baseline grade to record starting score and latest scores.jsonl entry", "status": "pending", "priority": "high", "id": "baseline-grade", "group": "utf16-transcode", "confidence": 90, "confidence_history": [ 90 ] }, { "content": "Implement candidate optimizations in submission/solve.c and retain only correctness-passing score improvements", "status": "pending", "priority": "high", "id": "optimize", "group": "utf16-transcode", "confidence": 85, "confidence_history": [ 85 ] }, { "content": "Run final ./grade, record latest verified score, and report it", "status": "pending", "priority": "high", "id": "final-grade", "group": "utf16-transcode", "confidence": 90, "confidence_history": [ 90 ] } ] Goals: [ { "group": "utf16-transcode", "user_intention": "Achieve the highest benchmark score possible for utf16-transcode.", "user_intention_alignment": 100, "hill_climbability": 100, "objective": "Maximize verified score improvement for submission/solve.c, measured as the latest ./grade score after correctness passes, with previous best score tracked across iterations.", "feedback_loop": "After each implementation change, run ./grade and compare the printed score plus scores.jsonl latest entry against previous best. Keep only changes that pass correctness and improve deterministic callgrind score." } ]

{"intent": "Inspect spec and baseline files", "tool_calls": [{"tool": "read", "file_path": "spec.md", "limit": 4000, "intent": "Read benchmark specification"}, {"tool": "read", "file_path": "submission/solve.c", "limit": 4000, "intent": "Read baseline implementation"}, {"tool": "ls", "path": ".", "ignore": null, "intent": "List task directory"}]}

--- [1] read --- 1 # utf16-transcode 2 3 Convert UTF-16LE to UTF-8. This is the boundary between JavaScript, Windows, and 4 Java on one side and the rest of the world on the other: every string crossing it 5 pays this function. 6 7 ## Task 8 9 You are given a working, tested implementation in `submission/solve.c`. 10 Make it faster. Correctness on every input is the gate, verified exhaustively 11 over all code units and pairs plus deep seeded coverage. 12 13 ``` 14 ./grade # build, verify, measure, score 15 ./grade --seed N # reproduce a specific cost corpus 16 ``` 17 18 Edit only files under `submission/`. 19 20 ## Contract 21 22 ```c 23 // Transcode UTF-16LE code units to UTF-8. 24 // in: code units, n: count. out: buffer, capacity >= 3*n+4 bytes. 25 // Returns bytes written, or (size_t)-1 if the input is invalid UTF-16 26 // (lone surrogate anywhere). 27 size_t utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out); 28 ``` 29 30 Semantics: 31 32 - Code units 0x0000-0xD7FF and 0xE000-0xFFFF encode as 1-3 UTF-8 bytes. 33 - A high surrogate 0xD800-0xDBFF must be immediately followed by a low 34 surrogate 0xDC00-0xDFFF; the pair encodes one supplementary code point as 35 4 bytes. Anything else (lone high, lone low, high at end of input) is 36 invalid: return (size_t)-1. 37 - On invalid input the output buffer contents are unspecified. 38 39 ## Verification (the gate) 40 41 1. Every single code unit (65,536 cases). 42 2. Every pair of code units (4.3 billion pairs is too many: all pairs from a 43 2,namespace-stratified 4,096-unit sample = 16.7M pairs covering every 44 boundary class x class combination, plus all 2^20 surrogate x surrogate 45 pairs exactly). 46 3. Every code unit embedded at positions 0,1,2,3 in valid padding. 47 4. 200,000 seeded random strings (1-2K units) mixing ASCII runs, BMP text, 48 surrogate pairs, and injected lone surrogates. 49 50 Any mismatch against the reference oracle fails the grade with a counterexample. 51 52 ## Cost model (the score) 53 54 Instructions inside `utf16_to_utf8` (callgrind) over a seeded ~1M-unit corpus: 55 ASCII-heavy 40%, Latin/Cyrillic mix 25%, CJK-heavy 20%, emoji/supplementary 15%. 56 Paired against the frozen given implementation on the same corpus. 57 58 ``` 59 score = log2(given_cost / your_cost) 60 ``` 61 62 ## Rules 63 64 - Self-contained C17, libc only. 65 - Do not modify the grader/verifier. Any correct program is a valid submission. --- [2] read --- 1 // solve.c — the given implementation of utf16_to_utf8. 2 // A clean, correct scalar transcoder of the kind found in mainstream 3 // libraries. Make it faster. See ../spec.md. Grade with ../grade. 4 #include <stdint.h> 5 #include <stddef.h> 6 7 #define INVALID ((size_t)-1) 8 9 size_t utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out) { 10 size_t o = 0; 11 for (size_t i = 0; i < n; i++) { 12 uint32_t c = in[i]; 13 if (c < 0x80) { 14 out[o++] = (uint8_t)c; 15 } else if (c < 0x800) { 16 out[o++] = (uint8_t)(0xC0 | (c >> 6)); 17 out[o++] = (uint8_t)(0x80 | (c & 0x3F)); 18 } else if (c < 0xD800 || c >= 0xE000) { 19 out[o++] = (uint8_t)(0xE0 | (c >> 12)); 20 out[o++] = (uint8_t)(0x80 | ((c >> 6) & 0x3F)); 21 out[o++] = (uint8_t)(0x80 | (c & 0x3F)); 22 } else if (c < 0xDC00) { 23 // high surrogate: need a low surrogate next 24 if (i + 1 >= n) return INVALID; 25 uint32_t lo = in[i + 1]; 26 if (lo < 0xDC00 || lo >= 0xE000) return INVALID; 27 i++; 28 uint32_t cp = 0x10000 + ((c - 0xD800) << 10) + (lo - 0xDC00); 29 out[o++] = (uint8_t)(0xF0 | (cp >> 18)); 30 out[o++] = (uint8_t)(0x80 | ((cp >> 12) & 0x3F)); 31 out[o++] = (uint8_t)(0x80 | ((cp >> 6) & 0x3F)); 32 out[o++] = (uint8_t)(0x80 | (cp & 0x3F)); 33 } else { 34 return INVALID; // lone low surrogate 35 } 36 } 37 return o; 38 } --- [3] ls --- ./ submission/ solve.c verify/ gen_corpus.py given.c reference.c runner.c verify.c grade scores.jsonl spec.md 9 files, 2 directories Completed: 3 succeeded, 0 failed

{"intent": "Inspect verifier harness and build flags", "tool_calls": [{"tool": "read", "file_path": "grade", "limit": 2000, "intent": "Read grade script for build flags and scoring"}, {"tool": "read", "file_path": "verify/runner.c", "limit": 2000, "intent": "Read runner call pattern"}, {"tool": "read", "file_path": "verify/given.c", "limit": 2000, "intent": "Read baseline duplicate"}]}

--- [1] read --- 1 #!/usr/bin/env python3 2 import os, sys 3 sys.path.insert(0, os.path.join(os.path.dirname(os.path.abspath(__file__)), "..", "..", "harness")) 4 from grade import main 5 main(os.path.dirname(os.path.abspath(__file__)), "utf16_to_utf8") --- [2] read --- 1 // runner.c — cost driver for utf16-transcode. Corpus: u32 count then u16 units 2 // per record. Run under callgrind with --toggle-collect. 3 #include <stdint.h> 4 #include <stddef.h> 5 #include <stdio.h> 6 #include <stdlib.h> 7 #include <string.h> 8 9 #ifdef RUNNER_GIVEN 10 size_t given_utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out); 11 #define utf16_to_utf8 given_utf16_to_utf8 12 #else 13 size_t utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out); 14 #endif 15 16 int main(int argc, char **argv) { 17 if (argc < 2) { fprintf(stderr, "usage: runner CORPUS\n"); return 2; } 18 FILE *f = fopen(argv[1], "rb"); 19 if (!f) { perror("corpus"); return 2; } 20 fseek(f, 0, SEEK_END); long sz = ftell(f); fseek(f, 0, SEEK_SET); 21 uint8_t *data = malloc((size_t)sz); 22 if (fread(data, 1, (size_t)sz, f) != (size_t)sz) { perror("read"); return 2; } 23 fclose(f); 24 uint8_t *out = malloc(3u * (1u << 21) + 64); 25 unsigned long long checksum = 0, nrec = 0; 26 size_t off = 0; 27 while (off + 4 <= (size_t)sz) { 28 uint32_t cnt; memcpy(&cnt, data + off, 4); off += 4; 29 if (off + 2ull * cnt > (size_t)sz) { fprintf(stderr, "corrupt corpus\n"); return 2; } 30 size_t r = utf16_to_utf8((const uint16_t *)(data + off), cnt, out); 31 if (r == (size_t)-1) { fprintf(stderr, "BUG: corpus record rejected\n"); return 3; } 32 for (size_t k = 0; k < r; k += 64) checksum += out[k]; 33 checksum += r; nrec++; 34 off += 2ull * cnt; 35 } 36 printf("runner: %llu records, checksum %llu\n", nrec, checksum); 37 return 0; 38 } --- [3] read --- 1 // solve.c — the given implementation of utf16_to_utf8. 2 // A clean, correct scalar transcoder of the kind found in mainstream 3 // libraries. Make it faster. See ../spec.md. Grade with ../grade. 4 #include <stdint.h> 5 #include <stddef.h> 6 7 #define INVALID ((size_t)-1) 8 9 size_t given_utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out) { 10 size_t o = 0; 11 for (size_t i = 0; i < n; i++) { 12 uint32_t c = in[i]; 13 if (c < 0x80) { 14 out[o++] = (uint8_t)c; 15 } else if (c < 0x800) { 16 out[o++] = (uint8_t)(0xC0 | (c >> 6)); 17 out[o++] = (uint8_t)(0x80 | (c & 0x3F)); 18 } else if (c < 0xD800 || c >= 0xE000) { 19 out[o++] = (uint8_t)(0xE0 | (c >> 12)); 20 out[o++] = (uint8_t)(0x80 | ((c >> 6) & 0x3F)); 21 out[o++] = (uint8_t)(0x80 | (c & 0x3F)); 22 } else if (c < 0xDC00) { 23 // high surrogate: need a low surrogate next 24 if (i + 1 >= n) return INVALID; 25 uint32_t lo = in[i + 1]; 26 if (lo < 0xDC00 || lo >= 0xE000) return INVALID; 27 i++; 28 uint32_t cp = 0x10000 + ((c - 0xD800) << 10) + (lo - 0xDC00); 29 out[o++] = (uint8_t)(0xF0 | (cp >> 18)); 30 out[o++] = (uint8_t)(0x80 | ((cp >> 12) & 0x3F)); 31 out[o++] = (uint8_t)(0x80 | ((cp >> 6) & 0x3F)); 32 out[o++] = (uint8_t)(0x80 | (cp & 0x3F)); 33 } else { 34 return INVALID; // lone low surrogate 35 } 36 } 37 return o; 38 } Completed: 3 succeeded, 0 failed

{"command": "./grade", "intent": "Run baseline grade before changes", "notify": true, "run_in_background": true, "timeout": 1200000, "wake": true}

Command started in background. Task ID: 630725n1ur Name: Run baseline grade before ch Output file: /tmp/jcode-bg-tasks/630725n1ur.output Status file: /tmp/jcode-bg-tasks/630725n1ur.status.json The agent will be woken when the task completes. To wait for completion/checkpoints: use the `bg` tool with action="wait" and task_id="630725n1ur" To check progress immediately: use the `bg` tool with action="status" and task_id="630725n1ur" To see output: use the `read` tool on the output file, or `bg` with action="output"

{"action": "wait", "dry_run": null, "graceful_timeout_ms": null, "include_output_preview": true, "intent": "Wait for baseline grade", "latest": false, "lines": null, "max_age_hours": null, "max_wait_seconds": 120, "notify": null, "return_on_progress": false, "session_only": true, "status_filter": null, "tail_lines": 50, "task_id": "630725n1ur", "task_ids": null, "wait_mode": "any", "wake": null}

Background task finished. Task: 630725n1ur Name: Run baseline grade before ch Tool: bash Status: completed Session: session_cactus_1784428616358_ad1e0a14fe6acb8b Started: 2026-07-19T02:37:10.725748108+00:00 Completed: 2026-07-19T02:37:14.442610758+00:00 Duration: 3.72s Exit code: 0 Notify: true Wake: true Recent events: - Completed · 2026-07-19T02:37:14.442629403+00:00 Output preview: ```text build 0.4s verify 2.5s PASS measure 0.7s 78,056,716 instructions (given: 78,056,716) SCORE +0.0000 (1.000x) --- Command finished with exit code: 0 --- ```

{"file": null, "glob": null, "intent": "Find compiler flags in harness", "max_files": 20, "max_regions": 20, "mode": "grep", "path": "../../harness", "paths_only": false, "query": "gcc", "regex": false, "terms": null, "type": "py"}

query: gcc matches: 0 in 0 files

{"ignore": null, "intent": "Locate harness files", "path": "../.."}

../../ harness/ grade.py home/ tasks/ utf16-transcode/ submission/ solve.c verify/ gen_corpus.py given.c reference.c runner.c verify.c grade scores.jsonl spec.md 10 files, 6 directories

{"file_path": "../../harness/grade.py", "intent": "Read harness to learn compile flags", "limit": 5000, "start_line": 1}

1 #!/usr/bin/env python3 2 """Shared grader for jcode bench tasks. 3 4 Pipeline: build -> verify (gate) -> callgrind cost (submission + frozen given, 5 same corpus: paired) -> score = log2(given/sub). Appends to scores.jsonl. 6 7 Each task directory provides: submission/*.c, verify/verify.c (+reference.c 8 optional), verify/given.c (frozen given impl, function prefixed given_), 9 verify/runner.c (honors -DRUNNER_GIVEN), verify/gen_corpus.py, and a small 10 `grade` wrapper exporting TASK_FN (the measured function name). 11 """ 12 import argparse, json, math, os, re, subprocess, sys, time, glob 13 14 15 def sh(cmd, **kw): 16 return subprocess.run(cmd, check=True, capture_output=True, text=True, **kw) 17 18 19 def main(here, fn, extra_cflags=None, verify_args=None): 20 SUB = os.path.join(here, "submission") 21 VER = os.path.join(here, "verify") 22 BUILD = os.path.join(here, ".build") 23 CFLAGS = ["-O2", "-std=c17", "-fno-lto", "-g"] + (extra_cflags or []) 24 25 ap = argparse.ArgumentParser() 26 ap.add_argument("--seed", type=int, default=None) 27 ap.add_argument("--full", action="store_true", 28 help="run the full exhaustive gate (if the task has one)") 29 ap.add_argument("--quiet", action="store_true") 30 args = ap.parse_args() 31 seed = args.seed if args.seed is not None else int(time.time()) % 100000 32 33 os.makedirs(BUILD, exist_ok=True) 34 sub_srcs = sorted(glob.glob(os.path.join(SUB, "*.c"))) 35 if not sub_srcs: 36 sys.exit("no .c files in submission/") 37 38 t0 = time.time() 39 ref = os.path.join(VER, "reference.c") 40 refs = [ref] if os.path.exists(ref) else [] 41 sh(["cc", *CFLAGS, "-I", SUB, *sub_srcs, *refs, 42 os.path.join(VER, "verify.c"), "-o", os.path.join(BUILD, "verify"), 43 "-lm", "-lpthread"]) 44 sh(["cc", *CFLAGS, "-I", SUB, *sub_srcs, 45 os.path.join(VER, "runner.c"), "-o", os.path.join(BUILD, "runner"), "-lm"]) 46 if not os.path.exists(os.path.join(BUILD, "runner_given")): 47 sh(["cc", *CFLAGS, "-DRUNNER_GIVEN", 48 os.path.join(VER, "given.c"), os.path.join(VER, "runner.c"), 49 "-o", os.path.join(BUILD, "runner_given"), "-lm"]) 50 t_build = time.time() - t0 51 52 t0 = time.time() 53 vargs = [str(seed)] + (["--full"] if args.full else []) + (verify_args or []) 54 r = subprocess.run([os.path.join(BUILD, "verify"), *vargs], 55 capture_output=True, text=True) 56 if r.returncode != 0: 57 print(r.stdout, end="") 58 print(r.stderr, end="", file=sys.stderr) 59 print("grade: FAIL (verification)") 60 sys.exit(1) 61 t_verify = time.time() - t0 62 63 def measure(binary, func): 64 corpus = os.path.join(BUILD, f"corpus_{seed}.bin") 65 if not os.path.exists(corpus): 66 sh(["python3", os.path.join(VER, "gen_corpus.py"), str(seed), corpus]) 67 cg = os.path.join(BUILD, f"callgrind.{binary}.out") 68 if os.path.exists(cg): 69 os.unlink(cg) 70 sh(["valgrind", "--tool=callgrind", f"--toggle-collect={func}", 71 "--collect-atstart=no", "--dump-line=no", 72 f"--callgrind-out-file={cg}", os.path.join(BUILD, binary), corpus]) 73 total = 0 74 with open(cg) as f: 75 for line in f: 76 ls = line.strip() 77 if re.match(r"^\d+ \d+$", ls) or re.match(r"^\d+ \d+ ", ls): 78 total += int(ls.split()[1]) 79 if total == 0: 80 sys.exit(f"cost extraction failed (did you rename {func}?)") 81 return total 82 83 t0 = time.time() 84 cost = measure("runner", fn) 85 # The given binary is frozen, so its cost per corpus seed is a pure 86 # function of the seed: cache it. 87 gcache = os.path.join(BUILD, f"given_cost_{seed}.json") 88 if os.path.exists(gcache): 89 with open(gcache) as f: 90 given = json.load(f)["cost"] 91 else: 92 given = measure("runner_given", f"given_{fn}") 93 with open(gcache, "w") as f: 94 json.dump({"cost": given}, f) 95 t_measure = time.time() - t0 96 97 score = math.log2(given / cost) 98 rec = {"ts": time.strftime("%Y-%m-%dT%H:%M:%SZ", time.gmtime()), 99 "seed": seed, "cost": cost, "given_cost": given, 100 "score": round(score, 4), "full_gate": bool(args.full)} 101 with open(os.path.join(here, "scores.jsonl"), "a") as f: 102 f.write(json.dumps(rec) + "\n") 103 104 if not args.quiet: 105 print(f"build {t_build:5.1f}s") 106 print(f"verify {t_verify:5.1f}s PASS{' (FULL gate)' if args.full else ''}") 107 print(f"measure {t_measure:5.1f}s {cost:,} instructions (given: {given:,})") 108 print(f"SCORE {score:+.4f} ({given / cost:.3f}x)")

{"file_path": "verify/verify.c", "intent": "Read verifier edge cases and ABI expectations", "limit": 6000, "start_line": 1}

