New cmd/mcpd binary using github.com/modelcontextprotocol/go-sdk
v1.5.0 over stdio transport. Exposes Lakehouse capabilities as MCP
tools: list_datasets, get_manifest, query_sql, embed_text,
search_vectors. Each tool proxies to the gateway via HTTP.
Replaces the MCP-tool subset of the Rust system's Bun mcp-server.ts
(the audit's "split this 2520-line empire" finding from R-005). HTTP
demo routes (the staffing co-pilot UI at /api/intelligence/*,
/headshots/*, etc.) stay Bun until G5 cutover — those are demo-
specific and depend on matrix-indexer signals not yet ported.
Architecture:
cmd/mcpd/main.go (235 LoC)
main() reads --gateway flag, builds server via buildServer(),
runs on StdioTransport. Each tool's args is a typed struct with
jsonschema tags (the SDK's canonical pattern); reflection
generates the JSON Schema automatically.
gatewayClient: thin HTTP wrapper over the configured gateway URL.
30s per-request timeout. 16 MiB tool-response cap. Non-2xx
surfaces as IsError CallToolResult (NOT as transport error) so
the LLM caller sees the error text and can decide how to react.
proxy() handles GET + POST + JSON body uniformly. errorResult()
+ jsonResult() helpers normalize CallToolResult shape.
cmd/mcpd/main_test.go (13 test funcs)
Tests the full MCP wire end-to-end without a subprocess: spin
up a fake gateway via httptest, build the MCP server pointed at
it, connect a client via in-memory transports (NewInMemoryTransports),
call each tool. Each tool gets:
- happy path (gateway returns 200 → tool returns content)
- input validation (missing required fields → IsError)
- upstream error (gateway 4xx → tool returns IsError)
Plus TestListTools verifies all 5 tools register; TestGatewayUnreachable
verifies network-level failures surface as IsError, not panics.
Setup for Claude Desktop / Code documented in README:
{
"mcpServers": {
"lakehouse": {
"command": "/path/to/bin/mcpd",
"args": ["--gateway", "http://127.0.0.1:3110"]
}
}
}
Verified:
go test -count=1 ./cmd/mcpd/ — 13/13 green
just verify — vet + test + 9 smokes 35s
Out of scope for this commit:
- Resources (mcp.AddResource): not needed yet; tools cover the
interactive surface. Add when an LLM-side use case shows up.
- Prompts (mcp.AddPrompt): same.
- Streamable transports (HTTP, SSE): stdio is the universal one;
streamable can be added with srv.Run(ctx, &mcp.StreamableHTTPHandler{})
swap if a daemon-mode deploy makes sense.
- mcpd inside the daemon-supervised stack: it's stdio-only and
spawned by the MCP client, not run as a service. Adding a
daemon-mode (HTTP transport on a port) is a follow-up if MCP
consumers want long-lived sessions.
This is a tool-surface only port. The Bun mcp-server.ts also serves
HTTP demo routes (/api/catalog/datasets, /intelligence/*, /headshots/*)
that depend on the matrix-indexer signals from the Rust system; those
stay Bun until G5 cutover when the staffing co-pilot service ports
to Go.
Direct deps added:
github.com/modelcontextprotocol/go-sdk v1.5.0
Transitive (resolved by go mod tidy):
github.com/google/jsonschema-go v0.4.2
github.com/yosida95/uritemplate/v3 v3.0.2
golang.org/x/oauth2 v0.35.0
github.com/segmentio/encoding v0.5.4
github.com/golang-jwt/jwt/v5 v5.3.1
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Sprint 0 / R-004 / GATE-0.4 — the 9-smoke chain is no longer
documentation only. One command (`just verify`) runs vet + tests +
all 9 smokes; pre-push hook calls it; a regression cannot leave
this machine without explicit --no-verify override.
Recipes:
just verify full gate (33s wall on this box)
just smoke <day> single smoke (d1..d6, g1, g1p, g2)
just smoke-all all 9 smokes only
just doctor dep probe with structured output
(--json for CI / pre-push)
just install-hooks install .git/hooks/pre-push
just fmt|vet|test|build|clean
scripts/doctor.sh probes Go ≥1.25, gcc, MinIO at :9000 with bucket
lakehouse-go-primary, Ollama at :11434 with nomic-embed-text loaded,
/etc/lakehouse/secrets-go.toml with [s3.primary]. Each missing dep
prints its install fix command. JSON mode emits the same shape for
CI / pre-push consumers.
README updated with the task-runner section + just install-hooks
on cold-start. Hooks live in .git/hooks/ (untracked); install
recipe recreates them on a fresh clone.
PATH note: justfile prepends /usr/local/go/bin so recipes find Go
without depending on the parent shell's PATH (ADR-001 §1.x lives
go there).
Verified: just verify exits 0 in 33s wall (vet ~0.1s + test ~0.1s +
9 smokes deterministic per audit baseline). Pre-push hook installed
and bash -n clean.
Closes audit risk R-004 (smokes not gated).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
README was stuck on "Pre-Phase G0, implementation has not started"
while we shipped through G2. Updated to reflect the current 7-binary
service inventory, the 9 acceptance smokes, the cold-start deps
(MinIO bucket, Ollama with nomic-embed-text, secrets-go.toml).
PHASE_G0_KICKOFF gains a "Post-G0 work" pointer at the end —
brief table mapping each G1+/G2 commit to its smoke + scrum-fix
count. Full per-day detail stays in commit messages and the
project memory file.
No code changes.
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>
