Quirl MCP server

Run the explicitly scoped stdio server with the capabilities an MCP client actually needs:

quirl serve mcp --capabilities catalog,complete,check,format

The server is newline-delimited JSON-RPC on standard input/output. It exposes only the named tools (quirl_catalog, quirl_complete, quirl_check, and quirl_format); an ungranted tool is not callable. Source-oriented check and format requests accept bounded in-memory text only. They do not read paths, load plugins, start a shell, write files, or open the network.

Modern clients negotiate 2026-07-28 with server/discover. Every modern request must include its _meta.io.modelcontextprotocol envelope with that protocol version, client information, and client capabilities. Responses carry the matching server-information envelope, and tools/list supplies an immutable deterministic cache hint.

For existing clients, Quirl also accepts legacy initialize negotiation for 2025-03-26, 2025-06-18, and 2025-11-25, followed by the usual notifications/initialized, tools/list, and tools/call messages. A connection selects exactly one era; modern metadata and legacy negotiation cannot be mixed.

Messages and responses are limited to 1 MiB, methods to 128 UTF-8 bytes, and encoded parameters to 256 KiB. Requests allow at most 32 nested containers. Admission rejects invalid envelopes and exceeded limits before changing the connection's negotiation state. An explicit null request ID receives a response; a valid request without an ID is a notification and receives none. Malformed ID-less envelopes still receive an invalid-request error. Oversized tool results return a JSON-RPC error while the stdio connection remains usable.

MCP intentionally exposes the compiled builtin catalog only. It does not read the plugin lock, evaluate installed Lua, invoke extension callbacks, or claim that plugin commands are MCP-executable. Installed plugin metadata remains available through the validated CLI catalog, LSP, documentation, completion, and agent projections.