Adds matrix indexer as its own row in the §1 component table and a
new §3.4 with port plan. Distinct from vectord (substrate); lives at
internal/matrix/ + gateway /v1/matrix/*.
Five components in dependency order: corpus builders → multi-corpus
retrieve+merge → relevance filter → strong-model downgrade gate →
learning-loop integration.
Locks in the framing J flagged 2026-04-29: in Rust the matrix indexer
was emergent across mode.rs + build_*_corpus.ts + observer /relevance,
and earlier port-planning reduced it to "we have vectord." The SPEC
now names it explicitly so the port preserves the multi-corpus
retrieval shape AND the learning loop, not just the HNSW substrate.
Sharding-by-id was investigated as a throughput fix and rejected —
corpus-as-shard at the matrix layer is the existing retrieval shape
and parallelizes Adds for free.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Pre-Phase-G0 research sweep against current Go ecosystem state. Three
upstream changes that the day-of SPEC missed:
1. DuckDB Go binding ownership transferred. marcboeker/go-duckdb is
deprecated as of v2.5.0 — official maintainer is now
github.com/duckdb/duckdb-go/v2 (DuckDB team + Marc Boeker joint
hand-off). Current v2.10502.0 / DuckDB v1.5.2. SPEC §3.1 +
component table updated.
2. Official Go MCP SDK exists. Switching from mark3labs/mcp-go
(community) to github.com/modelcontextprotocol/go-sdk (official,
Google collaboration, v1.5.0 stable, 4.4k stars, targets MCP spec
2025-11-25). Component table updated.
3. arrow-go is on v18, not v15. v18.5.2 (March 2026) has parquet
encryption fixes relevant for PII-masked safe views. PRD locked
stack + SPEC component table updated.
Validated unchanged: coder/hnsw (220 stars, active), chi (still the
clean-architecture pick over fiber/gin/echo).
Surfaced for future use: anthropics/anthropic-sdk-go (official,
available for direct Claude calls bypassing opencode if ever needed),
duckdb-wasm (browser-side analytics future option), IVF as HNSW
fallback if recall gate fails.
See docs/RESEARCH_LOG_2026-04-28.md for full survey + sources.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Two documents only — no Go code yet. PRD restates the problem and
preserves the Rust PRD's invariants verbatim, then maps the locked
stack to Go libraries and surfaces four hard problems (DuckDB-via-cgo
for the query engine, Lance dropped, Dioxus → HTMX, arrow-go maturity).
SPEC walks each Rust crate + TS surface and tags the port with library
choice / effort estimate / risk + a 5-phase migration plan from
skeleton (Phase G0) to demo parity (Phase G5).
Six open questions remain that gate Phase G0:
- DuckDB cgo OK?
- HTMX vs React for the UI?
- Repo location?
- Distillation v1.0.0 port verbatim or rebuild?
- Pathway memory data — port 88 traces or start clean?
- Auditor lineage — port audit_baselines.jsonl or restart?
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
