Define exact full-score Pass Rate and document payload integrity

README.md

@@ -63,6 +63,41 @@ Verify a downloaded solve package with:
 python tools/verify_dataset.py
 ```
 
+## Metrics
+
+Official Pass Rate uses **exact full credit**: a task passes only when
+`evaluation_complete == 1` and `task_score == 1.0`. Native per-task
+thresholds and the raw verifier's `passed` flag do not determine this metric.
+There is no rounding or tolerance: `0.999` is not a pass.
+
+- **Pass Rate (%)** = 100 × number of completed full-score tasks / 97.
+- **Score (0–100)** = 100 × sum of valid, completed `task_score` values / 97.
+- Partial credit remains the native rubric score normalized to [0, 1].
+  Missing tasks, invalid scores, and incomplete evaluations contribute zero
+  to the fixed denominator and must be reported separately; incomplete runs
+  are not final benchmark results.
+- Use one predeclared attempt per task. A subset may use its predeclared task
+  count as denominator, but must be labeled as a subset, not the 97-task result.
+
+The runtime's `summary.json` records `metric_definition: exact-full-score`;
+its `passed` column follows this rule and `native_passed` preserves the raw
+verifier flag for diagnosis. Archived verifier outputs are unchanged. Historical
+results using native thresholds or score tolerances must be recomputed from
+raw scores before comparison. See the
+[scoring guide](https://github.com/ApodexAI/FrontierAgent/blob/main/benchmarks/frontierchallenge/docs/scoring.md)
+and [runtime update](https://github.com/ApodexAI/FrontierAgent/pull/30).
+
+**Runtime rollout:** the runtime update is pending. Before reporting results,
+check that your summary records `metric_definition: exact-full-score`;
+older runtimes and Harbor's raw `passed` aggregate use the legacy rule.
+
+## Integrity
+
+The root `README.md` is a mutable dataset card and is intentionally outside
+`checksums.sha256`. Task files (including task-level READMEs), manifests,
+registries, and verification tools remain checksummed. Payload changes require
+regenerating their checksum entries; editing this card does not.
+
 ## Citation
 
 ```bibtex