Per J 2026-04-25 architectural correction: matrix index is the vector
indexing layer for the WHOLE knowledge base (distilled facts, procedures,
config hints, team runs, playbooks, pathway successes), not a single
narrow store. Built fetchMatrixContext(query, taskClass, filePath) that:
- Queries multiple persistent vector indexes in parallel via /vectors/search
- Collects hits per corpus + score + doc_id + 400-char excerpt
- Pulls pathway successes via existing helper, mapped to MatrixHit shape
- Sorts by score across corpora, returns top-N (default 8)
- Reports per-corpus hit counts + errors for transparency
Per-task-class corpus list (MATRIX_CORPORA_FOR_TASK):
scrum_review → distilled_factual, distilled_procedural,
distilled_config_hint, kb_team_runs_v1
(staffing data deliberately excluded — not relevant to code review)
Probed live: distilled_config_hint top hit = 0.52, distilled_procedural
top = 0.49, kb_team_runs top = 0.59. Real signal across corpora.
Replaces the narrow proven-approaches preamble with a unified
MATRIX-INDEXED CONTEXT preamble tagged with source_corpus per chunk
so the model knows what kind of context it's seeing.
LH_SCRUM_MATRIX_RETRIEVE=0 still disables for A/B testing.
Future: promote to a Rust /v1/matrix endpoint once corpora list and
ranking logic stabilize. For now TS lets us iterate fast against the
live matrix without gateway restarts.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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