The MCP surface is exactly four control tools. They are the stable interface over a catalog that can grow independently:
| Tool | Purpose | Charges money? |
|---|---|---|
discover | Find a provider-neutral job and its catalog tools. | No |
inspect | Read one selected catalog tool's live contract. | No |
run | Execute one catalog tool and settle its charge. | Yes |
wallet | Read balance, holds and available spend. | No |
The normal loop
discover → inspect → run → walletUse tool_id as the canonical identifier. During the compatibility window, capability_id is accepted as a deprecated alias where the contract says so, but new calls should use tool_id.
What is not a control tool
Categories, capabilities, providers and catalog tools are catalog data. Connections are a human dashboard surface. Skills are agent-side recipes. None becomes a fifth MCP tool.
Start with discover, or take the complete first-run guide.