Tool
Five paths the server opens on a tool container: the four MCP exchanges into the container’s own MCP server, answered with exactly one message each, and its notifications as they occur.
Five paths carry the MCP exchanges of the server into the MCP server of a tool container. The server opens each path; the proxy answers.
| Path | The server sends | The proxy sends |
|---|---|---|
/tool/list-tools | the params | exactly one response frame |
/tool/list-resources | the params | exactly one response frame |
/tool/call-tool | the params | exactly one response frame |
/tool/read-resource | the params | exactly one response frame |
/tool/notifications | nothing | one message per notification, for the life of the path |
- The first binary message is the params, on every path that has
one, as JSON read as Notation provides. The
types named from
rmcp::modelare those of the Model Context Protocol, incorporated by reference. - Every exchange is answered. Params that do not parse are answered with an error whose code is invalid params. A container whose MCP server cannot be reached is answered with an error whose code is internal error. An error the MCP server of the container itself returned is sent as that error, with its code.
- On a tool container only. The server opens these paths only on a container whose entrypoint is an MCP server.
- No repetition. An exchange whose path ended abruptly has failed. No party retries it.