smalt-mcp 1.2.0

MCP server wrapping the Smalt's storage surface (read/write/link/claim/search) for ParkviewLab's CoGrind project.

smalt-mcp

MCP server wrapping the Smalt's storage surface (read / write / link / claim / search) for ParkviewLab's CoGrind project. Thinnest viable wrapper around markdown + LanceDB; no agentic logic. Single-writer to a given Smalt.

To cobalt-grinding what deco-assaying is to tree-sitter: a clean MCP-shaped wrapper around a deterministic capability.

Status

Storage substrate complete. The full storage-substrate surface is wired up: 17 tools across three permission tiers, with auto-indexer-trigger on writes and hybrid (FTS + vector + alias, RRF-fused) search. Track A of CoGrind's M2.7 plan — see cobalt-grinding/docs/plan.md for the full design.

The scientific-method surface (proposals / experiments / gaps) is not part of smalt-mcp — it lives in a separate MCP server, ebony-enriching, the lab-notebook substrate. Cobalt-grinding's cognitive systems read from both substrates and orchestrate cross-substrate writes.

Run

Same five-mode pattern as deco-assaying. Pick whichever fits.

Mode	When to use
1. uvx (one-off)	Try it once, no install.
2. uv tool install (pinned daemon)	Run it occasionally, want it on $PATH.
3. macOS LaunchAgent	Persistent daemon on a Mac.
4. Linux systemd user unit	Persistent daemon on Linux.
5. Docker / docker compose	Container deployment.

In every mode the server listens on PORT (default 35833). Sanity-check:

curl http://127.0.0.1:35833/health

From source (current; until first release)

git clone https://github.com/ParkviewLab/smalt-mcp.git
cd smalt-mcp
uv sync
SMALT_DIR=~/Documents/Smalt uv run python -m smalt_mcp

Docker (after first release)

docker pull ghcr.io/parkviewlab/smalt-mcp:latest
docker run --rm \
  -p 35833:35833 \
  -e SMALT_SCOPE=read_only \
  -v smalt-data:/data \
  ghcr.io/parkviewlab/smalt-mcp:latest

Or use docker-compose.yml.

Endpoints

• POST /sse — MCP Streamable HTTP transport. Tools.
• GET /health — liveness probe ({ok, version, uptime_seconds}).
• GET /admin/version — server identity + scope + configured Smalt path.
• GET /docs — OpenAPI / Swagger UI for the HTTP routes.

HTTP responses are gzipped when the client sends Accept-Encoding: gzip.

MCP tools

Three permission tiers controlled by SMALT_SCOPE. A caller at tier N sees and may call any tool whose required scope is ≤ N.

read_only (8 tools):

• status — Smalt path, existence, LanceDB tables, page count, single-writer mutex state, embedding provider.
• list_pages — indexed pages, filtered by type / prefix.
• read_page — full page (frontmatter + body); falls back to alias lookup on miss.
• find_by_alias — every page whose aliases list contains the given alias.
• incoming_links — "what links to this page" (the inverse of traverse).
• traverse — outgoing edges from a page; optional label filter.
• search — hybrid FTS + vector + alias, RRF-fused; every hit carries id, aliases, title, type, snippet, score.
• list_domains — ConceptPages flagged is_domain: true.

read_write (+5 tools):

• bootstrap — initialize the canonical layout + LanceDB tables; idempotent.
• write_page — create (always-mangle: caller-id becomes slug-prefix + 22-char UUID4 suffix; original id preserved in aliases) or update (requires existing canonical id). Runs the incremental indexer.
• write_pages — batch of writes; validate-all-then-act; single indexer pass at the end.
• add_link — append an outgoing link to a page's links_out; duplicate detection.
• add_claim — append a Claim to a page's claims; duplicate-id detection.

remove_destructive (+4 tools):

• remove_page — cascading delete (file + pages row + embeddings row + outgoing + incoming links + claims).
• update_claim — replace one claim by id; new_claim.id must equal claim_id.
• remove_claim — remove one claim by id.
• remove_link — remove edges by (from_id, to_id, label?); omit label to drop every edge between the pair.

