# ADR-0004 — Citation recovery boundary

- **Status:** accepted
- **Date:** 2026-07-09
- **Workplan:** ESRC-WP-0004 (T01)

## Context

`evidence-source` owns ingestion and representation generation. Citation
recovery spans stale-selector detection, local quote search, external source
discovery, and human confirmation — but selector resolution algorithms live in
`evidence-anchor`, and the `CitationRecoveryAttempt` type vocabulary lives in
`citation-engine`.

## Decision

### Owned by `evidence-source`

| Capability | Module | Notes |
| ---------- | ------ | ----- |
| Re-ingest + re-fingerprint | `src/recovery/re-ingest.ts` | Compare prior vs. fresh `Document.fingerprint`; flag `requiresReanchor` |
| Local canonical quote search | `src/recovery/local-search.ts` | Search `DocumentRepresentation.canonicalText` |
| Recovery attempt scaffold | `src/recovery/attempt.ts` | Local record using SharedContracts state vocabulary |
| Discovery hook interface | `src/recovery/discovery.ts` | Pluggable providers; **no network in core** |

### Owned elsewhere

| Capability | Owner |
| ---------- | ----- |
| Stale selector detection / resolution order | `evidence-anchor` |
| `CitationRecoveryAttempt` canonical type | `citation-engine` (future) |
| Human confirmation UX | `citation-work` / umbrella |
| External HTTP/API lookup implementations | Deployment-specific providers registered on the hook |

### Recovery flow

```text
CitationClue
  → createRecoveryAttempt (evidence-source)
  → local library search via searchCanonicalQuote (evidence-source)
  → optional SourceDiscoveryHook providers (registered by host)
  → reIngestAndCompare when fresh bytes arrive (evidence-source)
  → anchor layer re-resolves selectors when requiresReanchor is true
```

`evidence-source` **does not** decide whether a selector is stale. It supplies
primitives the anchor layer calls after it detects mismatch.

## Consequences

- No network coupling in the recovery core.
- Host apps register discovery providers explicitly (local-first default).
- Recovery state enum mirrors `wiki/SharedContracts.md` §2.6 locally until the
  engine exports a shared `CitationRecoveryAttempt` type.