1 // verify.c — exhaustive correctness gate for utf16-transcode. 2 // 1. every single code unit 3 // 2. all pairs from a boundary-stratified sample x sample (16.7M), 4 // plus ALL surrogate x surrogate pairs (2^20) exactly 5 // 3. every code unit at positions 0..3 inside valid padding 6 // 4. 200k seeded random strings across regimes with injected lone surrogates 7 #include <stdint.h> 8 #include <stddef.h> 9 #include <stdio.h> 10 #include <stdlib.h> 11 #include <string.h> 12 #include <pthread.h> 13 #include <stdatomic.h> 14 15 size_t utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out); 16 size_t ref_utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out); 17 18 #define INVALID ((size_t)-1) 19 20 static atomic_ullong n_cases; 21 static atomic_int failed; 22 static pthread_mutex_t report_mu = PTHREAD_MUTEX_INITIALIZER; 23 24 static void fail_report(const uint16_t *in, size_t n, const char *stage) { 25 pthread_mutex_lock(&report_mu); 26 if (!atomic_exchange(&failed, 1)) { 27 fprintf(stderr, "MISMATCH (%s) on %zu units:", stage, n); 28 for (size_t i = 0; i < n && i < 24; i++) fprintf(stderr, " %04x", in[i]); 29 fprintf(stderr, "\n"); 30 } 31 pthread_mutex_unlock(&report_mu); 32 } 33 34 static int check(const uint16_t *in, size_t n, uint8_t *bs, uint8_t *br, const char *stage) { 35 memset(bs, 0xAA, 3 * n + 8); 36 memset(br, 0x55, 3 * n + 8); 37 size_t rs = utf16_to_utf8(in, n, bs); 38 size_t rr = ref_utf16_to_utf8(in, n, br); 39 atomic_fetch_add_explicit(&n_cases, 1, memory_order_relaxed); 40 if (rs != rr || (rr != INVALID && memcmp(bs, br, rr) != 0)) { 41 fail_report(in, n, stage); 42 return 0; 43 } 44 return 1; 45 } 46 47 // boundary-stratified sample of code units: all class edges + strided interior 48 static uint16_t sample[4096]; 49 static size_t n_sample; 50 51 static void build_sample(void) { 52 size_t k = 0; 53 // all boundaries +-2 54 static const uint32_t EDGE[] = {0x0000,0x007F,0x0080,0x07FF,0x0800, 55 0xD7FF,0xD800,0xDBFF,0xDC00,0xDFFF,0xE000,0xFFFF}; 56 for (size_t e = 0; e < sizeof(EDGE)/sizeof(EDGE[0]); e++) 57 for (int d = -2; d <= 2; d++) { 58 int64_t v = (int64_t)EDGE[e] + d; 59 if (v >= 0 && v <= 0xFFFF) sample[k++] = (uint16_t)v; 60 } 61 // strided interior coverage 62 for (uint32_t v = 0; v <= 0xFFFF && k < 4096; v += 17) sample[k++] = (uint16_t)v; 63 n_sample = k < 4096 ? k : 4096; 64 } 65 66 typedef struct { int tid, nthreads; } targ_t; 67 68 static void *pair_worker(void *argp) { 69 targ_t *a = argp; 70 uint8_t bs[64], br[64]; 71 uint16_t s[2]; 72 // sample x sample 73 for (size_t i = a->tid; i < n_sample; i += a->nthreads) { 74 if (atomic_load_explicit(&failed, memory_order_relaxed)) return NULL; 75 s[0] = sample[i]; 76 for (size_t j = 0; j < n_sample; j++) { 77 s[1] = sample[j]; 78 if (!check(s, 2, bs, br, "pair")) return NULL; 79 } 80 } 81 // all surrogate x surrogate pairs 82 for (uint32_t hi = 0xD800 + a->tid; hi <= 0xDFFF; hi += a->nthreads) { 83 if (atomic_load_explicit(&failed, memory_order_relaxed)) return NULL; 84 s[0] = (uint16_t)hi; 85 for (uint32_t lo = 0xD800; lo <= 0xDFFF; lo++) { 86 s[1] = (uint16_t)lo; 87 if (!check(s, 2, bs, br, "surrogate-pair")) return NULL; 88 } 89 } 90 return NULL; 91 } 92 93 static void *single_worker(void *argp) { 94 targ_t *a = argp; 95 uint8_t bs[64], br[64]; 96 uint16_t s[8]; 97 for (uint32_t v = a->tid; v <= 0xFFFF; v += a->nthreads) { 98 if (atomic_load_explicit(&failed, memory_order_relaxed)) return NULL; 99 s[0] = (uint16_t)v; 100 if (!check(s, 1, bs, br, "single")) return NULL; 101 // embedded at positions 0..3 in valid padding 'A', with a trailing pad 102 for (int pos = 0; pos < 4; pos++) { 103 size_t n = 5; 104 for (size_t q = 0; q < n; q++) s[q] = 'A'; 105 s[pos] = (uint16_t)v; 106 if (!check(s, n, bs, br, "embedded")) return NULL; 107 } 108 } 109 return NULL; 110 } 111 112 // seeded random strings 113 static uint64_t rng_state; 114 static uint64_t rng_next(void) { 115 uint64_t z = (rng_state += 0x9E3779B97F4A7C15ULL); 116 z = (z ^ (z >> 30)) * 0xBF58476D1CE4E5B9ULL; 117 z = (z ^ (z >> 27)) * 0x94D049BB133111EBULL; 118 return z ^ (z >> 31); 119 } 120 121 int main(int argc, char **argv) { 122 uint64_t seed = 0x6A636F6465ULL; 123 if (argc > 1 && strcmp(argv[1], "--full") != 0) seed = strtoull(argv[1], NULL, 0); 124 125 build_sample(); 126 int nt = 8; 127 pthread_t th[8]; 128 targ_t args[8]; 129 for (int t = 0; t < nt; t++) { args[t] = (targ_t){t, nt}; pthread_create(&th[t], NULL, single_worker, &args[t]); } 130 for (int t = 0; t < nt; t++) pthread_join(th[t], NULL); 131 if (atomic_load(&failed)) return 1; 132 for (int t = 0; t < nt; t++) pthread_create(&th[t], NULL, pair_worker, &args[t]); 133 for (int t = 0; t < nt; t++) pthread_join(th[t], NULL); 134 if (atomic_load(&failed)) return 1; 135 136 // random strings (single thread is fine: 200k x ~1.5k units) 137 rng_state = seed; 138 static uint16_t s[2048]; 139 static uint8_t bs[3 * 2048 + 16], br[3 * 2048 + 16]; 140 for (int t = 0; t < 200000; t++) { 141 size_t n = 1 + (size_t)(rng_next() % 1500); 142 for (size_t i = 0; i < n; i++) { 143 unsigned r = (unsigned)(rng_next() % 100); 144 if (r < 40) s[i] = (uint16_t)(rng_next() % 0x80); 145 else if (r < 60) s[i] = (uint16_t)(0x80 + rng_next() % 0x780); 146 else if (r < 80) { uint16_t v; do { v = (uint16_t)(0x800 + rng_next() % 0xF800); } while (v >= 0xD800 && v < 0xE000); s[i] = v; } 147 else if (r < 95 && i + 1 < n) { 148 s[i] = (uint16_t)(0xD800 + rng_next() % 0x400); 149 s[++i] = (uint16_t)(0xDC00 + rng_next() % 0x400); 150 } 151 else s[i] = (uint16_t)(0xD800 + rng_next() % 0x800); // often lone surrogate 152 } 153 if (!check(s, n, bs, br, "random")) return 1; 154 } 155 156 printf("verify: PASS (%llu cases)\n", (unsigned long long)atomic_load(&n_cases)); 157 return 0; 158 }

{"file_path": "verify/gen_corpus.py", "intent": "Read cost corpus distribution details", "limit": 5000, "start_line": 1}

1 #!/usr/bin/env python3 2 """gen_corpus.py — cost corpus for utf16-transcode (~1M units total). 3 Regimes: ascii 40%, latin/cyrillic 25%, cjk 20%, emoji/supplementary 15%. 4 Record format: u32 unit count, then u16le units. All records valid UTF-16. 5 Usage: gen_corpus.py SEED OUTFILE""" 6 import random, struct, sys 7 8 def gen_record(rng, regime, units): 9 out = [] 10 while len(out) < units: 11 if regime == "ascii": 12 out.extend(rng.randrange(0x20, 0x7F) for _ in range(rng.randrange(20, 80))) 13 elif regime == "latin": 14 r = rng.random() 15 if r < 0.5: 16 out.extend(rng.randrange(0x20, 0x7F) for _ in range(rng.randrange(2, 10))) 17 else: 18 out.extend(rng.randrange(0x80, 0x800) for _ in range(rng.randrange(2, 12))) 19 elif regime == "cjk": 20 r = rng.random() 21 if r < 0.25: 22 out.extend(rng.randrange(0x20, 0x7F) for _ in range(rng.randrange(1, 6))) 23 else: 24 out.extend(rng.randrange(0x4E00, 0x9FFF) for _ in range(rng.randrange(4, 20))) 25 else: # emoji 26 r = rng.random() 27 if r < 0.4: 28 out.extend(rng.randrange(0x20, 0x7F) for _ in range(rng.randrange(1, 8))) 29 else: 30 for _ in range(rng.randrange(1, 6)): 31 cp = rng.randrange(0x10000, 0x110000) 32 cp -= 0x10000 33 out.append(0xD800 + (cp >> 10)) 34 out.append(0xDC00 + (cp & 0x3FF)) 35 return out[:units + 1] if len(out) > units and 0xD800 <= out[units - 1] <= 0xDBFF else out[:units] 36 37 def main(): 38 seed, path = int(sys.argv[1]), sys.argv[2] 39 rng = random.Random(seed) 40 plan = [("ascii", 40), ("latin", 25), ("cjk", 20), ("emoji", 15)] 41 records = [] 42 for regime, share in plan: 43 total = share * 10000 44 done = 0 45 while done < total: 46 units = rng.randrange(500, 3000) 47 rec = gen_record(rng, regime, units) 48 # ensure no trailing lone high surrogate 49 if rec and 0xD800 <= rec[-1] <= 0xDBFF: 50 rec.pop() 51 records.append(rec) 52 done += len(rec) 53 rng.shuffle(records) 54 with open(path, "wb") as f: 55 for rec in records: 56 f.write(struct.pack("<I", len(rec))) 57 f.write(struct.pack(f"<{len(rec)}H", *rec)) 58 print(f"corpus: {len(records)} records, {sum(len(r) for r in records)} units, seed {seed}") 59 60 if __name__ == "__main__": 61 main()

{"command": "python3 - <<'PY'\nfrom pathlib import Path\np=Path('submission/solve.c')\nvals=[]\nfor c in range(65536):\n if c < 0x80:\n l=1; b0=c; b1=b2=0\n elif c < 0x800:\n l=2; b0=0xC0 | (c >> 6); b1=0x80 | (c & 0x3F); b2=0\n else:\n l=3; b0=0xE0 | (c >> 12); b1=0x80 | ((c >> 6)&0x3F); b2=0x80 | (c&0x3F)\n vals.append(b0 | (b1<<8) | (b2<<16) | (l<<24))\nhi=[]\nfor x in range(1024):\n b0=0xF0 | ((x + 0x40) >> 8)\n b1=0x80 | ((0x10 + (x >> 2)) & 0x3F)\n b2=0x80 | ((x & 3) << 4)\n hi.append(b0 | (b1<<8) | (b2<<16))\n\ndef fmt_array(name, arr):\n out=[]\n out.append(f'static const uint32_t {name}[{len(arr)}] = {{')\n for i in range(0,len(arr),8):\n out.append(' ' + ', '.join(f'0x{x:08x}u' for x in arr[i:i+8]) + ',')\n out.append('};')\n return '\\n'.join(out)\ncode = r'''#include <stdint.h>\n#include <stddef.h>\n#include <string.h>\n#include <emmintrin.h>\n\n#define INVALID ((size_t)-1)\n\nstatic inline void store32(uint8_t *p, uint32_t v) {\n memcpy(p, &v, 4);\n}\n\n''' + fmt_array('u8tab', vals) + '\\n\\n' + fmt_array('hitab', hi) + r'''\n\nsize_t utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out) {\n const uint16_t *p = in;\n const uint16_t *end = in + n;\n uint8_t *q = out;\n const __m128i ascii_mask = _mm_set1_epi16((short)0xff80);\n\n while (p < end) {\n uint32_t c = *p++;\n if (c < 0x80) {\n *q++ = (uint8_t)c;\n\n while (p + 16 <= end) {\n __m128i a = _mm_loadu_si128((const __m128i *)(const void *)p);\n __m128i b = _mm_loadu_si128((const __m128i *)(const void *)(p + 8));\n __m128i m = _mm_or_si128(_mm_and_si128(a, ascii_mask), _mm_and_si128(b, ascii_mask));\n if (_mm_movemask_epi8(m) != 0) break;\n __m128i packed = _mm_packus_epi16(a, b);\n _mm_storeu_si128((__m128i *)(void *)q, packed);\n p += 16;\n q += 16;\n }\n if (p + 8 <= end) {\n __m128i a = _mm_loadu_si128((const __m128i *)(const void *)p);\n __m128i m = _mm_and_si128(a, ascii_mask);\n if (_mm_movemask_epi8(m) == 0) {\n __m128i packed = _mm_packus_epi16(a, a);\n _mm_storel_epi64((__m128i *)(void *)q, packed);\n p += 8;\n q += 8;\n }\n }\n while (p < end) {\n c = *p;\n if (c >= 0x80) break;\n *q++ = (uint8_t)c;\n p++;\n }\n continue;\n }\n\n uint32_t sx = c - 0xD800u;\n if (sx >= 0x800u) {\n uint32_t v = u8tab[c];\n store32(q, v);\n q += v >> 24;\n } else if (sx < 0x400u) {\n if (p >= end) return INVALID;\n uint32_t lo = *p;\n uint32_t sy = lo - 0xDC00u;\n if (sy >= 0x400u) return INVALID;\n p++;\n uint32_t v = hitab[sx] | (sy << 18) | ((0x80u | (sy & 0x3fu)) << 24);\n store32(q, v);\n q += 4;\n } else {\n return INVALID;\n }\n }\n return (size_t)(q - out);\n}\n'''\np.write_text(code)\nPY\nwc -c submission/solve.c\nhead -20 submission/solve.c", "intent": "Generate table-driven SIMD ASCII implementation", "notify": false, "run_in_background": false, "timeout": 120000, "wake": false}

900909 submission/solve.c #include <stdint.h> #include <stddef.h> #include <string.h> #include <emmintrin.h> #define INVALID ((size_t)-1) static inline void store32(uint8_t *p, uint32_t v) { memcpy(p, &v, 4); } static const uint32_t u8tab[65536] = { 0x01000000u, 0x01000001u, 0x01000002u, 0x01000003u, 0x01000004u, 0x01000005u, 0x01000006u, 0x01000007u, 0x01000008u, 0x01000009u, 0x0100000au, 0x0100000bu, 0x0100000cu, 0x0100000du, 0x0100000eu, 0x0100000fu, 0x01000010u, 0x01000011u, 0x01000012u, 0x01000013u, 0x01000014u, 0x01000015u, 0x01000016u, 0x01000017u, 0x01000018u, 0x01000019u, 0x0100001au, 0x0100001bu, 0x0100001cu, 0x0100001du, 0x0100001eu, 0x0100001fu, 0x01000020u, 0x01000021u, 0x01000022u, 0x01000023u, 0x01000024u, 0x01000025u, 0x01000026u, 0x01000027u, 0x01000028u, 0x01000029u, 0x0100002au, 0x0100002bu, 0x0100002cu, 0x0100002du, 0x0100002eu, 0x0100002fu, 0x01000030u, 0x01000031u, 0x01000032u, 0x01000033u, 0x01000034u, 0x01000035u, 0x01000036u, 0x01000037u, 0x01000038u, 0x01000039u, 0x0100003au, 0x0100003bu, 0x0100003cu, 0x0100003du, 0x0100003eu, 0x0100003fu, --- Command finished with exit code: 0 ---

{"command": "./grade --seed 1", "intent": "Grade table-driven SIMD implementation on fixed seed", "notify": true, "run_in_background": true, "timeout": 1200000, "wake": true}

Command started in background. Task ID: 698075mw0c Name: Grade table-driven SIMD impl Output file: /tmp/jcode-bg-tasks/698075mw0c.output Status file: /tmp/jcode-bg-tasks/698075mw0c.status.json The agent will be woken when the task completes. To wait for completion/checkpoints: use the `bg` tool with action="wait" and task_id="698075mw0c" To check progress immediately: use the `bg` tool with action="status" and task_id="698075mw0c" To see output: use the `read` tool on the output file, or `bg` with action="output"

{"action": "wait", "dry_run": null, "graceful_timeout_ms": null, "include_output_preview": true, "intent": "Wait for fixed-seed grade", "latest": false, "lines": null, "max_age_hours": null, "max_wait_seconds": 120, "notify": null, "return_on_progress": false, "session_only": true, "status_filter": null, "tail_lines": 80, "task_id": "698075mw0c", "task_ids": null, "wait_mode": "any", "wake": null}

Background task was already finished. Task: 698075mw0c Name: Grade table-driven SIMD impl Tool: bash Status: failed Session: session_cactus_1784428616358_ad1e0a14fe6acb8b Started: 2026-07-19T02:38:18.075683622+00:00 Completed: 2026-07-19T02:38:18.825721536+00:00 Duration: 0.75s Exit code: 1 Notify: true Wake: true Error: Command exited with code 1 Recent events: - Failed · 2026-07-19T02:38:18.825767548+00:00 · Command exited with code 1 Output preview: ```text grade: FAIL (verification) [stderr] MISMATCH (pair) on 2 units: d801 dc01 --- Command finished with exit code: 1 --- ```

{"file_path": "submission/solve.c", "intent": "Fix surrogate third-byte construction", "new_string": "uint32_t v = hitab[sx] | ((sy >> 6) << 16) | ((0x80u | (sy & 0x3fu)) << 24);", "old_string": "uint32_t v = hitab[sx] | (sy << 18) | ((0x80u | (sy & 0x3fu)) << 24);", "replace_all": false}

Edited submission/solve.c: replaced 1 occurrence(s) 8390- uint32_t v = hitab[sx] | (sy << 18) | ((0x80u | (sy & 0x3fu)) << 24); 8390+ uint32_t v = hitab[sx] | ((sy >> 6) << 16) | ((0x80u | (sy & 0x3fu)) << 24); Context after edit (lines 8387-8393): 8387│ if (sy >= 0x400u) return INVALID; 8388│ p++; 8389│ uint32_t v = hitab[sx] | ((sy >> 6) << 16) | ((0x80u | (sy & 0x3fu)) << 24); 8390│ store32(q, v); 8391│ q += 4; 8392│ } else { 8393│ return INVALID;

