MCP protocol surface

nene-mcp implements a subset of MCP over newline-delimited JSON-RPC on stdio.

Supported methods

Method	Description
initialize	Returns server info and capabilities
tools/list	Built-in + catalog tools
tools/call	Execute tool (builtin or HTTP-backed)
notifications/initialized	Acknowledged with no response

Unsupported methods return JSON-RPC -32601.

Built-in tool

Name	Safety	Description
nene_mcp_about	read	Package version, PHP version, resolved paths (no secrets)

Tool list shape

Each tool includes:

• name, title, description
• inputSchema (JSON Schema)
• annotations.readOnlyHint — true when safety: read

tools/call result

HTTP-backed tools return structured content:

{
  "statusCode": 200,
  "requestId": "...",
  "body": { }
}

HTTP errors set isError: true while still returning structured content.

Transport and connection failures

When the TCP/HTTP layer cannot complete a request (connection refused, DNS failure, timeout), tools/call returns a JSON-RPC error (typically -32603) with a short message — not a result object with statusCode. This differs from HTTP 4xx/5xx responses from a reachable host, which still return structured content with isError: true.

Verify NENE_MCP_API_BASE_URL with catalog smoke test before enabling write tools.

Protocol version

initialize reports protocolVersion: 2024-11-05.