Handle zero-token source rows in code trace audit

runs/frontier-code-trace-v0/README.md

@@ -34,6 +34,9 @@ selected.selected_window_stats.max_model_len_coverage[推荐值].coverage = 1.0
 ```
 
 旧记录预计 source block size 为 512、推荐 max model len 为 131072，但禁止把这两个值写死为实验事实。
+审计会单独记录并排除 `input_length<=0` 或 `output_length<=0` 的 source
+行；这些行只有在 raw trace 同样显示 zero usage/empty response 时才按
+“未发生模型执行”处理，不能无记录过滤。
 
 ## 2. 物化稳定窗口
 

runs/frontier-code-trace-v0/audit_code_trace.py

@@ -131,6 +131,9 @@ def choose_window(
 
 def scan_source(path: Path, args: argparse.Namespace) -> dict[str, Any]:
     rows = 0
+    source_rows = 0
+    invalid_zero_token_rows = 0
+    invalid_zero_token_examples: list[dict[str, Any]] = []
     first_timestamp = None
     last_timestamp = None
     previous_timestamp = None
@@ -145,6 +148,7 @@ def scan_source(path: Path, args: argparse.Namespace) -> dict[str, Any]:
     sampling_rows = 0
     schema_keys: Counter[str] = Counter()
     for line_number, row in iter_jsonl(path):
+        source_rows += 1
         missing = [
             key
             for key in ("timestamp", "input_length", "output_length")
@@ -153,6 +157,22 @@ def scan_source(path: Path, args: argparse.Namespace) -> dict[str, Any]:
         if missing:
             raise ValueError(f"{path}:{line_number}: missing required fields {missing}")
         timestamp = float(row["timestamp"])
+        input_tokens = int(row["input_length"])
+        output_tokens = int(row["output_length"])
+        schema_keys.update(row.keys())
+        if input_tokens <= 0 or output_tokens <= 0:
+            invalid_zero_token_rows += 1
+            if len(invalid_zero_token_examples) < 20:
+                invalid_zero_token_examples.append(
+                    {
+                        "line_number": line_number,
+                        "chat_id": row.get("chat_id"),
+                        "timestamp": timestamp,
+                        "input_length": input_tokens,
+                        "output_length": output_tokens,
+                    }
+                )
+            continue
         if first_timestamp is None:
             first_timestamp = timestamp
         if previous_timestamp is not None and timestamp < previous_timestamp:
@@ -169,10 +189,6 @@ def scan_source(path: Path, args: argparse.Namespace) -> dict[str, Any]:
                 max_gaps.get(previous_bin, 0.0),
                 timestamp - previous_timestamp,
             )
-        input_tokens = int(row["input_length"])
-        output_tokens = max(1, int(row["output_length"]))
-        if input_tokens <= 0:
-            raise ValueError(f"{path}:{line_number}: input_length must be positive")
         input_lengths.append(input_tokens)
         output_lengths.append(output_tokens)
         total_lengths.append(input_tokens + output_tokens)
@@ -186,7 +202,6 @@ def scan_source(path: Path, args: argparse.Namespace) -> dict[str, Any]:
             isinstance(row.get("prompt"), (str, list)) and bool(row.get("prompt"))
         )
         sampling_rows += int("sampling_u" in row)
-        schema_keys.update(row.keys())
         rows += 1
         previous_timestamp = timestamp
         last_timestamp = timestamp
@@ -205,6 +220,10 @@ def scan_source(path: Path, args: argparse.Namespace) -> dict[str, Any]:
     return {
         "source": str(path.resolve()),
         "rows": rows,
+        "source_rows": source_rows,
+        "invalid_zero_token_rows": invalid_zero_token_rows,
+        "invalid_zero_token_fraction": invalid_zero_token_rows / source_rows,
+        "invalid_zero_token_examples": invalid_zero_token_examples,
         "first_timestamp": first_timestamp,
         "last_timestamp": last_timestamp,
         "span_s": last_timestamp - first_timestamp,
@@ -253,7 +272,9 @@ def scan_window(source: Path, window: dict[str, Any]) -> dict[str, Any]:
         if timestamp >= end:
             break
         input_tokens = int(row["input_length"])
-        output_tokens = max(1, int(row["output_length"]))
+        output_tokens = int(row["output_length"])
+        if input_tokens <= 0 or output_tokens <= 0:
+            continue
         inputs.append(input_tokens)
         outputs.append(output_tokens)
         totals.append(input_tokens + output_tokens)

runs/frontier-code-trace-v0/experiment-card.md

@@ -58,6 +58,7 @@ strict decode-only 必须同时具备：
 
 - timestamp 单调，存在 60–75min 连续稳定窗口；
 - `timestamp/input_length/output_length` 全行存在；
+- `input_length<=0` 或 `output_length<=0` 的行不进入 replay，但必须计数并保留样例。已抽查的两条 0→0 行在 raw trace 中同时满足 `usage.total_tokens=0`、`response_message={}`，属于未发生模型执行的 source request，不是 full-cache decode；
 - `hash_ids` 数量与某个 source block size 在全行严格满足
   `ceil(ISL/source_block_size)`；预计值 512，但以审计结果为准；
 - 记录 ISL/OSL/ISL+OSL 的 p50/p90/p95/p99/max、gap、request rate、prompt/sampling 字段覆盖。

runs/frontier-code-trace-v0/prepare_code_window.py

@@ -63,6 +63,8 @@ def main() -> None:
                 continue
             if timestamp >= end:
                 break
+            if int(row["input_length"]) <= 0 or int(row["output_length"]) <= 0:
+                continue
             chat = row.get("chat_id", source_index)
             parent = row.get("parent_chat_id")
             has_parent = parent not in (None, "", -1, "-1")

runs/frontier-code-trace-v0/test_code_trace_preflight.py

@@ -20,6 +20,21 @@ class CodeTracePreflightTest(unittest.TestCase):
             source = root / "051315-051317.jsonl"
             with source.open("w") as stream:
                 for index in range(4501):
+                    if index == 100:
+                        stream.write(
+                            json.dumps(
+                                {
+                                    "chat_id": index,
+                                    "parent_chat_id": -1,
+                                    "timestamp": float(index),
+                                    "input_length": 0,
+                                    "output_length": 0,
+                                    "hash_ids": [],
+                                }
+                            )
+                            + "\n"
+                        )
+                        continue
                     input_tokens = 513 if index % 2 else 512
                     stream.write(
                         json.dumps(
@@ -53,6 +68,7 @@ class CodeTracePreflightTest(unittest.TestCase):
             self.assertEqual(
                 payload["selected"]["hash_contract"]["exact_source_block_size"], 512
             )
+            self.assertEqual(payload["selected"]["invalid_zero_token_rows"], 1)
             self.assertEqual(payload["max_model_len_recommendation"], 40960)
             output = root / "window"
             subprocess.run(
@@ -74,6 +90,7 @@ class CodeTracePreflightTest(unittest.TestCase):
         self.assertEqual(manifest["requests"], len(rows))
         self.assertGreaterEqual(manifest["duration_s"], 3600)
         self.assertEqual(rows[0]["sampling_u"], rows[1]["sampling_u"])
+        self.assertNotIn(100, {row["source_index"] for row in rows})
 
 
 if __name__ == "__main__":