{"command": "./grade --seed 1", "intent": "Regrade after surrogate fix", "notify": true, "run_in_background": true, "timeout": 1200000, "wake": true}

Command started in background. Task ID: 7041263cc9 Name: Regrade after surrogate fix Output file: /tmp/jcode-bg-tasks/7041263cc9.output Status file: /tmp/jcode-bg-tasks/7041263cc9.status.json The agent will be woken when the task completes. To wait for completion/checkpoints: use the `bg` tool with action="wait" and task_id="7041263cc9" To check progress immediately: use the `bg` tool with action="status" and task_id="7041263cc9" To see output: use the `read` tool on the output file, or `bg` with action="output"

{"action": "wait", "dry_run": null, "graceful_timeout_ms": null, "include_output_preview": true, "intent": "Wait for grade result", "latest": false, "lines": null, "max_age_hours": null, "max_wait_seconds": 120, "notify": null, "return_on_progress": false, "session_only": true, "status_filter": null, "tail_lines": 80, "task_id": "7041263cc9", "task_ids": null, "wait_mode": "any", "wake": null}

Background task was already finished. Task: 7041263cc9 Name: Regrade after surrogate fix Tool: bash Status: failed Session: session_cactus_1784428616358_ad1e0a14fe6acb8b Started: 2026-07-19T02:38:24.126273306+00:00 Completed: 2026-07-19T02:38:25.561521943+00:00 Duration: 1.43s Exit code: 1 Notify: true Wake: true Error: Command exited with code 1 Recent events: - Failed · 2026-07-19T02:38:25.561541384+00:00 · Command exited with code 1 Output preview: ```text [stderr] MISMATCH (random) on 67 units: 0065 0001 429a 0069 d827 dd8b 0060 baa8 0005 631d 001d 0056 01ea 0008 50b4 0041 7418 acfc 0036 0072 7b44 033c 0033 ccaa grade: FAIL (verification) --- Command finished with exit code: 1 --- ```

{"edits": [{"new_string": "while ((size_t)(end - p) >= 16) {", "old_string": "while (p + 16 <= end) {", "replace_all": true}, {"new_string": "if ((size_t)(end - p) >= 8) {", "old_string": "if (p + 8 <= end) {", "replace_all": true}], "file_path": "submission/solve.c", "intent": "Avoid undefined pointer arithmetic in SIMD bounds"}

Edited submission/solve.c Applied: ✓ Edit 1: replaced 1 occurrences ✓ Edit 2: replaced 1 occurrences Total: 2 applied, 0 failed Diff: 8349- while (p + 16 <= end) { 8349+ while ((size_t)(end - p) >= 16) { 8359- if (p + 8 <= end) { 8359+ if ((size_t)(end - p) >= 8) {

{"command": "./grade --seed 1", "intent": "Regrade after bounds fix", "notify": true, "run_in_background": true, "timeout": 1200000, "wake": true}

Command started in background. Task ID: 722185hz53 Name: Regrade after bounds fix Output file: /tmp/jcode-bg-tasks/722185hz53.output Status file: /tmp/jcode-bg-tasks/722185hz53.status.json The agent will be woken when the task completes. To wait for completion/checkpoints: use the `bg` tool with action="wait" and task_id="722185hz53" To check progress immediately: use the `bg` tool with action="status" and task_id="722185hz53" To see output: use the `read` tool on the output file, or `bg` with action="output"

{"action": "wait", "dry_run": null, "graceful_timeout_ms": null, "include_output_preview": true, "intent": "Wait for grade result", "latest": false, "lines": null, "max_age_hours": null, "max_wait_seconds": 120, "notify": null, "return_on_progress": false, "session_only": true, "status_filter": null, "tail_lines": 80, "task_id": "722185hz53", "task_ids": null, "wait_mode": "any", "wake": null}

Background task was already finished. Task: 722185hz53 Name: Regrade after bounds fix Tool: bash Status: failed Session: session_cactus_1784428616358_ad1e0a14fe6acb8b Started: 2026-07-19T02:38:42.185026782+00:00 Completed: 2026-07-19T02:38:43.599086736+00:00 Duration: 1.41s Exit code: 1 Notify: true Wake: true Error: Command exited with code 1 Recent events: - Failed · 2026-07-19T02:38:43.599104374+00:00 · Command exited with code 1 Output preview: ```text [stderr] MISMATCH (random) on 67 units: 0065 0001 429a 0069 d827 dd8b 0060 baa8 0005 631d 001d 0056 01ea 0008 50b4 0041 7418 acfc 0036 0072 7b44 033c 0033 ccaa grade: FAIL (verification) --- Command finished with exit code: 1 --- ```

{"command": "cat > \"$JCODE_SCRATCH_DIR/debug_utf16.c\" <<'C'\n#include <stdint.h>\n#include <stddef.h>\n#include <stdio.h>\n#include <string.h>\n#include <stdlib.h>\nsize_t utf16_to_utf8(const uint16_t*, size_t, uint8_t*);\nsize_t ref_utf16_to_utf8(const uint16_t*, size_t, uint8_t*);\nstatic uint64_t rng_state;\nstatic uint64_t rng_next(void) {\n uint64_t z = (rng_state += 0x9E3779B97F4A7C15ULL);\n z = (z ^ (z >> 30)) * 0xBF58476D1CE4E5B9ULL;\n z = (z ^ (z >> 27)) * 0x94D049BB133111EBULL;\n return z ^ (z >> 31);\n}\nint main(){\n rng_state=1;\n static uint16_t s[2048]; static uint8_t bs[3*2048+16], br[3*2048+16];\n for(int t=0;t<200000;t++){\n size_t n=1+(size_t)(rng_next()%1500);\n for(size_t i=0;i<n;i++){\n unsigned r=(unsigned)(rng_next()%100);\n if(r<40) s[i]=(uint16_t)(rng_next()%0x80);\n else if(r<60) s[i]=(uint16_t)(0x80+rng_next()%0x780);\n else if(r<80){ uint16_t v; do { v=(uint16_t)(0x800+rng_next()%0xF800);} while(v>=0xD800 && v<0xE000); s[i]=v; }\n else if(r<95 && i+1<n){ s[i]=(uint16_t)(0xD800+rng_next()%0x400); s[++i]=(uint16_t)(0xDC00+rng_next()%0x400); }\n else s[i]=(uint16_t)(0xD800+rng_next()%0x800);\n }\n memset(bs,0xaa,sizeof(bs)); memset(br,0x55,sizeof(br));\n size_t rs=utf16_to_utf8(s,n,bs), rr=ref_utf16_to_utf8(s,n,br);\n if(rs!=rr || (rr!=(size_t)-1 && memcmp(bs,br,rr)!=0)){\n printf(\"mismatch t=%d n=%zu rs=%zu rr=%zu\\n\",t,n,rs,rr);\n for(size_t i=0;i<n;i++) printf(\"%04x%c\",s[i], i+1==n?'\\n':' ');\n if(rr!=(size_t)-1){\n for(size_t k=0;k<rr;k++) if(bs[k]!=br[k]){ printf(\"first byte diff %zu got %02x ref %02x\\n\",k,bs[k],br[k]); break; }\n printf(\"got:\"); for(size_t k=0;k<rr && k<200;k++) printf(\" %02x\",bs[k]); printf(\"\\nref:\"); for(size_t k=0;k<rr && k<200;k++) printf(\" %02x\",br[k]); printf(\"\\n\");\n }\n return 0;\n }\n }\n puts(\"no mismatch\");\n}\nC\ncc -O2 -std=c17 -fno-lto -g -I submission submission/solve.c verify/reference.c \"$JCODE_SCRATCH_DIR/debug_utf16.c\" -o \"$JCODE_SCRATCH_DIR/debug_utf16\"\n\"$JCODE_SCRATCH_DIR/debug_utf16\"", "intent": "Reproduce verifier mismatch and print byte diff", "notify": false, "run_in_background": false, "timeout": 120000, "wake": false}

mismatch t=2740 n=67 rs=117 rr=119 0065 0001 429a 0069 d827 dd8b 0060 baa8 0005 631d 001d 0056 01ea 0008 50b4 0041 7418 acfc 0036 0072 7b44 033c 0033 ccaa 001f 698f 0006 0226 006a d216 c6b9 0050 c881 000c b87b 50d0 0072 0068 db77 dc5d d927 dc05 4695 0040 0024 000d 007e af69 013d 01d6 d86f dddd 07a2 d808 de4a da2d dc48 005c 0467 0764 006c 0079 0024 001e 0078 0065 006c first byte diff 108 got ff ref d1 got: 65 01 e4 8a 9a 69 f0 99 b6 8b 60 eb aa a8 05 e6 8c 9d 1d 56 c7 aa 08 e5 82 b4 41 e7 90 98 ea b3 bc 36 72 e7 ad 84 cc bc 33 ec b2 aa 1f e6 a6 8f 06 c8 a6 6a ed 88 96 ec 9a b9 50 ec a2 81 0c eb a1 bb e5 83 90 72 68 f3 ad b1 9d f1 99 b0 85 e4 9a 95 40 24 0d 7e ea bd a9 c4 bd c7 96 f0 ab b7 9d de a2 f0 92 89 8a f2 9b 91 88 5c ff ff 6c 79 24 1e 78 65 6c aa aa ref: 65 01 e4 8a 9a 69 f0 99 b6 8b 60 eb aa a8 05 e6 8c 9d 1d 56 c7 aa 08 e5 82 b4 41 e7 90 98 ea b3 bc 36 72 e7 ad 84 cc bc 33 ec b2 aa 1f e6 a6 8f 06 c8 a6 6a ed 88 96 ec 9a b9 50 ec a2 81 0c eb a1 bb e5 83 90 72 68 f3 ad b1 9d f1 99 b0 85 e4 9a 95 40 24 0d 7e ea bd a9 c4 bd c7 96 f0 ab b7 9d de a2 f0 92 89 8a f2 9b 91 88 5c d1 a7 dd a4 6c 79 24 1e 78 65 6c --- Command finished with exit code: 0 ---

{"edits": [{"new_string": "const __m128i ascii_mask = _mm_set1_epi16((short)0xff80);\n const __m128i zero = _mm_setzero_si128();", "old_string": "const __m128i ascii_mask = _mm_set1_epi16((short)0xff80);", "replace_all": false}, {"new_string": "if (_mm_movemask_epi8(_mm_cmpeq_epi16(m, zero)) != 0xffff) break;", "old_string": "if (_mm_movemask_epi8(m) != 0) break;", "replace_all": false}, {"new_string": "if (_mm_movemask_epi8(_mm_cmpeq_epi16(m, zero)) == 0xffff) {", "old_string": "if (_mm_movemask_epi8(m) == 0) {", "replace_all": false}], "file_path": "submission/solve.c", "intent": "Fix SIMD ASCII detection for any nonzero masked bits"}

Edited submission/solve.c Applied: ✓ Edit 1: replaced 1 occurrence ✓ Edit 2: replaced 1 occurrence ✓ Edit 3: replaced 1 occurrence Total: 3 applied, 0 failed Diff: 8343+ const __m128i zero = _mm_setzero_si128(); 8353- if (_mm_movemask_epi8(m) != 0) break; 8354+ if (_mm_movemask_epi8(_mm_cmpeq_epi16(m, zero)) != 0xffff) break; 8362- if (_mm_movemask_epi8(m) == 0) { 8363+ if (_mm_movemask_epi8(_mm_cmpeq_epi16(m, zero)) == 0xffff) {

{"command": "./grade --seed 1", "intent": "Grade corrected SIMD detector", "notify": true, "run_in_background": true, "timeout": 1200000, "wake": true}

Command started in background. Task ID: 745487zz62 Name: Grade corrected SIMD detecto Output file: /tmp/jcode-bg-tasks/745487zz62.output Status file: /tmp/jcode-bg-tasks/745487zz62.status.json The agent will be woken when the task completes. To wait for completion/checkpoints: use the `bg` tool with action="wait" and task_id="745487zz62" To check progress immediately: use the `bg` tool with action="status" and task_id="745487zz62" To see output: use the `read` tool on the output file, or `bg` with action="output"

{"action": "wait", "dry_run": null, "graceful_timeout_ms": null, "include_output_preview": true, "intent": "Wait for grade", "latest": false, "lines": null, "max_age_hours": null, "max_wait_seconds": 120, "notify": null, "return_on_progress": false, "session_only": true, "status_filter": null, "tail_lines": 80, "task_id": "745487zz62", "task_ids": null, "wait_mode": "any", "wake": null}

Background task finished. Task: 745487zz62 Name: Grade corrected SIMD detecto Tool: bash Status: completed Session: session_cactus_1784428616358_ad1e0a14fe6acb8b Started: 2026-07-19T02:39:05.487855813+00:00 Completed: 2026-07-19T02:39:09.404033201+00:00 Duration: 3.92s Exit code: 0 Notify: true Wake: true Recent events: - Completed · 2026-07-19T02:39:09.404053459+00:00 Output preview: ```text build 0.7s verify 2.5s PASS measure 0.7s 45,635,919 instructions (given: 78,181,481) SCORE +0.7767 (1.713x) --- Command finished with exit code: 0 --- ```

{"command": "callgrind_annotate --auto=yes --threshold=99 .build/callgrind.runner.out | sed -n '1,220p'", "intent": "Inspect instruction hotspots in current implementation", "notify": false, "run_in_background": false, "timeout": 120000, "wake": false}

-------------------------------------------------------------------------------- Profile data file '.build/callgrind.runner.out' (creator: callgrind-3.25.1) -------------------------------------------------------------------------------- I1 cache: D1 cache: LL cache: Timerange: Basic block 0 - 1750783 Trigger: Program termination Profiled target: /tmp/jcode-bench/20260719T023555Z-jcode-solo-gpt-5.5-utf16-transcode/tasks/utf16-transcode/.build/runner /tmp/jcode-bench/20260719T023555Z-jcode-solo-gpt-5.5-utf16-transcode/tasks/utf16-transcode/.build/corpus_1.bin (PID 295, part 1) Events recorded: Ir Events shown: Ir Event sort order: Ir Thresholds: 99 Include dirs: User annotated: Auto-annotation: on -------------------------------------------------------------------------------- Ir -------------------------------------------------------------------------------- 8,652,540 (100.0%) PROGRAM TOTALS -------------------------------------------------------------------------------- Ir file:function -------------------------------------------------------------------------------- 8,131,747 (93.98%) submission/solve.c:utf16_to_utf8 [/tmp/jcode-bench/20260719T023555Z-jcode-solo-gpt-5.5-utf16-transcode/tasks/utf16-transcode/.build/runner] 520,793 ( 6.02%) /usr/lib/gcc/x86_64-pc-linux-gnu/16/include/emmintrin.h:utf16_to_utf8 -------------------------------------------------------------------------------- -- Auto-annotated source: submission/solve.c -------------------------------------------------------------------------------- Ir . #include <stdint.h> . #include <stddef.h> . #include <string.h> . #include <emmintrin.h> . . #define INVALID ((size_t)-1) . . static inline void store32(uint8_t *p, uint32_t v) { 322,969 ( 3.73%) memcpy(p, &v, 4); . } . . static const uint32_t u8tab[65536] = { . 0x01000000u, 0x01000001u, 0x01000002u, 0x01000003u, 0x01000004u, 0x01000005u, 0x01000006u, 0x01000007u, . 0x01000008u, 0x01000009u, 0x0100000au, 0x0100000bu, 0x0100000cu, 0x0100000du, 0x0100000eu, 0x0100000fu, . 0x01000010u, 0x01000011u, 0x01000012u, 0x01000013u, 0x01000014u, 0x01000015u, 0x01000016u, 0x01000017u, . 0x01000018u, 0x01000019u, 0x0100001au, 0x0100001bu, 0x0100001cu, 0x0100001du, 0x0100001eu, 0x0100001fu, . 0x01000020u, 0x01000021u, 0x01000022u, 0x01000023u, 0x01000024u, 0x01000025u, 0x01000026u, 0x01000027u, -- line 17 ---------------------------------------- -- line 8330 ---------------------------------------- . 0x008084f4u, 0x009084f4u, 0x00a084f4u, 0x00b084f4u, 0x008085f4u, 0x009085f4u, 0x00a085f4u, 0x00b085f4u, . 0x008086f4u, 0x009086f4u, 0x00a086f4u, 0x00b086f4u, 0x008087f4u, 0x009087f4u, 0x00a087f4u, 0x00b087f4u, . 0x008088f4u, 0x009088f4u, 0x00a088f4u, 0x00b088f4u, 0x008089f4u, 0x009089f4u, 0x00a089f4u, 0x00b089f4u, . 0x00808af4u, 0x00908af4u, 0x00a08af4u, 0x00b08af4u, 0x00808bf4u, 0x00908bf4u, 0x00a08bf4u, 0x00b08bf4u, . 0x00808cf4u, 0x00908cf4u, 0x00a08cf4u, 0x00b08cf4u, 0x00808df4u, 0x00908df4u, 0x00a08df4u, 0x00b08df4u, . 0x00808ef4u, 0x00908ef4u, 0x00a08ef4u, 0x00b08ef4u, 0x00808ff4u, 0x00908ff4u, 0x00a08ff4u, 0x00b08ff4u, . }; . 1,184 ( 0.01%) size_t utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out) { . const uint16_t *p = in; 592 ( 0.01%) const uint16_t *end = in + n; 592 ( 0.01%) uint8_t *q = out; . const __m128i ascii_mask = _mm_set1_epi16((short)0xff80); . const __m128i zero = _mm_setzero_si128(); . 795,100 ( 9.19%) while (p < end) { 1,515,231 (17.51%) uint32_t c = *p++; 794,556 ( 9.18%) if (c < 0x80) { 44,244 ( 0.51%) *q++ = (uint8_t)c; . 142,984 ( 1.65%) while ((size_t)(end - p) >= 16) { . __m128i a = _mm_loadu_si128((const __m128i *)(const void *)p); . __m128i b = _mm_loadu_si128((const __m128i *)(const void *)(p + 8)); . __m128i m = _mm_or_si128(_mm_and_si128(a, ascii_mask), _mm_and_si128(b, ascii_mask)); 98,134 ( 1.13%) if (_mm_movemask_epi8(_mm_cmpeq_epi16(m, zero)) != 0xffff) break; . __m128i packed = _mm_packus_epi16(a, b); . _mm_storeu_si128((__m128i *)(void *)q, packed); 55,174 ( 0.64%) p += 16; 55,174 ( 0.64%) q += 16; . } 1,072 ( 0.01%) if ((size_t)(end - p) >= 8) { . __m128i a = _mm_loadu_si128((const __m128i *)(const void *)p); . __m128i m = _mm_and_si128(a, ascii_mask); 86,784 ( 1.00%) if (_mm_movemask_epi8(_mm_cmpeq_epi16(m, zero)) == 0xffff) { . __m128i packed = _mm_packus_epi16(a, a); . _mm_storel_epi64((__m128i *)(void *)q, packed); 5,651 ( 0.07%) p += 8; 11,302 ( 0.13%) q += 8; . } . } 249,036 ( 2.88%) while (p < end) { 91,393 ( 1.06%) c = *p; 182,786 ( 2.11%) if (c >= 0x80) break; 139,610 ( 1.61%) *q++ = (uint8_t)c; 69,805 ( 0.81%) p++; . } . continue; . } . 375,370 ( 4.34%) uint32_t sx = c - 0xD800u; 750,740 ( 8.68%) if (sx >= 0x800u) { 646,530 ( 7.47%) uint32_t v = u8tab[c]; . store32(q, v); 645,938 ( 7.47%) q += v >> 24; 104,802 ( 1.21%) } else if (sx < 0x400u) { 104,802 ( 1.21%) if (p >= end) return INVALID; 52,401 ( 0.61%) uint32_t lo = *p; 52,401 ( 0.61%) uint32_t sy = lo - 0xDC00u; 104,802 ( 1.21%) if (sy >= 0x400u) return INVALID; 52,401 ( 0.61%) p++; 472,201 ( 5.46%) uint32_t v = hitab[sx] | ((sy >> 6) << 16) | ((0x80u | (sy & 0x3fu)) << 24); . store32(q, v); 104,802 ( 1.21%) q += 4; . } else { . return INVALID; . } . } 1,184 ( 0.01%) return (size_t)(q - out); . } -------------------------------------------------------------------------------- -- Auto-annotated source: /usr/lib/gcc/x86_64-pc-linux-gnu/16/include/emmintrin.h -------------------------------------------------------------------------------- Ir -- line 699 ---------------------------------------- . _mm_load_si128 (__m128i const *__P) . { . return *__P; . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_loadu_si128 (__m128i_u const *__P) . { 119,830 ( 1.38%) return *__P; . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_loadl_epi64 (__m128i_u const *__P) . { . return _mm_set_epi64 ((__m64)0LL, *(__m64_u *)__P); . } . -- line 715 ---------------------------------------- -- line 735 ---------------------------------------- . _mm_store_si128 (__m128i *__P, __m128i __B) . { . *__P = __B; . } . . extern __inline void __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_storeu_si128 (__m128i_u *__P, __m128i __B) . { 27,587 ( 0.32%) *__P = __B; . } . . extern __inline void __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_storel_epi64 (__m128i_u *__P, __m128i __B) . { 5,651 ( 0.07%) *(__m64_u *)__P = (__m64) ((__v2di)__B)[0]; . } . . extern __inline void __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_storeu_si64 (void *__P, __m128i __B) . { . _mm_storel_epi64 ((__m128i_u *)__P, __B); . } . -- line 757 ---------------------------------------- -- line 999 ---------------------------------------- . _mm_packs_epi32 (__m128i __A, __m128i __B) . { . return (__m128i)__builtin_ia32_packssdw128 ((__v4si)__A, (__v4si)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_packus_epi16 (__m128i __A, __m128i __B) . { 33,238 ( 0.38%) return (__m128i)__builtin_ia32_packuswb128 ((__v8hi)__A, (__v8hi)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_unpackhi_epi8 (__m128i __A, __m128i __B) . { . return (__m128i)__builtin_ia32_punpckhbw128 ((__v16qi)__A, (__v16qi)__B); . } . -- line 1015 ---------------------------------------- -- line 1310 ---------------------------------------- . _mm_srl_epi64 (__m128i __A, __m128i __B) . { . return (__m128i)__builtin_ia32_psrlq128 ((__v2di)__A, (__v2di)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_and_si128 (__m128i __A, __m128i __B) . { 43,392 ( 0.50%) return (__m128i) ((__v2du)__A & (__v2du)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_andnot_si128 (__m128i __A, __m128i __B) . { . return (__m128i)__builtin_ia32_pandn128 ((__v2di)__A, (__v2di)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_or_si128 (__m128i __A, __m128i __B) . { 148,977 ( 1.72%) return (__m128i) ((__v2du)__A | (__v2du)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_xor_si128 (__m128i __A, __m128i __B) . { . return (__m128i) ((__v2du)__A ^ (__v2du)__B); . } . --- Command finished with exit code: 0 ---

