MCP contract

The installed Kast MCP process runs over stdio from the client’s repository directory. After MCP negotiation, tools/list is the authority for this release’s tool names, inputSchema, and outputSchema.

Read tools	Purpose
`query_symbols`	Declarations, exact references, relations, and pipelines
`read_source`	Bounded source for an admitted selector
`check_diagnostics`	IDEA diagnostics for a path
`health_check`, `validate_workspace`	Readiness and explicit probes

add_declaration is the write tool. The App Server’s workspace_lifecycle is a separate hosted tool.

Call and result

An MCP client sends a JSON-RPC tool call after negotiation:

{
  "jsonrpc": "2.0",
  "id": 2,
  "method": "tools/call",
  "params": {"name": "health_check", "arguments": {}}
}

For a query, set name to query_symbols and use the example arguments. A call returns a JSON-RPC result with content, isError, and, when the document is admitted, structuredContent. structuredContent is the canonical operation document itself. Its status is complete, qualified, or rejected, with the operation’s exact references, coverage, finite failures, and recovery evidence intact. An invocation failure uses isError and may have no structuredContent. The generated tool call wrapper describes the MCP transport; use the generated tool response schema to decode the semantic document. The OpenAPI POST /callables/… labels in this pane organize hosted tool schemas. They are documentation paths, not HTTP endpoints. The direct MCP result uses the wrapper above.

Read the contracts

Detailed schemas

MCP contract

Call and result

​Call and result

Call and result