cellc-mcp

MCP server wrapping the cellc CellScript compiler so a local agentic model can write CKB Cell contracts in a write → check → explain → inspect loop.

Install

python -m venv .venv && . .venv/bin/activate
pip install -e .

Related MCP server: Rust Coder

Requirements

• A built cellc binary. Build it once: cd ~/CellScript && cargo install --path . (Needs a sibling ckb-sdk-rust checkout at tag v5.1.0 per CellScript AGENTS.md.)

Configuration (env)

• CELLC_BIN — path to the cellc binary (else found on PATH)

• CELLSCRIPT_REPO — CellScript checkout for examples/reference (default ~/CellScript)

• CELLC_TIMEOUT — per-call timeout seconds (default 30)

MCP client config

{
  "mcpServers": {
    "cellc": {
      "command": "cellc-mcp",
      "env": { "CELLSCRIPT_REPO": "/home/phill/CellScript" }
    }
  }
}

Tools

• cellc_check — type-check; terse diagnostics (max 5; full=true for all)

• cellc_explain — explain an error code (E####)

• cellc_metadata — compiler metadata summary (full=true for schema-30 JSON)

• cellc_constraints — verifier obligations + runtime-error registry

• cellc_language_reference — the full language surface, in-context

• cellc_list_examples / cellc_get_example — example contracts for grounding

Tests

python -m pytest -v                 # offline unit tests
python -m pytest -m needs_cellc -v  # integration (needs cellc)