# lens-instrumentation

## AUDIT (2026-01-31)

**Pattern:** Lens `resolve()` methods missing `#[instrument]` tracing spans
**Found:** 3 instances in 3 files

| File | Method | Has `#[instrument]` |
|------|--------|---------------------|
| `recency.rs:24` | `RecencyLens::resolve()` | NO |
| `consensus.rs:34` | `ConsensusLens::resolve()` | NO |
| `confidence.rs:46` | `ConfidenceLens::resolve()` | NO |
| `vote_aware_consensus.rs:120` | `VoteAwareConsensusLens::resolve_async()` | YES (already) |
| `trust_aware_authority.rs:90` | `TrustAwareAuthorityLens::resolve_async()` | YES (already) |

*Note: `authority.rs` was renamed to `confidence.rs` and `AuthorityLens` to `ConfidenceLens` in Task 2.2.*

The async lenses were instrumented when created. The synchronous lenses predate the tracing-coverage remediation.

## FIX (2026-01-31)

Added `#[instrument]` to all 3 synchronous lens `resolve()` methods:

| File | Change |
|------|--------|
| `recency.rs` | Added `use tracing::instrument;` + `#[instrument(skip(self, candidates), fields(candidates_count = candidates.len(), lens = "Recency"))]` |
| `consensus.rs` | Added `use tracing::instrument;` + `#[instrument(skip(self, candidates), fields(candidates_count = candidates.len(), lens = "Consensus"))]` |
| `confidence.rs` | Added `use tracing::instrument;` + `#[instrument(skip(self, candidates), fields(candidates_count = candidates.len(), lens = "Confidence"))]` |

*Note: File was originally `authority.rs` (renamed to `confidence.rs` in Task 2.2).*

Build verified: `cargo build --workspace` + `cargo clippy --workspace -- -D warnings` both pass.

## VERIFY (2026-01-31)

Grep confirmed 5/5 lens implementations instrumented, 0 remaining gaps:
- RecencyLens::resolve() ✅
- ConsensusLens::resolve() ✅
- ConfidenceLens::resolve() ✅ (renamed from AuthorityLens in Task 2.2)
- VoteAwareConsensusLens::resolve_async() ✅ (already)
- TrustAwareAuthorityLens::resolve_async() ✅ (already)

## ENFORCE (2026-01-31)

Updated CLAUDE.md critical rule:
- Before: "Use `#[instrument]` on public methods in WAL, storage, and ingestion code."
- After: "Use `#[instrument]` on public methods in WAL, storage, ingestion, and lens code. Include meaningful fields (key_len, payload_len, offset, candidates_count, lens)."

## DOCUMENT (2026-01-31)

Updated `.claude/skills/stemedb-lens/SKILL.md`:
- Updated trait signatures to match current code (Lens + AsyncLens)
- Added "Current Implementations" table with all 5 lenses
- Added "Tracing Pattern (Required)" section with example
- Added `#[instrument]` to the "Do" checklist
- Updated strategies to reflect actual implementation details