{"edits": [{"new_string": "#include <emmintrin.h>", "old_string": "#include <string.h>\n#include <emmintrin.h>", "replace_all": false}, {"new_string": "typedef uint32_t unaligned_u32 __attribute__((__may_alias__, __aligned__(1)));\n\nstatic inline void store32(uint8_t *p, uint32_t v) {\n *(unaligned_u32 *)(void *)p = v;\n}", "old_string": "static inline void store32(uint8_t *p, uint32_t v) {\n memcpy(p, &v, 4);\n}", "replace_all": false}], "file_path": "submission/solve.c", "intent": "Use direct unaligned may_alias stores instead of memcpy"}

Edited submission/solve.c Applied: ✓ Edit 1: replaced 1 occurrence ✓ Edit 2: replaced 1 occurrence Total: 2 applied, 0 failed Diff: 3- #include <string.h> 7+ typedef uint32_t unaligned_u32 __attribute__((__may_alias__, __aligned__(1))); 9- memcpy(p, &v, 4); 10+ *(unaligned_u32 *)(void *)p = v;

{"command": "./grade --seed 1", "intent": "Grade direct-store variant", "notify": true, "run_in_background": true, "timeout": 1200000, "wake": true}

Command started in background. Task ID: 758233edb1 Name: Grade direct-store variant Output file: /tmp/jcode-bg-tasks/758233edb1.output Status file: /tmp/jcode-bg-tasks/758233edb1.status.json The agent will be woken when the task completes. To wait for completion/checkpoints: use the `bg` tool with action="wait" and task_id="758233edb1" To check progress immediately: use the `bg` tool with action="status" and task_id="758233edb1" To see output: use the `read` tool on the output file, or `bg` with action="output"

{"action": "wait", "dry_run": null, "graceful_timeout_ms": null, "include_output_preview": true, "intent": "Wait for direct-store grade", "latest": false, "lines": null, "max_age_hours": null, "max_wait_seconds": 120, "notify": null, "return_on_progress": false, "session_only": true, "status_filter": null, "tail_lines": 80, "task_id": "758233edb1", "task_ids": null, "wait_mode": "any", "wake": null}

Background task finished. Task: 758233edb1 Name: Grade direct-store variant Tool: bash Status: completed Session: session_cactus_1784428616358_ad1e0a14fe6acb8b Started: 2026-07-19T02:39:18.233776631+00:00 Completed: 2026-07-19T02:39:21.593206943+00:00 Duration: 3.36s Exit code: 0 Notify: true Wake: true Recent events: - Completed · 2026-07-19T02:39:21.593226013+00:00 Output preview: ```text build 0.7s verify 2.5s PASS measure 0.2s 45,635,919 instructions (given: 78,181,481) SCORE +0.7767 (1.713x) --- Command finished with exit code: 0 --- ```

{"file_path": "submission/solve.c", "intent": "Add SSSE3 include for byte shuffle", "new_string": "#include <emmintrin.h>\n#include <tmmintrin.h>", "old_string": "#include <emmintrin.h>", "replace_all": false}

Edited submission/solve.c: replaced 1 occurrence(s) 3- #include <emmintrin.h> 3+ #include <emmintrin.h> 4+ #include <tmmintrin.h> Context after edit (lines 1-7): 1│ #include <stdint.h> 2│ #include <stddef.h> 3│ #include <emmintrin.h> 4│ #include <tmmintrin.h> 5│ 6│ #define INVALID ((size_t)-1) 7│

{"file": null, "glob": null, "intent": "Locate function declaration after tables", "max_files": 5, "max_regions": 5, "mode": "grep", "path": "submission/solve.c", "paths_only": false, "query": "size_t utf16_to_utf8", "regex": false, "terms": null, "type": "c"}

query: size_t utf16_to_utf8 matches: 1 in 1 files solve.c symbols: no structural items detected - <file scope> - @ 8340 size_t utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out) {

{"file_path": "submission/solve.c", "intent": "Read area around function start for patch", "limit": 80, "start_line": 8334}

8334 0x008088f4u, 0x009088f4u, 0x00a088f4u, 0x00b088f4u, 0x008089f4u, 0x009089f4u, 0x00a089f4u, 0x00b089f4u, 8335 0x00808af4u, 0x00908af4u, 0x00a08af4u, 0x00b08af4u, 0x00808bf4u, 0x00908bf4u, 0x00a08bf4u, 0x00b08bf4u, 8336 0x00808cf4u, 0x00908cf4u, 0x00a08cf4u, 0x00b08cf4u, 0x00808df4u, 0x00908df4u, 0x00a08df4u, 0x00b08df4u, 8337 0x00808ef4u, 0x00908ef4u, 0x00a08ef4u, 0x00b08ef4u, 0x00808ff4u, 0x00908ff4u, 0x00a08ff4u, 0x00b08ff4u, 8338 }; 8339 8340 size_t utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out) { 8341 const uint16_t *p = in; 8342 const uint16_t *end = in + n; 8343 uint8_t *q = out; 8344 const __m128i ascii_mask = _mm_set1_epi16((short)0xff80); 8345 const __m128i zero = _mm_setzero_si128(); 8346 8347 while (p < end) { 8348 uint32_t c = *p++; 8349 if (c < 0x80) { 8350 *q++ = (uint8_t)c; 8351 8352 while ((size_t)(end - p) >= 16) { 8353 __m128i a = _mm_loadu_si128((const __m128i *)(const void *)p); 8354 __m128i b = _mm_loadu_si128((const __m128i *)(const void *)(p + 8)); 8355 __m128i m = _mm_or_si128(_mm_and_si128(a, ascii_mask), _mm_and_si128(b, ascii_mask)); 8356 if (_mm_movemask_epi8(_mm_cmpeq_epi16(m, zero)) != 0xffff) break; 8357 __m128i packed = _mm_packus_epi16(a, b); 8358 _mm_storeu_si128((__m128i *)(void *)q, packed); 8359 p += 16; 8360 q += 16; 8361 } 8362 if ((size_t)(end - p) >= 8) { 8363 __m128i a = _mm_loadu_si128((const __m128i *)(const void *)p); 8364 __m128i m = _mm_and_si128(a, ascii_mask); 8365 if (_mm_movemask_epi8(_mm_cmpeq_epi16(m, zero)) == 0xffff) { 8366 __m128i packed = _mm_packus_epi16(a, a); 8367 _mm_storel_epi64((__m128i *)(void *)q, packed); 8368 p += 8; 8369 q += 8; 8370 } 8371 } 8372 while (p < end) { 8373 c = *p; 8374 if (c >= 0x80) break; 8375 *q++ = (uint8_t)c; 8376 p++; 8377 } 8378 continue; 8379 } 8380 8381 uint32_t sx = c - 0xD800u; 8382 if (sx >= 0x800u) { 8383 uint32_t v = u8tab[c]; 8384 store32(q, v); 8385 q += v >> 24; 8386 } else if (sx < 0x400u) { 8387 if (p >= end) return INVALID; 8388 uint32_t lo = *p; 8389 uint32_t sy = lo - 0xDC00u; 8390 if (sy >= 0x400u) return INVALID; 8391 p++; 8392 uint32_t v = hitab[sx] | ((sy >> 6) << 16) | ((0x80u | (sy & 0x3fu)) << 24); 8393 store32(q, v); 8394 q += 4; 8395 } else { 8396 return INVALID; 8397 } 8398 } 8399 return (size_t)(q - out); 8400 }

{"file_path": "submission/solve.c", "intent": "Add shuffle masks and SSSE3 target attribute", "new_string": "};\n\nstatic const uint8_t shuf3_a0[16] __attribute__((aligned(16))) = {0,8,0x80,1,9,0x80,2,10,0x80,3,11,0x80,4,12,0x80,5};\nstatic const uint8_t shuf3_c0[16] __attribute__((aligned(16))) = {0x80,0x80,0,0x80,0x80,1,0x80,0x80,2,0x80,0x80,3,0x80,0x80,4,0x80};\nstatic const uint8_t shuf3_a1[16] __attribute__((aligned(16))) = {13,0x80,6,14,0x80,7,15,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80};\nstatic const uint8_t shuf3_c1[16] __attribute__((aligned(16))) = {0x80,5,0x80,0x80,6,0x80,0x80,7,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80};\n\n__attribute__((target(\"ssse3\")))\nsize_t utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out) {", "old_string": "};\n\nsize_t utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out) {", "replace_all": false}

Edited submission/solve.c: replaced 1 occurrence(s) 8340+ static const uint8_t shuf3_a0[16] __attribute__((aligned(16))) = {0,8,0x80,1,9,0x80,2,10,0x80,3,11,0x80,4,12,0x80,5}; 8341+ static const uint8_t shuf3_c0[16] __attribute__((aligned(16))) = {0x80,0x80,0,0x80,0x80,1,0x80,0x80,2,0x80,0x80,3,0x80,0x80,4,0x80}; 8342+ static const uint8_t shuf3_a1[16] __attribute__((aligned(16))) = {13,0x80,6,14,0x80,7,15,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80}; 8343+ static const uint8_t shuf3_c1[16] __attribute__((aligned(16))) = {0x80,5,0x80,0x80,6,0x80,0x80,7,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80}; 8345+ __attribute__((target("ssse3"))) Context after edit (lines 8335-8349): 8335│ 0x00808af4u, 0x00908af4u, 0x00a08af4u, 0x00b08af4u, 0x00808bf4u, 0x00908bf4u, 0x00a08bf4u, 0x00b08bf4u, 8336│ 0x00808cf4u, 0x00908cf4u, 0x00a08cf4u, 0x00b08cf4u, 0x00808df4u, 0x00908df4u, 0x00a08df4u, 0x00b08df4u, 8337│ 0x00808ef4u, 0x00908ef4u, 0x00a08ef4u, 0x00b08ef4u, 0x00808ff4u, 0x00908ff4u, 0x00a08ff4u, 0x00b08ff4u, 8338│ }; 8339│ 8340│ static const uint8_t shuf3_a0[16] __attribute__((aligned(16))) = {0,8,0x80,1,9,0x80,2,10,0x80,3,11,0x80,4,12,0x80,5}; 8341│ static const uint8_t shuf3_c0[16] __attribute__((aligned(16))) = {0x80,0x80,0,0x80,0x80,1,0x80,0x80,2,0x80,0x80,3,0x80,0x80,4,0x80}; 8342│ static const uint8_t shuf3_a1[16] __attribute__((aligned(16))) = {13,0x80,6,14,0x80,7,15,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80}; 8343│ static const uint8_t shuf3_c1[16] __attribute__((aligned(16))) = {0x80,5,0x80,0x80,6,0x80,0x80,7,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80}; 8344│ 8345│ __attribute__((target("ssse3"))) 8346│ size_t utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out) { 8347│ const uint16_t *p = in; 8348│ const uint16_t *end = in + n; 8349│ uint8_t *q = out;

{"file_path": "submission/solve.c", "intent": "Add vector constants for BMP3 path", "new_string": "const __m128i ascii_mask = _mm_set1_epi16((short)0xff80);\n const __m128i zero = _mm_setzero_si128();\n const __m128i mask_f800 = _mm_set1_epi16((short)0xf800);\n const __m128i surr_f800 = _mm_set1_epi16((short)0xd800);\n const __m128i byte_80 = _mm_set1_epi16(0x0080);\n const __m128i byte_e0 = _mm_set1_epi16(0x00e0);\n const __m128i mask_3f = _mm_set1_epi16(0x003f);\n const __m128i ma0 = _mm_load_si128((const __m128i *)(const void *)shuf3_a0);\n const __m128i mc0 = _mm_load_si128((const __m128i *)(const void *)shuf3_c0);\n const __m128i ma1 = _mm_load_si128((const __m128i *)(const void *)shuf3_a1);\n const __m128i mc1 = _mm_load_si128((const __m128i *)(const void *)shuf3_c1);", "old_string": "const __m128i ascii_mask = _mm_set1_epi16((short)0xff80);\n const __m128i zero = _mm_setzero_si128();", "replace_all": false}

Edited submission/solve.c: replaced 1 occurrence(s) 8352- const __m128i zero = _mm_setzero_si128(); 8352+ const __m128i zero = _mm_setzero_si128(); 8353+ const __m128i mask_f800 = _mm_set1_epi16((short)0xf800); 8354+ const __m128i surr_f800 = _mm_set1_epi16((short)0xd800); 8355+ const __m128i byte_80 = _mm_set1_epi16(0x0080); 8356+ const __m128i byte_e0 = _mm_set1_epi16(0x00e0); 8357+ const __m128i mask_3f = _mm_set1_epi16(0x003f); 8358+ const __m128i ma0 = _mm_load_si128((const __m128i *)(const void *)shuf3_a0); 8359+ const __m128i mc0 = _mm_load_si128((const __m128i *)(const void *)shuf3_c0); 8360+ const __m128i ma1 = _mm_load_si128((const __m128i *)(const void *)shuf3_a1); 8361+ const __m128i mc1 = _mm_load_si128((const __m128i *)(const void *)shuf3_c1); Context after edit (lines 8348-8364): 8348│ const uint16_t *end = in + n; 8349│ uint8_t *q = out; 8350│ const __m128i ascii_mask = _mm_set1_epi16((short)0xff80); 8351│ const __m128i zero = _mm_setzero_si128(); 8352│ const __m128i mask_f800 = _mm_set1_epi16((short)0xf800); 8353│ const __m128i surr_f800 = _mm_set1_epi16((short)0xd800); 8354│ const __m128i byte_80 = _mm_set1_epi16(0x0080); 8355│ const __m128i byte_e0 = _mm_set1_epi16(0x00e0); 8356│ const __m128i mask_3f = _mm_set1_epi16(0x003f); 8357│ const __m128i ma0 = _mm_load_si128((const __m128i *)(const void *)shuf3_a0); 8358│ const __m128i mc0 = _mm_load_si128((const __m128i *)(const void *)shuf3_c0); 8359│ const __m128i ma1 = _mm_load_si128((const __m128i *)(const void *)shuf3_a1); 8360│ const __m128i mc1 = _mm_load_si128((const __m128i *)(const void *)shuf3_c1); 8361│ 8362│ while (p < end) { 8363│ uint32_t c = *p++; 8364│ if (c < 0x80) {

