Lands the matrix indexer's first piece per docs/SPEC.md §3.4:
multi-corpus retrieve+merge with corpus attribution per result.
Future components (relevance filter, downgrade gate, learning-loop
integration) layer on top of this surface.
Architecture:
- internal/matrix/retrieve.go — Retriever takes (query, corpora,
k, per_corpus_k), parallel-fans across vectord indexes, merges
by distance ascending, preserves corpus origin per hit
- cmd/matrixd — HTTP service on :3217, fronts /v1/matrix/*
- gateway proxy + [matrixd] config + lakehouse.toml entry
- Either query_text (matrix calls embedd) or query_vector
(caller pre-embedded) — vector takes precedence if both set
Error policy: fail-loud on any corpus error. Silent partial returns
would lie about coverage, defeating the matrix's whole purpose.
Bubbles vectord errors as 502 (upstream), validation as 400.
Smoke (scripts/matrix_smoke.sh, 6 assertions PASS first try):
- /matrix/corpora lists indexes
- Multi-corpus search returns hits from BOTH corpora
- Top hit is the globally-closest across all corpora
(b-near beats a-near at distance 0.05 vs 0.1 — proves merge)
- Metadata round-trips through the merge
- Distances ascending in result list
- Negative paths: empty corpora → 400, missing corpus → 502,
no query → 400
12-smoke regression sweep all green (D1-D6, G1, G1P, G2,
storaged_cap, pathway, matrix).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
