gas-mcp

gas-mcp is the generic MCP transport for a gas_protocol.service.GasService. It turns one GAS service into an MCP server without knowing which domain, database, policy implementation, or application created that service.

What it provides

install_gas_mcp(server, service) registers five structured-output MCP tools:

• create_session — create an isolated session and return its initial view.
• get — read a resource URI and its contextual commands and links.
• search — search a resource collection.
• act — execute an advertised capability with a revision and idempotency key.
• why_not — diagnose an unavailable command without returning an executable command.

The installer adds read-only or mutation tool annotations and translates GasError failures into MCP errors. Domain-specific resource names and input schemas stay in the GasBackend and its composition root.

The package provides transport only. The GAS request/response contract and capability semantics remain defined by gas-protocol; authorization and domain policy remain with the backend or application that supplies the service.

Install

pip install "gas-mcp[mcp]"

The mcp extra supplies the MCP SDK needed to import and run the transport.

Example

from mcp.server import MCPServer

from gas_mcp import install_gas_mcp
from gas_protocol import GasService, InMemoryGasBackend

server = MCPServer(name="example")
install_gas_mcp(server, GasService(InMemoryGasBackend()))

For a real application, construct the GasService over its own backend and keep domain-specific MCP resources in that application's composition root.

Contributing

uv build
uv run --extra mcp --with pytest pytest -q