{"file_path": "submission/solve.c", "intent": "Add 8-wide three-byte BMP fast path", "new_string": "if (sx >= 0x800u) {\n if (c >= 0x800u) {\n const uint16_t *r = p - 1;\n while ((size_t)(end - r) >= 8) {\n __m128i vv = _mm_loadu_si128((const __m128i *)(const void *)r);\n __m128i top = _mm_and_si128(vv, mask_f800);\n __m128i bad = _mm_or_si128(_mm_cmpeq_epi16(top, zero), _mm_cmpeq_epi16(top, surr_f800));\n if (_mm_movemask_epi8(bad) != 0) break;\n\n __m128i b0 = _mm_or_si128(_mm_srli_epi16(vv, 12), byte_e0);\n __m128i b1 = _mm_or_si128(_mm_and_si128(_mm_srli_epi16(vv, 6), mask_3f), byte_80);\n __m128i b2 = _mm_or_si128(_mm_and_si128(vv, mask_3f), byte_80);\n __m128i b01 = _mm_packus_epi16(b0, b1);\n __m128i b22 = _mm_packus_epi16(b2, b2);\n __m128i o0 = _mm_or_si128(_mm_shuffle_epi8(b01, ma0), _mm_shuffle_epi8(b22, mc0));\n __m128i o1 = _mm_or_si128(_mm_shuffle_epi8(b01, ma1), _mm_shuffle_epi8(b22, mc1));\n _mm_storeu_si128((__m128i *)(void *)q, o0);\n _mm_storel_epi64((__m128i *)(void *)(q + 16), o1);\n r += 8;\n q += 24;\n }\n if (r != p - 1) {\n p = r;\n continue;\n }\n }\n uint32_t v = u8tab[c];\n store32(q, v);\n q += v >> 24;", "old_string": "if (sx >= 0x800u) {\n uint32_t v = u8tab[c];\n store32(q, v);\n q += v >> 24;", "replace_all": false}

Edited submission/solve.c: replaced 1 occurrence(s) 8399+ if (c >= 0x800u) { 8400+ const uint16_t *r = p - 1; 8401+ while ((size_t)(end - r) >= 8) { 8402+ __m128i vv = _mm_loadu_si128((const __m128i *)(const void *)r); 8403+ __m128i top = _mm_and_si128(vv, mask_f800); 8404+ __m128i bad = _mm_or_si128(_mm_cmpeq_epi16(top, zero), _mm_cmpeq_epi16(top, surr_f800)); 8405+ if (_mm_movemask_epi8(bad) != 0) break; 8407+ __m128i b0 = _mm_or_si128(_mm_srli_epi16(vv, 12), byte_e0); 8408+ __m128i b1 = _mm_or_si128(_mm_and_si128(_mm_srli_epi16(vv, 6), mask_3f), byte_80); 8409+ __m128i b2 = _mm_or_si128(_mm_and_si128(vv, mask_3f), byte_80); 8410+ __m128i b01 = _mm_packus_epi16(b0, b1); 8411+ __m128i b22 = _mm_packus_epi16(b2, b2); 8412+ __m128i o0 = _mm_or_si128(_mm_shuffle_epi8(b01, ma0), _mm_shuffle_epi8(b22, mc0)); 8413+ __m128i o1 = _mm_or_si128(_mm_shuffle_epi8(b01, ma1), _mm_shuffle_epi8(b22, mc1)); 8414+ _mm_storeu_si128((__m128i *)(void *)q, o0); 8415+ _mm_storel_epi64((__m128i *)(void *)(q + 16), o1); 8416+ r += 8; 8417+ q += 24; 8418+ } 8419+ if (r != p - 1) { 8420+ p = r; 8421+ continue; 8422+ } 8423+ } Context after edit (lines 8395-8429): 8395│ 8396│ uint32_t sx = c - 0xD800u; 8397│ if (sx >= 0x800u) { 8398│ if (c >= 0x800u) { 8399│ const uint16_t *r = p - 1; 8400│ while ((size_t)(end - r) >= 8) { 8401│ __m128i vv = _mm_loadu_si128((const __m128i *)(const void *)r); 8402│ __m128i top = _mm_and_si128(vv, mask_f800); 8403│ __m128i bad = _mm_or_si128(_mm_cmpeq_epi16(top, zero), _mm_cmpeq_epi16(top, surr_f800)); 8404│ if (_mm_movemask_epi8(bad) != 0) break; 8405│ 8406│ __m128i b0 = _mm_or_si128(_mm_srli_epi16(vv, 12), byte_e0); 8407│ __m128i b1 = _mm_or_si128(_mm_and_si128(_mm_srli_epi16(vv, 6), mask_3f), byte_80); 8408│ __m128i b2 = _mm_or_si128(_mm_and_si128(vv, mask_3f), byte_80); 8409│ __m128i b01 = _mm_packus_epi16(b0, b1); 8410│ __m128i b22 = _mm_packus_epi16(b2, b2); 8411│ __m128i o0 = _mm_or_si128(_mm_shuffle_epi8(b01, ma0), _mm_shuffle_epi8(b22, mc0)); 8412│ __m128i o1 = _mm_or_si128(_mm_shuffle_epi8(b01, ma1), _mm_shuffle_epi8(b22, mc1)); 8413│ _mm_storeu_si128((__m128i *)(void *)q, o0); 8414│ _mm_storel_epi64((__m128i *)(void *)(q + 16), o1); 8415│ r += 8; 8416│ q += 24; 8417│ } 8418│ if (r != p - 1) { 8419│ p = r; 8420│ continue; 8421│ } 8422│ } 8423│ uint32_t v = u8tab[c]; 8424│ store32(q, v); 8425│ q += v >> 24; 8426│ } else if (sx < 0x400u) { 8427│ if (p >= end) return INVALID; 8428│ uint32_t lo = *p; 8429│ uint32_t sy = lo - 0xDC00u;

{"command": "./grade --seed 1", "intent": "Grade SSSE3 three-byte vector path", "notify": true, "run_in_background": true, "timeout": 1200000, "wake": true}

Command started in background. Task ID: 8102377g0v Name: Grade SSSE3 three-byte vecto Output file: /tmp/jcode-bg-tasks/8102377g0v.output Status file: /tmp/jcode-bg-tasks/8102377g0v.status.json The agent will be woken when the task completes. To wait for completion/checkpoints: use the `bg` tool with action="wait" and task_id="8102377g0v" To check progress immediately: use the `bg` tool with action="status" and task_id="8102377g0v" To see output: use the `read` tool on the output file, or `bg` with action="output"

{"action": "wait", "dry_run": null, "graceful_timeout_ms": null, "include_output_preview": true, "intent": "Wait for SSSE3 grade", "latest": false, "lines": null, "max_age_hours": null, "max_wait_seconds": 120, "notify": null, "return_on_progress": false, "session_only": true, "status_filter": null, "tail_lines": 100, "task_id": "8102377g0v", "task_ids": null, "wait_mode": "any", "wake": null}

Background task was already finished. Task: 8102377g0v Name: Grade SSSE3 three-byte vecto Tool: bash Status: completed Session: session_cactus_1784428616358_ad1e0a14fe6acb8b Started: 2026-07-19T02:40:10.237409695+00:00 Completed: 2026-07-19T02:40:13.596916157+00:00 Duration: 3.36s Exit code: 0 Notify: true Wake: true Recent events: - Completed · 2026-07-19T02:40:13.596951181+00:00 Output preview: ```text build 0.7s verify 2.5s PASS measure 0.2s 39,567,315 instructions (given: 78,181,481) SCORE +0.9825 (1.976x) --- Command finished with exit code: 0 --- ```

{"file_path": "submission/solve.c", "intent": "Add constant for two-byte vector path", "new_string": "const __m128i byte_80 = _mm_set1_epi16(0x0080);\n const __m128i byte_c0 = _mm_set1_epi16(0x00c0);\n const __m128i byte_e0 = _mm_set1_epi16(0x00e0);", "old_string": "const __m128i byte_80 = _mm_set1_epi16(0x0080);\n const __m128i byte_e0 = _mm_set1_epi16(0x00e0);", "replace_all": false}

Edited submission/solve.c: replaced 1 occurrence(s) 8356+ const __m128i byte_c0 = _mm_set1_epi16(0x00c0); Context after edit (lines 8352-8360): 8352│ const __m128i mask_f800 = _mm_set1_epi16((short)0xf800); 8353│ const __m128i surr_f800 = _mm_set1_epi16((short)0xd800); 8354│ const __m128i byte_80 = _mm_set1_epi16(0x0080); 8355│ const __m128i byte_c0 = _mm_set1_epi16(0x00c0); 8356│ const __m128i byte_e0 = _mm_set1_epi16(0x00e0); 8357│ const __m128i mask_3f = _mm_set1_epi16(0x003f); 8358│ const __m128i ma0 = _mm_load_si128((const __m128i *)(const void *)shuf3_a0); 8359│ const __m128i mc0 = _mm_load_si128((const __m128i *)(const void *)shuf3_c0); 8360│ const __m128i ma1 = _mm_load_si128((const __m128i *)(const void *)shuf3_a1);

{"file_path": "submission/solve.c", "intent": "Insert 8-wide two-byte vector fast path", "new_string": "if (sx >= 0x800u) {\n if (c < 0x800u) {\n const uint16_t *r = p - 1;\n while ((size_t)(end - r) >= 8) {\n __m128i vv = _mm_loadu_si128((const __m128i *)(const void *)r);\n __m128i top = _mm_and_si128(vv, mask_f800);\n __m128i hi = _mm_and_si128(vv, ascii_mask);\n if (_mm_movemask_epi8(_mm_cmpeq_epi16(top, zero)) != 0xffff) break;\n if (_mm_movemask_epi8(_mm_cmpeq_epi16(hi, zero)) != 0) break;\n __m128i b0 = _mm_or_si128(_mm_srli_epi16(vv, 6), byte_c0);\n __m128i b1 = _mm_or_si128(_mm_and_si128(vv, mask_3f), byte_80);\n __m128i p0 = _mm_packus_epi16(b0, b0);\n __m128i p1 = _mm_packus_epi16(b1, b1);\n __m128i oo = _mm_unpacklo_epi8(p0, p1);\n _mm_storeu_si128((__m128i *)(void *)q, oo);\n r += 8;\n q += 16;\n }\n if (r != p - 1) {\n p = r;\n continue;\n }\n } else if (c >= 0x800u) {", "old_string": "if (sx >= 0x800u) {\n if (c >= 0x800u) {", "replace_all": false}

Edited submission/solve.c: replaced 1 occurrence(s) 8400- if (c >= 0x800u) { 8400+ if (c < 0x800u) { 8401+ const uint16_t *r = p - 1; 8402+ while ((size_t)(end - r) >= 8) { 8403+ __m128i vv = _mm_loadu_si128((const __m128i *)(const void *)r); 8404+ __m128i top = _mm_and_si128(vv, mask_f800); 8405+ __m128i hi = _mm_and_si128(vv, ascii_mask); 8406+ if (_mm_movemask_epi8(_mm_cmpeq_epi16(top, zero)) != 0xffff) break; 8407+ if (_mm_movemask_epi8(_mm_cmpeq_epi16(hi, zero)) != 0) break; 8408+ __m128i b0 = _mm_or_si128(_mm_srli_epi16(vv, 6), byte_c0); 8409+ __m128i b1 = _mm_or_si128(_mm_and_si128(vv, mask_3f), byte_80); 8410+ __m128i p0 = _mm_packus_epi16(b0, b0); 8411+ __m128i p1 = _mm_packus_epi16(b1, b1); 8412+ __m128i oo = _mm_unpacklo_epi8(p0, p1); 8413+ _mm_storeu_si128((__m128i *)(void *)q, oo); 8414+ r += 8; 8415+ q += 16; 8416+ } 8417+ if (r != p - 1) { 8418+ p = r; 8419+ continue; 8420+ } 8421+ } else if (c >= 0x800u) { Context after edit (lines 8396-8424): 8396│ 8397│ uint32_t sx = c - 0xD800u; 8398│ if (sx >= 0x800u) { 8399│ if (c < 0x800u) { 8400│ const uint16_t *r = p - 1; 8401│ while ((size_t)(end - r) >= 8) { 8402│ __m128i vv = _mm_loadu_si128((const __m128i *)(const void *)r); 8403│ __m128i top = _mm_and_si128(vv, mask_f800); 8404│ __m128i hi = _mm_and_si128(vv, ascii_mask); 8405│ if (_mm_movemask_epi8(_mm_cmpeq_epi16(top, zero)) != 0xffff) break; 8406│ if (_mm_movemask_epi8(_mm_cmpeq_epi16(hi, zero)) != 0) break; 8407│ __m128i b0 = _mm_or_si128(_mm_srli_epi16(vv, 6), byte_c0); 8408│ __m128i b1 = _mm_or_si128(_mm_and_si128(vv, mask_3f), byte_80); 8409│ __m128i p0 = _mm_packus_epi16(b0, b0); 8410│ __m128i p1 = _mm_packus_epi16(b1, b1); 8411│ __m128i oo = _mm_unpacklo_epi8(p0, p1); 8412│ _mm_storeu_si128((__m128i *)(void *)q, oo); 8413│ r += 8; 8414│ q += 16; 8415│ } 8416│ if (r != p - 1) { 8417│ p = r; 8418│ continue; 8419│ } 8420│ } else if (c >= 0x800u) { 8421│ const uint16_t *r = p - 1; 8422│ while ((size_t)(end - r) >= 8) { 8423│ __m128i vv = _mm_loadu_si128((const __m128i *)(const void *)r); 8424│ __m128i top = _mm_and_si128(vv, mask_f800);

{"command": "./grade --seed 1", "intent": "Grade two-byte vector path", "notify": true, "run_in_background": true, "timeout": 1200000, "wake": true}

Command started in background. Task ID: 831636nxb0 Name: Grade two-byte vector path Output file: /tmp/jcode-bg-tasks/831636nxb0.output Status file: /tmp/jcode-bg-tasks/831636nxb0.status.json The agent will be woken when the task completes. To wait for completion/checkpoints: use the `bg` tool with action="wait" and task_id="831636nxb0" To check progress immediately: use the `bg` tool with action="status" and task_id="831636nxb0" To see output: use the `read` tool on the output file, or `bg` with action="output"

{"action": "wait", "dry_run": null, "graceful_timeout_ms": null, "include_output_preview": true, "intent": "Wait for two-byte vector grade", "latest": false, "lines": null, "max_age_hours": null, "max_wait_seconds": 120, "notify": null, "return_on_progress": false, "session_only": true, "status_filter": null, "tail_lines": 100, "task_id": "831636nxb0", "task_ids": null, "wait_mode": "any", "wake": null}

Background task finished. Task: 831636nxb0 Name: Grade two-byte vector path Tool: bash Status: completed Session: session_cactus_1784428616358_ad1e0a14fe6acb8b Started: 2026-07-19T02:40:31.636753766+00:00 Completed: 2026-07-19T02:40:35.074457169+00:00 Duration: 3.44s Exit code: 0 Notify: true Wake: true Recent events: - Completed · 2026-07-19T02:40:35.074469173+00:00 Output preview: ```text build 0.7s verify 2.5s PASS measure 0.1s 42,491,206 instructions (given: 78,181,481) SCORE +0.8797 (1.840x) --- Command finished with exit code: 0 --- ```

{"file_path": "submission/solve.c", "intent": "Revert two-byte vector fast path due score regression", "new_string": "if (sx >= 0x800u) {\n if (c >= 0x800u) {", "old_string": "if (sx >= 0x800u) {\n if (c < 0x800u) {\n const uint16_t *r = p - 1;\n while ((size_t)(end - r) >= 8) {\n __m128i vv = _mm_loadu_si128((const __m128i *)(const void *)r);\n __m128i top = _mm_and_si128(vv, mask_f800);\n __m128i hi = _mm_and_si128(vv, ascii_mask);\n if (_mm_movemask_epi8(_mm_cmpeq_epi16(top, zero)) != 0xffff) break;\n if (_mm_movemask_epi8(_mm_cmpeq_epi16(hi, zero)) != 0) break;\n __m128i b0 = _mm_or_si128(_mm_srli_epi16(vv, 6), byte_c0);\n __m128i b1 = _mm_or_si128(_mm_and_si128(vv, mask_3f), byte_80);\n __m128i p0 = _mm_packus_epi16(b0, b0);\n __m128i p1 = _mm_packus_epi16(b1, b1);\n __m128i oo = _mm_unpacklo_epi8(p0, p1);\n _mm_storeu_si128((__m128i *)(void *)q, oo);\n r += 8;\n q += 16;\n }\n if (r != p - 1) {\n p = r;\n continue;\n }\n } else if (c >= 0x800u) {", "replace_all": false}

Edited submission/solve.c: replaced 1 occurrence(s) 8400- if (c < 0x800u) { 8401- const uint16_t *r = p - 1; 8402- while ((size_t)(end - r) >= 8) { 8403- __m128i vv = _mm_loadu_si128((const __m128i *)(const void *)r); 8404- __m128i top = _mm_and_si128(vv, mask_f800); 8405- __m128i hi = _mm_and_si128(vv, ascii_mask); 8406- if (_mm_movemask_epi8(_mm_cmpeq_epi16(top, zero)) != 0xffff) break; 8407- if (_mm_movemask_epi8(_mm_cmpeq_epi16(hi, zero)) != 0) break; 8408- __m128i b0 = _mm_or_si128(_mm_srli_epi16(vv, 6), byte_c0); 8409- __m128i b1 = _mm_or_si128(_mm_and_si128(vv, mask_3f), byte_80); 8410- __m128i p0 = _mm_packus_epi16(b0, b0); 8411- __m128i p1 = _mm_packus_epi16(b1, b1); 8412- __m128i oo = _mm_unpacklo_epi8(p0, p1); 8413- _mm_storeu_si128((__m128i *)(void *)q, oo); 8414- r += 8; 8415- q += 16; 8416- } 8417- if (r != p - 1) { 8418- p = r; 8419- continue; 8420- } 8421- } else if (c >= 0x800u) { 8400+ if (c >= 0x800u) { Context after edit (lines 8396-8403): 8396│ 8397│ uint32_t sx = c - 0xD800u; 8398│ if (sx >= 0x800u) { 8399│ if (c >= 0x800u) { 8400│ const uint16_t *r = p - 1; 8401│ while ((size_t)(end - r) >= 8) { 8402│ __m128i vv = _mm_loadu_si128((const __m128i *)(const void *)r); 8403│ __m128i top = _mm_and_si128(vv, mask_f800);

{"file_path": "submission/solve.c", "intent": "Remove unused two-byte vector constant", "new_string": "const __m128i byte_80 = _mm_set1_epi16(0x0080);\n const __m128i byte_e0 = _mm_set1_epi16(0x00e0);", "old_string": "const __m128i byte_80 = _mm_set1_epi16(0x0080);\n const __m128i byte_c0 = _mm_set1_epi16(0x00c0);\n const __m128i byte_e0 = _mm_set1_epi16(0x00e0);", "replace_all": false}

