CellRank Remote Tool (MCP Server)#

TOU validation and deployment status (2026-08-16)#

CellRank dependencies, loopback discovery, and a bounded deterministic pseudotime-kernel fate call passed with aligned finite probabilities. Public publication, cross-user isolation, representative biology, broad concurrency, and recovery remain incomplete; keep this deployment private. Authenticated private Platform import and owner testing passed on 2026-08-16; public publication and independent-caller authorization/isolation remain untested.

  • Operation: run_cellrank_fate

  • Start: python -m tooluniverse.remote.cellrank.cellrank_tool

  • Endpoint: http://127.0.0.1:8028/mcp

  • Provider configuration: set TOOLUNIVERSE_REMOTE_DATA_ROOT to the provider-owned H5AD root; callers supply approved relative paths only.

  • TOU check: tu doctor --forward http://127.0.0.1:8028/mcp --json

  • Private relay: tu serve --share --forward http://127.0.0.1:8028/mcp --name validation-cellrank --workers 1

Non-loopback binding requires TOOLUNIVERSE_API_TOKEN; otherwise keep the server on loopback. The relay requires TOOLUNIVERSE_SERVICE_KEY. Public publication and independent-caller testing were not run.

New-user check: python scripts/remote_validation/setup_skill_preflight.py --implementation cellrank. Add --check-provider-env before launch, --live after launch, and --check-connect-prereqs before sharing. Live preflight checks exact MCP discovery only; it does not run or validate a model. The pinned relay SDK is not on PyPI and currently requires authorized GitHub repository access plus a configured SSH key, so a working local MCP server does not by itself prove that a new operator can share it.

The authenticated 2026-08-16 Platform matrix found all 30 private owner relays online and all 41 operations discoverable. This implementation was imported as unpublished owner draft(s), configured with a 120-second timeout, and invoked through /expert-sessions/{id}/test. Across the set, 38 unique operations passed return-schema and semantic validation; the three USPTO operations returned exact provider HTTP 403 and remain credential-blocked. Public publication, independent-caller authorization/isolation, broad saturation, and persistent supervision were not tested.

See the complete setup and verification guide.

Serves CellRank 2 (Weiler et al., Nature Methods 2024; original CellRank: Lange et al., Nature Methods 2022) — unified single-cell fate mapping — as the ToolUniverse remote tool run_cellrank_fate.

CellRank builds a Markov transition matrix over cells using a kernel, then coarse-grains it with a GPCCA estimator to find terminal macrostates and compute, for every cell, its probability of reaching each terminal state. The kernel is selectable:

  • connectivity (default) — uses only the kNN graph, so it runs on any dataset (computed automatically if neighbors are absent).

  • pseudotime — directs transitions along a precomputed pseudotime (pseudotime_key in obs, e.g. dpt_pseudotime).

  • velocity — uses RNA velocity layers (requires scVelo-computed velocity).

Served remotely (not bundled) because cellrank pulls in scanpy/anndata + scikit-learn + pyGPCCA (+ scVelo for the velocity kernel). Small datasets run on CPU.

Authorize once, then share with one short command#

After installing this provider’s dependencies and the pinned Connect relay SDK, and exporting its required resources, run once per machine (and again after key rotation):

tu remote login
# Or import an existing protected 0600 file without sourcing it:
tu remote login --env-file /path/to/tooluniverse-service.env

Then each private share is:

tu remote share cellrank

By default, tu remote login requests a short-lived device code, opens the TU Platform approval page, and polls until the signed-in user approves. No key copy/paste is required. On a headless machine, add --no-browser and open the printed link elsewhere. The CLI exchanges approval for a computer-only key, verifies /remote-servers/preflight, stores it in a local 0600 config file, and never displays it.

The share command selects the reviewed environment, checks it, starts or reuses the exact loopback MCP tool set, runs the TU Platform preflight, and keeps the private relay in the foreground until Ctrl-C. Override defaults only when needed:

tu remote share cellrank --name my-cellrank-remote --workers 1

Use tu remote run cellrank for local-only operation. Sharing does not publish a tool or prove scientific accuracy.

In an interactive terminal, sharing automatically starts the same browser flow when the key is missing, expired, or revoked. A malformed or revoked explicit TOOLUNIVERSE_SERVICE_KEY fails fast instead of being silently replaced; unset or correct it, then run tu remote login. Non-interactive jobs also fail fast. Use tu remote logout to remove only the locally stored key.

Deploy#

pip install -r requirements.txt          # cellrank + scanpy
python cellrank_tool.py                   # starts the MCP server on 127.0.0.1:8028

Input is referenced by adata_path (a server-accessible .h5ad), since single-cell matrices are large. Expose remotely only behind TOOLUNIVERSE_API_TOKEN (SMCP bind guard).

Register in ToolUniverse#

Tool definition: src/tooluniverse/data/remote_tools/cellrank_tools.json (type: RemoteTool). Connect via the standard MCPAutoLoaderTool/server_url mechanism.