# Phase 67: Citation Traversal And Source-Family Reuse - Context

**Gathered:** 2026-04-11
**Status:** Implemented and verified
**Mode:** Brownfield continuation after closing Phase `66`

<domain>
## Phase Boundary

Turn the compiled source catalog into bounded reusable navigation surfaces:

- citation traversal for one canonical source
- source-family reuse reports for one source type
- durable service/CLI entrypoints for both

This phase is about queryable source reuse.
It is not yet about fidelity-aware runtime read surfaces.

</domain>

<decisions>
## Implementation Decisions

### Locked decisions

- Reuse the compiled source catalog as the input layer instead of recomputing
  source grouping in separate command handlers.
- Keep traversal bounded to one-hop incoming and outgoing catalog links.
- Materialize traversal and family reports under
  `source-layer/compiled/citation_traversals/` and
  `source-layer/compiled/source_families/`.

### the agent's Discretion

- Exact markdown layout for traversal and family reports.
- Which summary counters to foreground in the first reusable navigation slice.

</decisions>

<canonical_refs>
## Canonical References

- `research/knowledge-hub/knowledge_hub/source_catalog.py`
- `research/knowledge-hub/knowledge_hub/cli_source_catalog_handler.py`
- `research/knowledge-hub/knowledge_hub/aitp_service.py`
- `research/knowledge-hub/tests/test_source_catalog.py`
- `research/knowledge-hub/tests/test_aitp_service.py`
- `research/knowledge-hub/tests/test_aitp_cli.py`
- `research/knowledge-hub/tests/test_aitp_cli_e2e.py`

</canonical_refs>

<code_context>
## Existing Code Insights

- Phase `66` already compiled cross-topic source identity into
  `source_catalog.json|md`, so the missing step was bounded navigation over that
  compiled identity graph.
- The cleanest production boundary was to extend the existing source-catalog
  compiler module plus the extracted source-catalog CLI handler.
- The new service wrappers had to remain thin because `aitp_service.py` still
  sits on a maintainability watch budget.

</code_context>

<specifics>
## Specific Ideas

- Add `trace-source-citations --canonical-source-id ...`
- Add `compile-source-family --source-type ...`
- Materialize one-hop incoming/outgoing citation traversal and family reuse
  summaries as JSON and markdown artifacts

</specifics>

<deferred>
## Deferred Ideas

- fidelity ranking
- runtime read-path integration for evidence weight
- milestone-close acceptance packaging

</deferred>

---

*Phase: 67-citation-traversal-and-source-family-reuse*
*Context captured on 2026-04-11 after Phase 67 implementation and verification*