For the proposal / experiment / gap surface (writing hypotheses, recording experiment runs, queueing knowledge gaps), use ebony-enriching — the lab-notebook substrate. Both servers are independent: cobalt-grinding's cognitive systems orchestrate any cross-substrate flow.

Configuration

Env var	Default	Purpose
PORT	35833	HTTP listen port.
HOST	0.0.0.0	HTTP bind address.
SMALT_DIR	~/Documents/Smalt	Path to the Smalt this server wraps. Call the bootstrap MCP tool once to initialize.
SMALT_SCOPE	read_write	read_only, read_write, or remove_destructive. Tiered: caller at tier N sees every tool whose required scope is ≤ N.
EMBEDDING_PROVIDER	fastembed	Embedding backend. fastembed is the only one wired up; voyage / openai are placeholders.
EMBEDDING_MODEL	BAAI/bge-small-en-v1.5	Model name passed to the provider.
EMBEDDING_DIM	384	Must match the model.
SMALT_INTERNAL_TOKEN	(unset)	Reserved for future per-client scope routing; not yet enforced.

Operations: backup and restore

The Smalt is a directory of markdown files (plus a rebuildable LanceDB index). Use Restic directly against SMALT_DIR for backup — there's no dedicated backup endpoint on the server, and it's intentional: Restic's content-defined chunk-level deduplication needs to see raw file content. Pointing it at the live directory gives real per-file dedup, real incremental snapshots, and a restore-as-directory-tree workflow that's strictly better than any server-side archive-export endpoint would deliver.

Backup

restic backup "$SMALT_DIR" --exclude "index/lance"

Excluding index/lance/ is the recommended default — the LanceDB store is rebuildable from the markdown in pages/. Including it would roughly double snapshot size with bytes that the indexer can regenerate post-restore.

You can run this against a live smalt-mcp (the server only holds the corpus mutex briefly, during the commit phase of a write). For a strictly point-in-time snapshot, stop the server first.

Restore

# 1. Stop smalt-mcp (otherwise it could race the restore).
# 2. Restore from the latest snapshot to a staging dir.
restic restore latest --target /staging

# 3. Move the restored Smalt into place.
mv /staging/<path-restic-recorded>/Smalt "$SMALT_DIR"

# 4. Start smalt-mcp pointing at the restored SMALT_DIR.
SMALT_DIR="$SMALT_DIR" uv run python -m smalt_mcp   # or your usual run mode

Then trigger an index rebuild via the MCP bootstrap tool. bootstrap is idempotent — it'll detect the restored markdown and rebuild the LanceDB index from it (since we excluded index/lance/ from the backup). A planned future tool (reindex_all) will be the cleaner explicit version of this for the restore use case; until it ships, bootstrap is the right call.

Remote Smalts (running on a host where Restic can't reach the filesystem)

Mount SMALT_DIR locally via SSHFS (or equivalent), then restic backup against the mount. Same per-file dedup as the local case, with one extra hop. If even SSHFS isn't possible (very restricted deployment), the prior approach of building a tar.gz server-side and piping to restic backup --stdin is technically possible but defeats Restic's dedup — every snapshot becomes one opaque binary blob. Not recommended.

Why no /admin/backup endpoint

Earlier iterations of smalt-mcp briefly shipped a GET /admin/backup streaming tar.gz endpoint. It was removed in v0.12.0 after we realized the Restic-native pattern is strictly better for the common case. The endpoint design (streaming tar.gz via stdlib tarfile, best-effort consistency, scope-filtered downloads) was sound; the question was whether to ship a half-good answer (opaque blob, zero dedup) or the right answer (Restic against the filesystem). We chose the latter.

Releasing

Tag-driven via the release workflow on push of a v* tag. Use the ParkviewLab/dev-tools helpers — they enforce the SSOT-tag-CI loop (pyproject.toml is the only place the version lives; CI verifies the pushed tag matches before publishing).

git bump patch              # 0.1.5 → 0.1.6, committed
git release                 # annotated tag v0.1.6 from pyproject.toml
git push --follow-tags      # CI fires

Don't have the helpers? Install once: git clone https://github.com/ParkviewLab/dev-tools.git ~/dev-tools && cd ~/dev-tools && ./install.sh.

License

MIT. See LICENSE.