# Evidence Trace Hardening Decisions

## Clarify

- Entry summary: harden the MVP evidence contract before building the P1-B evaluation harness.
- Slug: `evidence-trace-hardening`
- Devflow scale: standard-light

## Context

- `ISS-003` raised verifier traceability and failure-path concerns.
- Current code inspection shows `QueryLogsTools` and `QueryMetricsTools` already use `ToolInvocationRecorder`, while `LookupKnowledgeTool` still persists rows through a local helper.
- `ChatService` already contains fallback behavior for missing/invalid `verifier_output`, but coverage is narrow.

## Key Decisions

- Decision: Treat this as a contract-hardening change, not a new feature change.
  - Reason: The project already has the necessary runtime pieces; the gap is semantic consistency and testability.

- Decision: Keep the scope before P1-B.
  - Reason: The evaluation harness will rely on stable evidence semantics, so this contract slice should land first.

- Decision: Preserve schema and API stability.
  - Reason: The interview value here is engineering rigor, not more surface area.