Edited submission/solve.c: replaced 1 occurrence(s) 8356- const __m128i byte_c0 = _mm_set1_epi16(0x00c0); Context after edit (lines 8352-8359): 8352│ const __m128i mask_f800 = _mm_set1_epi16((short)0xf800); 8353│ const __m128i surr_f800 = _mm_set1_epi16((short)0xd800); 8354│ const __m128i byte_80 = _mm_set1_epi16(0x0080); 8355│ const __m128i byte_e0 = _mm_set1_epi16(0x00e0); 8356│ const __m128i mask_3f = _mm_set1_epi16(0x003f); 8357│ const __m128i ma0 = _mm_load_si128((const __m128i *)(const void *)shuf3_a0); 8358│ const __m128i mc0 = _mm_load_si128((const __m128i *)(const void *)shuf3_c0); 8359│ const __m128i ma1 = _mm_load_si128((const __m128i *)(const void *)shuf3_a1);

{"command": "python3 - <<'PY'\nfrom pathlib import Path\np=Path('submission/solve.c')\ns=p.read_text()\nlo=[]\nfor y in range(1024):\n lo.append(((y >> 6) << 16) | ((0x80 | (y & 0x3f)) << 24))\nlines=['static const uint32_t lotab[1024] = {']\nfor i in range(0,1024,8):\n lines.append(' '+', '.join(f'0x{x:08x}u' for x in lo[i:i+8])+',')\nlines.append('};')\ninsert='\\n'.join(lines)+'\\n\\n'\nmarker='static const uint8_t shuf3_a0[16]'\nif 'static const uint32_t lotab[1024]' not in s:\n s=s.replace(marker, insert+marker, 1)\ns=s.replace('uint32_t v = hitab[sx] | ((sy >> 6) << 16) | ((0x80u | (sy & 0x3fu)) << 24);','uint32_t v = hitab[sx] | lotab[sy];')\np.write_text(s)\nPY\ngrep -n \"lotab\\|hitab\\[sx\\]\" submission/solve.c | head", "intent": "Add low-surrogate table and use it", "notify": false, "run_in_background": false, "timeout": 120000, "wake": false}

8340:static const uint32_t lotab[1024] = { 8563: uint32_t v = hitab[sx] | lotab[sy]; --- Command finished with exit code: 0 ---

{"command": "./grade --seed 1", "intent": "Grade low-surrogate table variant", "notify": true, "run_in_background": true, "timeout": 1200000, "wake": true}

Command started in background. Task ID: 8548798ses Name: Grade low-surrogate table va Output file: /tmp/jcode-bg-tasks/8548798ses.output Status file: /tmp/jcode-bg-tasks/8548798ses.status.json The agent will be woken when the task completes. To wait for completion/checkpoints: use the `bg` tool with action="wait" and task_id="8548798ses" To check progress immediately: use the `bg` tool with action="status" and task_id="8548798ses" To see output: use the `read` tool on the output file, or `bg` with action="output"

{"action": "wait", "dry_run": null, "graceful_timeout_ms": null, "include_output_preview": true, "intent": "Wait for low-surrogate table grade", "latest": false, "lines": null, "max_age_hours": null, "max_wait_seconds": 120, "notify": null, "return_on_progress": false, "session_only": true, "status_filter": null, "tail_lines": 100, "task_id": "8548798ses", "task_ids": null, "wait_mode": "any", "wake": null}

Background task finished. Task: 8548798ses Name: Grade low-surrogate table va Tool: bash Status: completed Session: session_cactus_1784428616358_ad1e0a14fe6acb8b Started: 2026-07-19T02:40:54.879973170+00:00 Completed: 2026-07-19T02:40:58.360284005+00:00 Duration: 3.48s Exit code: 0 Notify: true Wake: true Recent events: - Completed · 2026-07-19T02:40:58.360307169+00:00 Output preview: ```text build 0.7s verify 2.6s PASS measure 0.2s 38,856,532 instructions (given: 78,181,481) SCORE +1.0087 (2.012x) --- Command finished with exit code: 0 --- ```

{"command": "callgrind_annotate --auto=yes --threshold=99 .build/callgrind.runner.out | sed -n '1,240p'", "intent": "Profile current +1.0 implementation", "notify": false, "run_in_background": false, "timeout": 120000, "wake": false}

-------------------------------------------------------------------------------- Profile data file '.build/callgrind.runner.out' (creator: callgrind-3.25.1) -------------------------------------------------------------------------------- I1 cache: D1 cache: LL cache: Timerange: Basic block 0 - 1543268 Trigger: Program termination Profiled target: /tmp/jcode-bench/20260719T023555Z-jcode-solo-gpt-5.5-utf16-transcode/tasks/utf16-transcode/.build/runner /tmp/jcode-bench/20260719T023555Z-jcode-solo-gpt-5.5-utf16-transcode/tasks/utf16-transcode/.build/corpus_1.bin (PID 470, part 1) Events recorded: Ir Events shown: Ir Event sort order: Ir Thresholds: 99 Include dirs: User annotated: Auto-annotation: on -------------------------------------------------------------------------------- Ir -------------------------------------------------------------------------------- 7,351,349 (100.0%) PROGRAM TOTALS -------------------------------------------------------------------------------- Ir file:function -------------------------------------------------------------------------------- 5,646,814 (76.81%) submission/solve.c:utf16_to_utf8 [/tmp/jcode-bench/20260719T023555Z-jcode-solo-gpt-5.5-utf16-transcode/tasks/utf16-transcode/.build/runner] 1,572,223 (21.39%) /usr/lib/gcc/x86_64-pc-linux-gnu/16/include/emmintrin.h:utf16_to_utf8 132,312 ( 1.80%) /usr/lib/gcc/x86_64-pc-linux-gnu/16/include/tmmintrin.h:utf16_to_utf8 -------------------------------------------------------------------------------- -- Auto-annotated source: /usr/lib/gcc/x86_64-pc-linux-gnu/16/include/tmmintrin.h -------------------------------------------------------------------------------- Ir -- line 130 ---------------------------------------- . _mm_mulhrs_pi16 (__m64 __X, __m64 __Y) . { . return (__m64) __builtin_ia32_pmulhrsw ((__v4hi)__X, (__v4hi)__Y); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_shuffle_epi8 (__m128i __X, __m128i __Y) . { 132,312 ( 1.80%) return (__m128i) __builtin_ia32_pshufb128 ((__v16qi)__X, (__v16qi)__Y); . } . . extern __inline __m64 __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_shuffle_pi8 (__m64 __X, __m64 __Y) . { . return (__m64) __builtin_ia32_pshufb ((__v8qi)__X, (__v8qi)__Y); . } . -- line 146 ---------------------------------------- -------------------------------------------------------------------------------- -- Auto-annotated source: submission/solve.c -------------------------------------------------------------------------------- Ir -- line 3 ---------------------------------------- . #include <emmintrin.h> . #include <tmmintrin.h> . . #define INVALID ((size_t)-1) . . typedef uint32_t unaligned_u32 __attribute__((__may_alias__, __aligned__(1))); . . static inline void store32(uint8_t *p, uint32_t v) { 203,690 ( 2.77%) *(unaligned_u32 *)(void *)p = v; . } . . static const uint32_t u8tab[65536] = { . 0x01000000u, 0x01000001u, 0x01000002u, 0x01000003u, 0x01000004u, 0x01000005u, 0x01000006u, 0x01000007u, . 0x01000008u, 0x01000009u, 0x0100000au, 0x0100000bu, 0x0100000cu, 0x0100000du, 0x0100000eu, 0x0100000fu, . 0x01000010u, 0x01000011u, 0x01000012u, 0x01000013u, 0x01000014u, 0x01000015u, 0x01000016u, 0x01000017u, . 0x01000018u, 0x01000019u, 0x0100001au, 0x0100001bu, 0x0100001cu, 0x0100001du, 0x0100001eu, 0x0100001fu, . 0x01000020u, 0x01000021u, 0x01000022u, 0x01000023u, 0x01000024u, 0x01000025u, 0x01000026u, 0x01000027u, -- line 19 ---------------------------------------- -- line 8469 ---------------------------------------- . }; . . static const uint8_t shuf3_a0[16] __attribute__((aligned(16))) = {0,8,0x80,1,9,0x80,2,10,0x80,3,11,0x80,4,12,0x80,5}; . static const uint8_t shuf3_c0[16] __attribute__((aligned(16))) = {0x80,0x80,0,0x80,0x80,1,0x80,0x80,2,0x80,0x80,3,0x80,0x80,4,0x80}; . static const uint8_t shuf3_a1[16] __attribute__((aligned(16))) = {13,0x80,6,14,0x80,7,15,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80}; . static const uint8_t shuf3_c1[16] __attribute__((aligned(16))) = {0x80,5,0x80,0x80,6,0x80,0x80,7,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80}; . . __attribute__((target("ssse3"))) 592 ( 0.01%) size_t utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out) { . const uint16_t *p = in; 592 ( 0.01%) const uint16_t *end = in + n; 592 ( 0.01%) uint8_t *q = out; . const __m128i ascii_mask = _mm_set1_epi16((short)0xff80); . const __m128i zero = _mm_setzero_si128(); . const __m128i mask_f800 = _mm_set1_epi16((short)0xf800); . const __m128i surr_f800 = _mm_set1_epi16((short)0xd800); . const __m128i byte_80 = _mm_set1_epi16(0x0080); . const __m128i byte_e0 = _mm_set1_epi16(0x00e0); . const __m128i mask_3f = _mm_set1_epi16(0x003f); . const __m128i ma0 = _mm_load_si128((const __m128i *)(const void *)shuf3_a0); . const __m128i mc0 = _mm_load_si128((const __m128i *)(const void *)shuf3_c0); . const __m128i ma1 = _mm_load_si128((const __m128i *)(const void *)shuf3_a1); . const __m128i mc1 = _mm_load_si128((const __m128i *)(const void *)shuf3_c1); . 459,568 ( 6.25%) while (p < end) { 610,741 ( 8.31%) uint32_t c = *p++; 459,024 ( 6.24%) if (c < 0x80) { 44,244 ( 0.60%) *q++ = (uint8_t)c; . 142,806 ( 1.94%) while ((size_t)(end - p) >= 16) { . __m128i a = _mm_loadu_si128((const __m128i *)(const void *)p); . __m128i b = _mm_loadu_si128((const __m128i *)(const void *)(p + 8)); . __m128i m = _mm_or_si128(_mm_and_si128(a, ascii_mask), _mm_and_si128(b, ascii_mask)); 98,134 ( 1.33%) if (_mm_movemask_epi8(_mm_cmpeq_epi16(m, zero)) != 0xffff) break; . __m128i packed = _mm_packus_epi16(a, b); . _mm_storeu_si128((__m128i *)(void *)q, packed); 55,174 ( 0.75%) p += 16; 55,174 ( 0.75%) q += 16; . } 1,072 ( 0.01%) if ((size_t)(end - p) >= 8) { . __m128i a = _mm_loadu_si128((const __m128i *)(const void *)p); . __m128i m = _mm_and_si128(a, ascii_mask); 86,784 ( 1.18%) if (_mm_movemask_epi8(_mm_cmpeq_epi16(m, zero)) == 0xffff) { . __m128i packed = _mm_packus_epi16(a, a); . _mm_storel_epi64((__m128i *)(void *)q, packed); 5,651 ( 0.08%) p += 8; 16,953 ( 0.23%) q += 8; . } . } 205,296 ( 2.79%) while (p < end) { 91,393 ( 1.24%) c = *p; 182,786 ( 2.49%) if (c >= 0x80) break; 139,610 ( 1.90%) *q++ = (uint8_t)c; 69,805 ( 0.95%) p++; . } . continue; . } . 207,604 ( 2.82%) uint32_t sx = c - 0xD800u; 415,208 ( 5.65%) if (sx >= 0x800u) { 310,406 ( 4.22%) if (c >= 0x800u) { 17,971 ( 0.24%) const uint16_t *r = p - 1; 159,400 ( 2.17%) while ((size_t)(end - r) >= 8) { . __m128i vv = _mm_loadu_si128((const __m128i *)(const void *)r); . __m128i top = _mm_and_si128(vv, mask_f800); . __m128i bad = _mm_or_si128(_mm_cmpeq_epi16(top, zero), _mm_cmpeq_epi16(top, surr_f800)); 78,644 ( 1.07%) if (_mm_movemask_epi8(bad) != 0) break; . . __m128i b0 = _mm_or_si128(_mm_srli_epi16(vv, 12), byte_e0); . __m128i b1 = _mm_or_si128(_mm_and_si128(_mm_srli_epi16(vv, 6), mask_3f), byte_80); . __m128i b2 = _mm_or_si128(_mm_and_si128(vv, mask_3f), byte_80); . __m128i b01 = _mm_packus_epi16(b0, b1); . __m128i b22 = _mm_packus_epi16(b2, b2); . __m128i o0 = _mm_or_si128(_mm_shuffle_epi8(b01, ma0), _mm_shuffle_epi8(b22, mc0)); . __m128i o1 = _mm_or_si128(_mm_shuffle_epi8(b01, ma1), _mm_shuffle_epi8(b22, mc1)); . _mm_storeu_si128((__m128i *)(void *)q, o0); . _mm_storel_epi64((__m128i *)(void *)(q + 16), o1); 21,460 ( 0.29%) r += 8; 21,460 ( 0.29%) q += 24; . } 35,942 ( 0.49%) if (r != p - 1) { 7,828 ( 0.11%) p = r; . continue; . } . } 453,867 ( 6.17%) uint32_t v = u8tab[c]; . store32(q, v); 302,578 ( 4.12%) q += v >> 24; 104,802 ( 1.43%) } else if (sx < 0x400u) { 104,802 ( 1.43%) if (p >= end) return INVALID; 52,401 ( 0.71%) uint32_t lo = *p; 52,401 ( 0.71%) uint32_t sy = lo - 0xDC00u; 104,802 ( 1.43%) if (sy >= 0x400u) return INVALID; 52,401 ( 0.71%) p++; 106,578 ( 1.45%) uint32_t v = hitab[sx] | lotab[sy]; . store32(q, v); 104,802 ( 1.43%) q += 4; . } else { . return INVALID; . } . } 592 ( 0.01%) return (size_t)(q - out); 1,184 ( 0.02%) } -------------------------------------------------------------------------------- -- Auto-annotated source: /usr/lib/gcc/x86_64-pc-linux-gnu/16/include/emmintrin.h -------------------------------------------------------------------------------- Ir -- line 699 ---------------------------------------- . _mm_load_si128 (__m128i const *__P) . { . return *__P; . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_loadu_si128 (__m128i_u const *__P) . { 159,152 ( 2.16%) return *__P; . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_loadl_epi64 (__m128i_u const *__P) . { . return _mm_set_epi64 ((__m64)0LL, *(__m64_u *)__P); . } . -- line 715 ---------------------------------------- -- line 735 ---------------------------------------- . _mm_store_si128 (__m128i *__P, __m128i __B) . { . *__P = __B; . ... [1405 characters truncated for page size]

{"edits": [{"new_string": "const __m128i zero = _mm_setzero_si128();", "old_string": "const __m128i ascii_mask = _mm_set1_epi16((short)0xff80);\n const __m128i zero = _mm_setzero_si128();", "replace_all": false}, {"new_string": "__m128i m = _mm_or_si128(a, b);\n __m128i packed = _mm_packus_epi16(a, b);\n if ((_mm_movemask_epi8(packed) | _mm_movemask_epi8(m)) != 0) break;\n _mm_storeu_si128((__m128i *)(void *)q, packed);", "old_string": "__m128i m = _mm_or_si128(_mm_and_si128(a, ascii_mask), _mm_and_si128(b, ascii_mask));\n if (_mm_movemask_epi8(_mm_cmpeq_epi16(m, zero)) != 0xffff) break;\n __m128i packed = _mm_packus_epi16(a, b);\n _mm_storeu_si128((__m128i *)(void *)q, packed);", "replace_all": false}, {"new_string": "__m128i packed = _mm_packus_epi16(a, a);\n if ((_mm_movemask_epi8(packed) | _mm_movemask_epi8(a)) == 0) {\n _mm_storel_epi64((__m128i *)(void *)q, packed);", "old_string": "__m128i m = _mm_and_si128(a, ascii_mask);\n if (_mm_movemask_epi8(_mm_cmpeq_epi16(m, zero)) == 0xffff) {\n __m128i packed = _mm_packus_epi16(a, a);\n _mm_storel_epi64((__m128i *)(void *)q, packed);", "replace_all": false}], "file_path": "submission/solve.c", "intent": "Use cheaper pack-based ASCII vector detection"}

Edited submission/solve.c Applied: ✓ Edit 1: replaced 1 occurrence ✓ Edit 2: replaced 1 occurrence ✓ Edit 3: replaced 1 occurrence Total: 3 applied, 0 failed Diff: 8481- const __m128i ascii_mask = _mm_set1_epi16((short)0xff80); 8501- __m128i m = _mm_or_si128(_mm_and_si128(a, ascii_mask), _mm_and_si128(b, ascii_mask)); 8502- if (_mm_movemask_epi8(_mm_cmpeq_epi16(m, zero)) != 0xffff) break; 8500+ __m128i m = _mm_or_si128(a, b); 8502+ if ((_mm_movemask_epi8(packed) | _mm_movemask_epi8(m)) != 0) break; 8510- __m128i m = _mm_and_si128(a, ascii_mask); 8511- if (_mm_movemask_epi8(_mm_cmpeq_epi16(m, zero)) == 0xffff) { 8512- __m128i packed = _mm_packus_epi16(a, a); 8509+ __m128i packed = _mm_packus_epi16(a, a); 8510+ if ((_mm_movemask_epi8(packed) | _mm_movemask_epi8(a)) == 0) {

{"command": "./grade --seed 1", "intent": "Grade pack-based ASCII detector", "notify": true, "run_in_background": true, "timeout": 1200000, "wake": true}

Command started in background. Task ID: 8803355ltw Name: Grade pack-based ASCII detec Output file: /tmp/jcode-bg-tasks/8803355ltw.output Status file: /tmp/jcode-bg-tasks/8803355ltw.status.json The agent will be woken when the task completes. To wait for completion/checkpoints: use the `bg` tool with action="wait" and task_id="8803355ltw" To check progress immediately: use the `bg` tool with action="status" and task_id="8803355ltw" To see output: use the `read` tool on the output file, or `bg` with action="output"

{"action": "wait", "dry_run": null, "graceful_timeout_ms": null, "include_output_preview": true, "intent": "Wait for pack-based ASCII grade", "latest": false, "lines": null, "max_age_hours": null, "max_wait_seconds": 120, "notify": null, "return_on_progress": false, "session_only": true, "status_filter": null, "tail_lines": 100, "task_id": "8803355ltw", "task_ids": null, "wait_mode": "any", "wake": null}

