# Requirements: v1.69 L0 Source Discovery Via DeepXiv MCP Integration

## Milestone Goal

Close the pre-registration discovery gap in `L0` so source registration can
start from a natural-language query and candidate evaluation path instead of
assuming the exact `arxiv_id` is already known.

## Completed Requirements

### Search And Discovery Contract

- [x] `REQ-DISCOVERY-01`: the repository exposes one search-first discovery
  path before `L0` registration, with DeepXiv as the primary MCP-backed search
  provider.
- [x] `REQ-DISCOVERY-02`: search results expose enough metadata for bounded
  candidate evaluation before registration, including title, abstract, source
  identifiers, and relevance evidence.

### Registration Bridge

- [x] `REQ-DISCOVERY-03`: one thin adapter bridges discovery results into the
  existing source-registration path without embedding search inside the `L0`
  core protocol.
- [x] `REQ-DISCOVERY-04`: the design keeps search-tool fallbacks explicit so
  discovery still works if DeepXiv is unavailable.

### Verification

- [x] `REQ-VERIFY-01`: the milestone closes with one bounded discovery-to-
  registration acceptance path plus targeted regression coverage for the new
  search bridge.

## Requirement Outcomes

- `REQ-DISCOVERY-01`: validated through the new
  `source-layer/scripts/discover_and_register.py` entrypoint and provider
  chain.
- `REQ-DISCOVERY-02`: validated through durable
  `search_results.json` and `candidate_evaluation.json` receipts.
- `REQ-DISCOVERY-03`: validated through the explicit registration handoff back
  into `register_arxiv_source.py`.
- `REQ-DISCOVERY-04`: validated through documented
  `deepxiv_cli` / `arxiv_api` / `search_results_json` fallbacks.
- `REQ-VERIFY-01`: validated through the dedicated isolated acceptance lane and
  targeted regression slices.

## Traceability

| Requirement | Phase | Status |
|-------------|-------|--------|
| REQ-DISCOVERY-01 | Phase 143 | Complete |
| REQ-DISCOVERY-02 | Phase 143 | Complete |
| REQ-DISCOVERY-03 | Phase 143 | Complete |
| REQ-DISCOVERY-04 | Phase 143 | Complete |
| REQ-VERIFY-01 | Phase 143 | Complete |
