Stepgate is an MCP server that executes YAML stepfiles as ordered, gated procedures where each step's output must pass mechanical checks (JSON Schema, JSONLogic, or HTTP verifiers) before the agent may proceed to the next step.

The server makes all API calls and holds credentials, while the client's own model performs reasoning; the agent sees only the current step and cannot skip ahead. Every run produces a hash-chained ledger recording each step, tool call, gate verdict, and retry.