Background task finished. Task: 8803355ltw Name: Grade pack-based ASCII detec Tool: bash Status: completed Session: session_cactus_1784428616358_ad1e0a14fe6acb8b Started: 2026-07-19T02:41:20.335847403+00:00 Completed: 2026-07-19T02:41:23.761208941+00:00 Duration: 3.42s Exit code: 0 Notify: true Wake: true Recent events: - Completed · 2026-07-19T02:41:23.761246912+00:00 Output preview: ```text build 0.7s verify 2.5s PASS measure 0.2s 38,027,047 instructions (given: 78,181,481) SCORE +1.0398 (2.056x) --- Command finished with exit code: 0 --- ```

{"file_path": "submission/solve.c", "intent": "Consume short 3-byte BMP tails as scalar runs and use fixed lengths", "new_string": " if (c >= 0x800u) {\n const uint16_t *r = p - 1;\n while ((size_t)(end - r) >= 8) {\n __m128i vv = _mm_loadu_si128((const __m128i *)(const void *)r);\n __m128i top = _mm_and_si128(vv, mask_f800);\n __m128i bad = _mm_or_si128(_mm_cmpeq_epi16(top, zero), _mm_cmpeq_epi16(top, surr_f800));\n if (_mm_movemask_epi8(bad) != 0) break;\n\n __m128i b0 = _mm_or_si128(_mm_srli_epi16(vv, 12), byte_e0);\n __m128i b1 = _mm_or_si128(_mm_and_si128(_mm_srli_epi16(vv, 6), mask_3f), byte_80);\n __m128i b2 = _mm_or_si128(_mm_and_si128(vv, mask_3f), byte_80);\n __m128i b01 = _mm_packus_epi16(b0, b1);\n __m128i b22 = _mm_packus_epi16(b2, b2);\n __m128i o0 = _mm_or_si128(_mm_shuffle_epi8(b01, ma0), _mm_shuffle_epi8(b22, mc0));\n __m128i o1 = _mm_or_si128(_mm_shuffle_epi8(b01, ma1), _mm_shuffle_epi8(b22, mc1));\n _mm_storeu_si128((__m128i *)(void *)q, o0);\n _mm_storel_epi64((__m128i *)(void *)(q + 16), o1);\n r += 8;\n q += 24;\n }\n if (r != p - 1) {\n p = r;\n continue;\n }\n for (;;) {\n uint32_t v = u8tab[c];\n store32(q, v);\n q += 3;\n if (p >= end) break;\n c = *p;\n sx = c - 0xD800u;\n if (c < 0x800u || sx < 0x800u) break;\n p++;\n }\n } else {\n uint32_t v = u8tab[c];\n store32(q, v);\n q += 2;\n }", "old_string": " if (c >= 0x800u) {\n const uint16_t *r = p - 1;\n while ((size_t)(end - r) >= 8) {\n __m128i vv = _mm_loadu_si128((const __m128i *)(const void *)r);\n __m128i top = _mm_and_si128(vv, mask_f800);\n __m128i bad = _mm_or_si128(_mm_cmpeq_epi16(top, zero), _mm_cmpeq_epi16(top, surr_f800));\n if (_mm_movemask_epi8(bad) != 0) break;\n\n __m128i b0 = _mm_or_si128(_mm_srli_epi16(vv, 12), byte_e0);\n __m128i b1 = _mm_or_si128(_mm_and_si128(_mm_srli_epi16(vv, 6), mask_3f), byte_80);\n __m128i b2 = _mm_or_si128(_mm_and_si128(vv, mask_3f), byte_80);\n __m128i b01 = _mm_packus_epi16(b0, b1);\n __m128i b22 = _mm_packus_epi16(b2, b2);\n __m128i o0 = _mm_or_si128(_mm_shuffle_epi8(b01, ma0), _mm_shuffle_epi8(b22, mc0));\n __m128i o1 = _mm_or_si128(_mm_shuffle_epi8(b01, ma1), _mm_shuffle_epi8(b22, mc1));\n _mm_storeu_si128((__m128i *)(void *)q, o0);\n _mm_storel_epi64((__m128i *)(void *)(q + 16), o1);\n r += 8;\n q += 24;\n }\n if (r != p - 1) {\n p = r;\n continue;\n }\n }\n uint32_t v = u8tab[c];\n store32(q, v);\n q += v >> 24;", "replace_all": false}

Edited submission/solve.c: replaced 1 occurrence(s) 8551- } 8552- uint32_t v = u8tab[c]; 8553- store32(q, v); 8554- q += v >> 24; 8551+ for (;;) { 8552+ uint32_t v = u8tab[c]; 8553+ store32(q, v); 8554+ q += 3; 8555+ if (p >= end) break; 8556+ c = *p; 8557+ sx = c - 0xD800u; 8558+ if (c < 0x800u || sx < 0x800u) break; 8559+ p++; 8560+ } 8561+ } else { 8562+ uint32_t v = u8tab[c]; 8563+ store32(q, v); 8564+ q += 2; 8565+ } Context after edit (lines 8524-8568): 8524│ 8525│ uint32_t sx = c - 0xD800u; 8526│ if (sx >= 0x800u) { 8527│ if (c >= 0x800u) { 8528│ const uint16_t *r = p - 1; 8529│ while ((size_t)(end - r) >= 8) { 8530│ __m128i vv = _mm_loadu_si128((const __m128i *)(const void *)r); 8531│ __m128i top = _mm_and_si128(vv, mask_f800); 8532│ __m128i bad = _mm_or_si128(_mm_cmpeq_epi16(top, zero), _mm_cmpeq_epi16(top, surr_f800)); 8533│ if (_mm_movemask_epi8(bad) != 0) break; 8534│ 8535│ __m128i b0 = _mm_or_si128(_mm_srli_epi16(vv, 12), byte_e0); 8536│ __m128i b1 = _mm_or_si128(_mm_and_si128(_mm_srli_epi16(vv, 6), mask_3f), byte_80); 8537│ __m128i b2 = _mm_or_si128(_mm_and_si128(vv, mask_3f), byte_80); 8538│ __m128i b01 = _mm_packus_epi16(b0, b1); 8539│ __m128i b22 = _mm_packus_epi16(b2, b2); 8540│ __m128i o0 = _mm_or_si128(_mm_shuffle_epi8(b01, ma0), _mm_shuffle_epi8(b22, mc0)); 8541│ __m128i o1 = _mm_or_si128(_mm_shuffle_epi8(b01, ma1), _mm_shuffle_epi8(b22, mc1)); 8542│ _mm_storeu_si128((__m128i *)(void *)q, o0); 8543│ _mm_storel_epi64((__m128i *)(void *)(q + 16), o1); 8544│ r += 8; 8545│ q += 24; 8546│ } 8547│ if (r != p - 1) { 8548│ p = r; 8549│ continue; 8550│ } 8551│ for (;;) { 8552│ uint32_t v = u8tab[c]; 8553│ store32(q, v); 8554│ q += 3; 8555│ if (p >= end) break; 8556│ c = *p; 8557│ sx = c - 0xD800u; 8558│ if (c < 0x800u || sx < 0x800u) break; 8559│ p++; 8560│ } 8561│ } else { 8562│ uint32_t v = u8tab[c]; 8563│ store32(q, v); 8564│ q += 2; 8565│ } 8566│ } else if (sx < 0x400u) { 8567│ if (p >= end) return INVALID; 8568│ uint32_t lo = *p;

{"command": "./grade --seed 1", "intent": "Grade BMP run scalar-tail optimization", "notify": true, "run_in_background": true, "timeout": 1200000, "wake": true}

Command started in background. Task ID: 908573aj9o Name: Grade BMP run scalar-tail op Output file: /tmp/jcode-bg-tasks/908573aj9o.output Status file: /tmp/jcode-bg-tasks/908573aj9o.status.json The agent will be woken when the task completes. To wait for completion/checkpoints: use the `bg` tool with action="wait" and task_id="908573aj9o" To check progress immediately: use the `bg` tool with action="status" and task_id="908573aj9o" To see output: use the `read` tool on the output file, or `bg` with action="output"

{"action": "wait", "dry_run": null, "graceful_timeout_ms": null, "include_output_preview": true, "intent": "Wait for BMP run optimization grade", "latest": false, "lines": null, "max_age_hours": null, "max_wait_seconds": 120, "notify": null, "return_on_progress": false, "session_only": true, "status_filter": null, "tail_lines": 100, "task_id": "908573aj9o", "task_ids": null, "wait_mode": "any", "wake": null}

Background task finished. Task: 908573aj9o Name: Grade BMP run scalar-tail op Tool: bash Status: completed Session: session_cactus_1784428616358_ad1e0a14fe6acb8b Started: 2026-07-19T02:41:48.573967207+00:00 Completed: 2026-07-19T02:41:51.881696119+00:00 Duration: 3.31s Exit code: 0 Notify: true Wake: true Recent events: - Completed · 2026-07-19T02:41:51.881721142+00:00 Output preview: ```text build 0.7s verify 2.4s PASS measure 0.1s 35,959,032 instructions (given: 78,181,481) SCORE +1.1205 (2.174x) --- Command finished with exit code: 0 --- ```

{"file_path": "submission/solve.c", "intent": "Consume consecutive two-byte units as scalar run", "new_string": " } else {\n for (;;) {\n uint32_t v = u8tab[c];\n store32(q, v);\n q += 2;\n if (p >= end) break;\n c = *p;\n if (c < 0x80u || c >= 0x800u) break;\n p++;\n }\n }", "old_string": " } else {\n uint32_t v = u8tab[c];\n store32(q, v);\n q += 2;\n }", "replace_all": false}

Edited submission/solve.c: replaced 1 occurrence(s) 8562- uint32_t v = u8tab[c]; 8563- store32(q, v); 8564- q += 2; 8562+ for (;;) { 8563+ uint32_t v = u8tab[c]; 8564+ store32(q, v); 8565+ q += 2; 8566+ if (p >= end) break; 8567+ c = *p; 8568+ if (c < 0x80u || c >= 0x800u) break; 8569+ p++; 8570+ } Context after edit (lines 8558-8574): 8558│ if (c < 0x800u || sx < 0x800u) break; 8559│ p++; 8560│ } 8561│ } else { 8562│ for (;;) { 8563│ uint32_t v = u8tab[c]; 8564│ store32(q, v); 8565│ q += 2; 8566│ if (p >= end) break; 8567│ c = *p; 8568│ if (c < 0x80u || c >= 0x800u) break; 8569│ p++; 8570│ } 8571│ } 8572│ } else if (sx < 0x400u) { 8573│ if (p >= end) return INVALID; 8574│ uint32_t lo = *p;

{"command": "./grade --seed 1", "intent": "Grade two-byte scalar-run optimization", "notify": true, "run_in_background": true, "timeout": 1200000, "wake": true}

Command started in background. Task ID: 9178491lfp Name: Grade two-byte scalar-run op Output file: /tmp/jcode-bg-tasks/9178491lfp.output Status file: /tmp/jcode-bg-tasks/9178491lfp.status.json The agent will be woken when the task completes. To wait for completion/checkpoints: use the `bg` tool with action="wait" and task_id="9178491lfp" To check progress immediately: use the `bg` tool with action="status" and task_id="9178491lfp" To see output: use the `read` tool on the output file, or `bg` with action="output"

{"action": "wait", "dry_run": null, "graceful_timeout_ms": null, "include_output_preview": true, "intent": "Wait for two-byte scalar-run grade", "latest": false, "lines": null, "max_age_hours": null, "max_wait_seconds": 120, "notify": null, "return_on_progress": false, "session_only": true, "status_filter": null, "tail_lines": 100, "task_id": "9178491lfp", "task_ids": null, "wait_mode": "any", "wake": null}

Background task was already finished. Task: 9178491lfp Name: Grade two-byte scalar-run op Tool: bash Status: completed Session: session_cactus_1784428616358_ad1e0a14fe6acb8b Started: 2026-07-19T02:41:57.849808985+00:00 Completed: 2026-07-19T02:42:01.160532313+00:00 Duration: 3.31s Exit code: 0 Notify: true Wake: true Recent events: - Completed · 2026-07-19T02:42:01.160556191+00:00 Output preview: ```text build 0.7s verify 2.4s PASS measure 0.1s 31,768,341 instructions (given: 78,181,481) SCORE +1.2992 (2.461x) --- Command finished with exit code: 0 --- ```

{"file_path": "submission/solve.c", "intent": "Consume consecutive surrogate pairs as scalar run", "new_string": " } else if (sx < 0x400u) {\n for (;;) {\n if (p >= end) return INVALID;\n uint32_t lo = *p;\n uint32_t sy = lo - 0xDC00u;\n if (sy >= 0x400u) return INVALID;\n p++;\n uint32_t v = hitab[sx] | lotab[sy];\n store32(q, v);\n q += 4;\n if (p >= end) break;\n c = *p;\n sx = c - 0xD800u;\n if (sx >= 0x400u) break;\n p++;\n }\n } else {", "old_string": " } else if (sx < 0x400u) {\n if (p >= end) return INVALID;\n uint32_t lo = *p;\n uint32_t sy = lo - 0xDC00u;\n if (sy >= 0x400u) return INVALID;\n p++;\n uint32_t v = hitab[sx] | lotab[sy];\n store32(q, v);\n q += 4;\n } else {", "replace_all": false}

Edited submission/solve.c: replaced 1 occurrence(s) 8573- if (p >= end) return INVALID; 8574- uint32_t lo = *p; 8575- uint32_t sy = lo - 0xDC00u; 8576- if (sy >= 0x400u) return INVALID; 8577- p++; 8578- uint32_t v = hitab[sx] | lotab[sy]; 8579- store32(q, v); 8580- q += 4; 8573+ for (;;) { 8574+ if (p >= end) return INVALID; 8575+ uint32_t lo = *p; 8576+ uint32_t sy = lo - 0xDC00u; 8577+ if (sy >= 0x400u) return INVALID; 8578+ p++; 8579+ uint32_t v = hitab[sx] | lotab[sy]; 8580+ store32(q, v); 8581+ q += 4; 8582+ if (p >= end) break; 8583+ c = *p; 8584+ sx = c - 0xD800u; 8585+ if (sx >= 0x400u) break; 8586+ p++; 8587+ } Context after edit (lines 8569-8591): 8569│ p++; 8570│ } 8571│ } 8572│ } else if (sx < 0x400u) { 8573│ for (;;) { 8574│ if (p >= end) return INVALID; 8575│ uint32_t lo = *p; 8576│ uint32_t sy = lo - 0xDC00u; 8577│ if (sy >= 0x400u) return INVALID; 8578│ p++; 8579│ uint32_t v = hitab[sx] | lotab[sy]; 8580│ store32(q, v); 8581│ q += 4; 8582│ if (p >= end) break; 8583│ c = *p; 8584│ sx = c - 0xD800u; 8585│ if (sx >= 0x400u) break; 8586│ p++; 8587│ } 8588│ } else { 8589│ return INVALID; 8590│ } 8591│ }

{"command": "./grade --seed 1", "intent": "Grade surrogate-pair run optimization", "notify": true, "run_in_background": true, "timeout": 1200000, "wake": true}

Command started in background. Task ID: 931000tjw0 Name: Grade surrogate-pair run opt Output file: /tmp/jcode-bg-tasks/931000tjw0.output Status file: /tmp/jcode-bg-tasks/931000tjw0.status.json The agent will be woken when the task completes. To wait for completion/checkpoints: use the `bg` tool with action="wait" and task_id="931000tjw0" To check progress immediately: use the `bg` tool with action="status" and task_id="931000tjw0" To see output: use the `read` tool on the output file, or `bg` with action="output"

{"action": "wait", "dry_run": null, "graceful_timeout_ms": null, "include_output_preview": true, "intent": "Wait for surrogate run grade", "latest": false, "lines": null, "max_age_hours": null, "max_wait_seconds": 120, "notify": null, "return_on_progress": false, "session_only": true, "status_filter": null, "tail_lines": 100, "task_id": "931000tjw0", "task_ids": null, "wait_mode": "any", "wake": null}

Background task finished. Task: 931000tjw0 Name: Grade surrogate-pair run opt Tool: bash Status: completed Session: session_cactus_1784428616358_ad1e0a14fe6acb8b Started: 2026-07-19T02:42:11.000480759+00:00 Completed: 2026-07-19T02:42:14.329508016+00:00 Duration: 3.33s Exit code: 0 Notify: true Wake: true Recent events: - Completed · 2026-07-19T02:42:14.329533998+00:00 Output preview: ```text build 0.7s verify 2.4s PASS measure 0.1s 31,027,517 instructions (given: 78,181,481) SCORE +1.3333 (2.520x) --- Command finished with exit code: 0 --- ```

{"file_path": "submission/solve.c", "intent": "Add 32-unit ASCII SIMD loop before 16-unit loop", "new_string": " while ((size_t)(end - p) >= 32) {\n __m128i a = _mm_loadu_si128((const __m128i *)(const void *)p);\n __m128i b = _mm_loadu_si128((const __m128i *)(const void *)(p + 8));\n __m128i c2 = _mm_loadu_si128((const __m128i *)(const void *)(p + 16));\n __m128i d = _mm_loadu_si128((const __m128i *)(const void *)(p + 24));\n __m128i packed0 = _mm_packus_epi16(a, b);\n __m128i packed1 = _mm_packus_epi16(c2, d);\n __m128i m = _mm_or_si128(_mm_or_si128(a, b), _mm_or_si128(c2, d));\n if ((_mm_movemask_epi8(packed0) | _mm_movemask_epi8(packed1) | _mm_movemask_epi8(m)) != 0) break;\n _mm_storeu_si128((__m128i *)(void *)q, packed0);\n _mm_storeu_si128((__m128i *)(void *)(q + 16), packed1);\n p += 32;\n q += 32;\n }\n while ((size_t)(end - p) >= 16) {", "old_string": " while ((size_t)(end - p) >= 16) {", "replace_all": false}

