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loopctl

`src/mcp.rs` — the MCP client side [feature: mcp]

Connect to MCP servers, discover their tools, adapt them as loopctl tools. Built on the rmcp library (hidden from the public client surface).

Key items

  • McpClient — stdio(CommandSpec), http_sse(endpoint) (+ http_sse_with_client), in_process(server), from_service(...); reconnect(&StreamRetryConfig).
  • CommandSpec { program, args, env, cwd } — struct-literal construction.
  • McpToolProvider::connect(client, name_prefix) — snapshots the server’s tools; register_into(&mut registry); with_call_timeout (default 60s); refresh(); tools(); client().
  • McpTool — the adapted Tool: server schema verbatim, is_concurrency_safe false, is_read_only from readOnlyHint.
  • McpError — Handshake / Protocol / EmptyToolError.

Behavior notes

  • The prefix namespaces names client-side (prefix__tool); the un-prefixed name is what tools/call forwards.
  • Call timeout exceeded → soft error naming tool and budget — a wedged server costs one result, not the loop.
  • Stdio children die with the client handle (rmcp kills, 3s grace); in-process needs a tokio runtime and can’t reconnect.
  • Refresh doesn’t retro-update already-registered tools; duplicate names after prefixing collapse (first kept).

Deep dive: MCP.