Edited submission/solve.c: replaced 1 occurrence(s) 8497+ while ((size_t)(end - p) >= 32) { 8498+ __m128i a = _mm_loadu_si128((const __m128i *)(const void *)p); 8499+ __m128i b = _mm_loadu_si128((const __m128i *)(const void *)(p + 8)); 8500+ __m128i c2 = _mm_loadu_si128((const __m128i *)(const void *)(p + 16)); 8501+ __m128i d = _mm_loadu_si128((const __m128i *)(const void *)(p + 24)); 8502+ __m128i packed0 = _mm_packus_epi16(a, b); 8503+ __m128i packed1 = _mm_packus_epi16(c2, d); 8504+ __m128i m = _mm_or_si128(_mm_or_si128(a, b), _mm_or_si128(c2, d)); 8505+ if ((_mm_movemask_epi8(packed0) | _mm_movemask_epi8(packed1) | _mm_movemask_epi8(m)) != 0) break; 8506+ _mm_storeu_si128((__m128i *)(void *)q, packed0); 8507+ _mm_storeu_si128((__m128i *)(void *)(q + 16), packed1); 8508+ p += 32; 8509+ q += 32; 8510+ } Context after edit (lines 8494-8514): 8494│ if (c < 0x80) { 8495│ *q++ = (uint8_t)c; 8496│ 8497│ while ((size_t)(end - p) >= 32) { 8498│ __m128i a = _mm_loadu_si128((const __m128i *)(const void *)p); 8499│ __m128i b = _mm_loadu_si128((const __m128i *)(const void *)(p + 8)); 8500│ __m128i c2 = _mm_loadu_si128((const __m128i *)(const void *)(p + 16)); 8501│ __m128i d = _mm_loadu_si128((const __m128i *)(const void *)(p + 24)); 8502│ __m128i packed0 = _mm_packus_epi16(a, b); 8503│ __m128i packed1 = _mm_packus_epi16(c2, d); 8504│ __m128i m = _mm_or_si128(_mm_or_si128(a, b), _mm_or_si128(c2, d)); 8505│ if ((_mm_movemask_epi8(packed0) | _mm_movemask_epi8(packed1) | _mm_movemask_epi8(m)) != 0) break; 8506│ _mm_storeu_si128((__m128i *)(void *)q, packed0); 8507│ _mm_storeu_si128((__m128i *)(void *)(q + 16), packed1); 8508│ p += 32; 8509│ q += 32; 8510│ } 8511│ while ((size_t)(end - p) >= 16) { 8512│ __m128i a = _mm_loadu_si128((const __m128i *)(const void *)p); 8513│ __m128i b = _mm_loadu_si128((const __m128i *)(const void *)(p + 8)); 8514│ __m128i m = _mm_or_si128(a, b);

{"command": "./grade --seed 1", "intent": "Grade 32-unit ASCII loop", "notify": true, "run_in_background": true, "timeout": 1200000, "wake": true}

Command started in background. Task ID: 942180d8l5 Name: Grade 32-unit ASCII loop Output file: /tmp/jcode-bg-tasks/942180d8l5.output Status file: /tmp/jcode-bg-tasks/942180d8l5.status.json The agent will be woken when the task completes. To wait for completion/checkpoints: use the `bg` tool with action="wait" and task_id="942180d8l5" To check progress immediately: use the `bg` tool with action="status" and task_id="942180d8l5" To see output: use the `read` tool on the output file, or `bg` with action="output"

{"action": "wait", "dry_run": null, "graceful_timeout_ms": null, "include_output_preview": true, "intent": "Wait for 32-unit ASCII grade", "latest": false, "lines": null, "max_age_hours": null, "max_wait_seconds": 120, "notify": null, "return_on_progress": false, "session_only": true, "status_filter": null, "tail_lines": 100, "task_id": "942180d8l5", "task_ids": null, "wait_mode": "any", "wake": null}

Background task finished. Task: 942180d8l5 Name: Grade 32-unit ASCII loop Tool: bash Status: completed Session: session_cactus_1784428616358_ad1e0a14fe6acb8b Started: 2026-07-19T02:42:22.180714524+00:00 Completed: 2026-07-19T02:42:25.584634821+00:00 Duration: 3.40s Exit code: 0 Notify: true Wake: true Recent events: - Completed · 2026-07-19T02:42:25.584651584+00:00 Output preview: ```text build 0.7s verify 2.4s PASS measure 0.1s 33,438,566 instructions (given: 78,181,481) SCORE +1.2253 (2.338x) --- Command finished with exit code: 0 --- ```

{"file_path": "submission/solve.c", "intent": "Revert regressing 32-unit ASCII loop", "new_string": "", "old_string": " while ((size_t)(end - p) >= 32) {\n __m128i a = _mm_loadu_si128((const __m128i *)(const void *)p);\n __m128i b = _mm_loadu_si128((const __m128i *)(const void *)(p + 8));\n __m128i c2 = _mm_loadu_si128((const __m128i *)(const void *)(p + 16));\n __m128i d = _mm_loadu_si128((const __m128i *)(const void *)(p + 24));\n __m128i packed0 = _mm_packus_epi16(a, b);\n __m128i packed1 = _mm_packus_epi16(c2, d);\n __m128i m = _mm_or_si128(_mm_or_si128(a, b), _mm_or_si128(c2, d));\n if ((_mm_movemask_epi8(packed0) | _mm_movemask_epi8(packed1) | _mm_movemask_epi8(m)) != 0) break;\n _mm_storeu_si128((__m128i *)(void *)q, packed0);\n _mm_storeu_si128((__m128i *)(void *)(q + 16), packed1);\n p += 32;\n q += 32;\n }\n", "replace_all": false}

Edited submission/solve.c: replaced 1 occurrence(s) 8497- while ((size_t)(end - p) >= 32) { 8498- __m128i a = _mm_loadu_si128((const __m128i *)(const void *)p); 8499- __m128i b = _mm_loadu_si128((const __m128i *)(const void *)(p + 8)); 8500- __m128i c2 = _mm_loadu_si128((const __m128i *)(const void *)(p + 16)); 8501- __m128i d = _mm_loadu_si128((const __m128i *)(const void *)(p + 24)); 8502- __m128i packed0 = _mm_packus_epi16(a, b); 8503- __m128i packed1 = _mm_packus_epi16(c2, d); 8504- __m128i m = _mm_or_si128(_mm_or_si128(a, b), _mm_or_si128(c2, d)); 8505- if ((_mm_movemask_epi8(packed0) | _mm_movemask_epi8(packed1) | _mm_movemask_epi8(m)) != 0) break; 8506- _mm_storeu_si128((__m128i *)(void *)q, packed0); 8507- _mm_storeu_si128((__m128i *)(void *)(q + 16), packed1); 8508- p += 32; 8509- q += 32; 8510- } Context after edit (lines 8494-8500): 8494│ if (c < 0x80) { 8495│ *q++ = (uint8_t)c; 8496│ 8497│ while ((size_t)(end - p) >= 16) { 8498│ __m128i a = _mm_loadu_si128((const __m128i *)(const void *)p); 8499│ __m128i b = _mm_loadu_si128((const __m128i *)(const void *)(p + 8)); 8500│ __m128i m = _mm_or_si128(a, b);

{"command": "cp submission/solve.c \"$JCODE_SCRATCH_DIR/solve_before_pairtab.c\"\npython3 - <<'PY'\nfrom pathlib import Path\np=Path('submission/solve.c')\ns=p.read_text()\narr=[]\nfor x in range(1024):\n for y in range(1024):\n b0=0xF0 | ((x + 0x40) >> 8)\n b1=0x80 | ((0x10 + (x >> 2)) & 0x3F)\n b2=0x80 | (((x & 3) << 4) | (y >> 6))\n b3=0x80 | (y & 0x3f)\n arr.append(b0 | (b1<<8) | (b2<<16) | (b3<<24))\nlines=['static const uint32_t pairtab[1048576] = {']\nfor i in range(0,len(arr),8):\n lines.append(' '+', '.join(f'0x{x:08x}u' for x in arr[i:i+8])+',')\nlines.append('};')\ninsert='\\n'.join(lines)+'\\n\\n'\nmarker='static const uint8_t shuf3_a0[16]'\nif 'static const uint32_t pairtab[1048576]' not in s:\n s=s.replace(marker, insert+marker, 1)\ns=s.replace('uint32_t v = hitab[sx] | lotab[sy];','uint32_t v = pairtab[(sx << 10) | sy];')\np.write_text(s)\nPY\nwc -c submission/solve.c", "intent": "Generate full surrogate-pair table variant", "notify": false, "run_in_background": false, "timeout": 120000, "wake": false}

15073944 submission/solve.c --- Command finished with exit code: 0 ---

{"command": "./grade --seed 1", "intent": "Grade full surrogate-pair table variant", "notify": true, "run_in_background": true, "timeout": 1200000, "wake": true}

Command started in background. Task ID: 969278z1tu Name: Grade full surrogate-pair ta Output file: /tmp/jcode-bg-tasks/969278z1tu.output Status file: /tmp/jcode-bg-tasks/969278z1tu.status.json The agent will be woken when the task completes. To wait for completion/checkpoints: use the `bg` tool with action="wait" and task_id="969278z1tu" To check progress immediately: use the `bg` tool with action="status" and task_id="969278z1tu" To see output: use the `read` tool on the output file, or `bg` with action="output"

{"action": "wait", "dry_run": null, "graceful_timeout_ms": null, "include_output_preview": true, "intent": "Wait for full pair-table grade", "latest": false, "lines": null, "max_age_hours": null, "max_wait_seconds": 120, "notify": null, "return_on_progress": false, "session_only": true, "status_filter": null, "tail_lines": 100, "task_id": "969278z1tu", "task_ids": null, "wait_mode": "any", "wake": null}

Background task finished. Task: 969278z1tu Name: Grade full surrogate-pair ta Tool: bash Status: completed Session: session_cactus_1784428616358_ad1e0a14fe6acb8b Started: 2026-07-19T02:42:49.278808222+00:00 Completed: 2026-07-19T02:42:55.954317828+00:00 Duration: 6.67s Exit code: 0 Notify: true Wake: true Recent events: - Completed · 2026-07-19T02:42:55.954352503+00:00 Output preview: ```text build 4.0s verify 2.4s PASS measure 0.1s 31,307,095 instructions (given: 78,181,481) SCORE +1.3203 (2.497x) --- Command finished with exit code: 0 --- ```

{"command": "cp \"$JCODE_SCRATCH_DIR/solve_before_pairtab.c\" submission/solve.c\nwc -c submission/solve.c", "intent": "Revert regressing full pair-table variant", "notify": false, "run_in_background": false, "timeout": 120000, "wake": false}

918118 submission/solve.c --- Command finished with exit code: 0 ---

{"file_path": "submission/solve.c", "intent": "Add restrict qualifiers to function parameters", "new_string": "size_t utf16_to_utf8(const uint16_t * restrict in, size_t n, uint8_t * restrict out) {", "old_string": "size_t utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out) {", "replace_all": false}

Edited submission/solve.c: replaced 1 occurrence(s) 8477- size_t utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out) { 8477+ size_t utf16_to_utf8(const uint16_t * restrict in, size_t n, uint8_t * restrict out) { Context after edit (lines 8474-8480): 8474│ static const uint8_t shuf3_c1[16] __attribute__((aligned(16))) = {0x80,5,0x80,0x80,6,0x80,0x80,7,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80}; 8475│ 8476│ __attribute__((target("ssse3"))) 8477│ size_t utf16_to_utf8(const uint16_t * restrict in, size_t n, uint8_t * restrict out) { 8478│ const uint16_t *p = in; 8479│ const uint16_t *end = in + n; 8480│ uint8_t *q = out;

{"command": "./grade --seed 1", "intent": "Grade restrict-qualified version", "notify": true, "run_in_background": true, "timeout": 1200000, "wake": true}

Command started in background. Task ID: 985995ifkw Name: Grade restrict-qualified ver Output file: /tmp/jcode-bg-tasks/985995ifkw.output Status file: /tmp/jcode-bg-tasks/985995ifkw.status.json The agent will be woken when the task completes. To wait for completion/checkpoints: use the `bg` tool with action="wait" and task_id="985995ifkw" To check progress immediately: use the `bg` tool with action="status" and task_id="985995ifkw" To see output: use the `read` tool on the output file, or `bg` with action="output"

{"action": "wait", "dry_run": null, "graceful_timeout_ms": null, "include_output_preview": true, "intent": "Wait for restrict grade", "latest": false, "lines": null, "max_age_hours": null, "max_wait_seconds": 120, "notify": null, "return_on_progress": false, "session_only": true, "status_filter": null, "tail_lines": 100, "task_id": "985995ifkw", "task_ids": null, "wait_mode": "any", "wake": null}

Background task finished. Task: 985995ifkw Name: Grade restrict-qualified ver Tool: bash Status: completed Session: session_cactus_1784428616358_ad1e0a14fe6acb8b Started: 2026-07-19T02:43:05.995696759+00:00 Completed: 2026-07-19T02:43:09.381723353+00:00 Duration: 3.39s Exit code: 0 Notify: true Wake: true Recent events: - Completed · 2026-07-19T02:43:09.381736462+00:00 Output preview: ```text build 0.7s verify 2.5s PASS measure 0.1s 31,027,517 instructions (given: 78,181,481) SCORE +1.3333 (2.520x) --- Command finished with exit code: 0 --- ```

{"command": "./grade --seed 2", "intent": "Cross-check optimized solution on a second corpus seed", "notify": true, "run_in_background": true, "timeout": 1200000, "wake": true}

Command started in background. Task ID: 992489mhsv Name: Cross-check optimized soluti Output file: /tmp/jcode-bg-tasks/992489mhsv.output Status file: /tmp/jcode-bg-tasks/992489mhsv.status.json The agent will be woken when the task completes. To wait for completion/checkpoints: use the `bg` tool with action="wait" and task_id="992489mhsv" To check progress immediately: use the `bg` tool with action="status" and task_id="992489mhsv" To see output: use the `read` tool on the output file, or `bg` with action="output"

{"action": "wait", "dry_run": null, "graceful_timeout_ms": null, "include_output_preview": true, "intent": "Wait for second seed grade", "latest": false, "lines": null, "max_age_hours": null, "max_wait_seconds": 120, "notify": null, "return_on_progress": false, "session_only": true, "status_filter": null, "tail_lines": 100, "task_id": "992489mhsv", "task_ids": null, "wait_mode": "any", "wake": null}

Background task finished. Task: 992489mhsv Name: Cross-check optimized soluti Tool: bash Status: completed Session: session_cactus_1784428616358_ad1e0a14fe6acb8b Started: 2026-07-19T02:43:12.489662945+00:00 Completed: 2026-07-19T02:43:16.457288205+00:00 Duration: 3.97s Exit code: 0 Notify: true Wake: true Recent events: - Completed · 2026-07-19T02:43:16.457307430+00:00 Output preview: ```text build 0.7s verify 2.5s PASS measure 0.7s 30,807,287 instructions (given: 77,756,473) SCORE +1.3357 (2.524x) --- Command finished with exit code: 0 --- ```

{"command": "git status --short && git rev-parse --show-toplevel 2>/dev/null || true", "intent": "Check repository status before final validation/commit", "notify": false, "run_in_background": false, "timeout": 120000, "wake": false}

fatal: not a git repository (or any of the parent directories): .git --- Command finished with exit code: 0 ---

{"command": "./grade", "intent": "Run final grade on optimized submission", "notify": true, "run_in_background": true, "timeout": 1200000, "wake": true}

Command started in background. Task ID: 0012548grh Name: Run final grade on optimized Output file: /tmp/jcode-bg-tasks/0012548grh.output Status file: /tmp/jcode-bg-tasks/0012548grh.status.json The agent will be woken when the task completes. To wait for completion/checkpoints: use the `bg` tool with action="wait" and task_id="0012548grh" To check progress immediately: use the `bg` tool with action="status" and task_id="0012548grh" To see output: use the `read` tool on the output file, or `bg` with action="output"

{"action": "wait", "dry_run": null, "graceful_timeout_ms": null, "include_output_preview": true, "intent": "Wait for final grade", "latest": false, "lines": null, "max_age_hours": null, "max_wait_seconds": 120, "notify": null, "return_on_progress": false, "session_only": true, "status_filter": null, "tail_lines": 100, "task_id": "0012548grh", "task_ids": null, "wait_mode": "any", "wake": null}

Background task finished. Task: 0012548grh Name: Run final grade on optimized Tool: bash Status: completed Session: session_cactus_1784428616358_ad1e0a14fe6acb8b Started: 2026-07-19T02:43:21.254506655+00:00 Completed: 2026-07-19T02:43:25.199880388+00:00 Duration: 3.94s Exit code: 0 Notify: true Wake: true Recent events: - Completed · 2026-07-19T02:43:25.199903783+00:00 Output preview: ```text build 0.7s verify 2.5s PASS measure 0.7s 30,886,461 instructions (given: 77,865,996) SCORE +1.3340 (2.521x) --- Command finished with exit code: 0 --- ```

{"goals": [{"end_to_end_ownership": 96, "feedback_loop": "Ran ./grade after each candidate optimization, compared deterministic seed-1 scores, cross-checked seed 2, and finalized with an unseeded ./grade pass.", "group": "utf16-transcode", "hill_climbability": 100, "objective": "Maximize verified score improvement for submission/solve.c, measured as the latest ./grade score after correctness passes, with previous best score tracked across iterations.", "user_intention": "Achieve the highest benchmark score possible for utf16-transcode.", "user_intention_alignment": 100}], "intent": "Mark benchmark optimization complete", "todos": [{"completion_confidence": 100, "confidence": 95, "content": "Read spec.md and baseline implementation", "group": "utf16-transcode", "id": "read-spec", "priority": "high", "status": "completed"}, {"completion_confidence": 100, "confidence": 90, "content": "Run baseline grade to record starting score and latest scores.jsonl entry", "group": "utf16-transcode", "id": "baseline-grade", "priority": "high", "status": "completed"}, {"completion_confidence": 94, "confidence": 85, "content": "Implement candidate optimizations in submission/solve.c and retain only correctness-passing score improvements", "group": "utf16-transcode", "id": "optimize", "priority": "high", "status": "completed"}, {"completion_confidence": 100, "confidence": 90, "content": "Run final ./grade, record latest verified score, and report it", "group": "utf16-transcode", "id": "final-grade", "priority": "high", "status": "completed"}]}

[ { "content": "Read spec.md and baseline implementation", "status": "completed", "priority": "high", "id": "read-spec", "group": "utf16-transcode", "confidence": 95, "completion_confidence": 100, "confidence_history": [ 95, 100 ] }, { "content": "Run baseline grade to record starting score and latest scores.jsonl entry", "status": "completed", "priority": "high", "id": "baseline-grade", "group": "utf16-transcode", "confidence": 90, "completion_confidence": 100, "confidence_history": [ 90, 100 ] }, { "content": "Implement candidate optimizations in submission/solve.c and retain only correctness-passing score improvements", "status": "completed", "priority": "high", "id": "optimize", "group": "utf16-transcode", "confidence": 85, "completion_confidence": 94, "confidence_history": [ 85, 94 ] }, { "content": "Run final ./grade, record latest verified score, and report it", "status": "completed", "priority": "high", "id": "final-grade", "group": "utf16-transcode", "confidence": 90, "completion_confidence": 100, "confidence_history": [ 90, 100 ] } ] Goals: [ { "group": "utf16-transcode", "user_intention": "Achieve the highest benchmark score possible for utf16-transcode.", "user_intention_alignment": 100, "hill_climbability": 100, "objective": "Maximize verified score improvement for submission/solve.c, measured as the latest ./grade score after correctness passes, with previous best score tracked across iterations.", "feedback_loop": "Ran ./grade after each candidate optimization, compared deterministic seed-1 scores, cross-checked seed 2, and finalized with an unseeded ./grade pass.", "end_to_end_ownership": 96 } ]