Method send_discover

src/mcp/client/session.py:406–436

Send a single ``server/discover`` at ``version`` and return the raw result dict. No retry, no ``adopt()``. The ``_meta`` envelope and the ``Mcp-Protocol-Version`` header are stamped at ``version`` so the server-side era router sees a coherent probe. Used by ``discover()`` an

(self, version: str)

            self._negotiated_version = result.protocol_version

    async def send_discover(self, version: str) -> dict[str, Any]:
        """Send a single ``server/discover`` at ``version`` and return the raw result dict.

        No retry, no ``adopt()``. The ``_meta`` envelope and the
        ``Mcp-Protocol-Version`` header are stamped at ``version`` so the
        server-side era router sees a coherent probe. Used by ``discover()`` and
        the connect-time auto-negotiation policy.

        Raises:
            MCPError: The server returned a JSON-RPC error, or the transport
                bounced the request at its own layer (a bare HTTP 4xx is
                synthesized into a JSON-RPC error by the transport).
        """
        client_info = self._client_info.model_dump(by_alias=True, mode="json", exclude_none=True)
        capabilities = self._build_capabilities().model_dump(by_alias=True, mode="json", exclude_none=True)
        request = types.DiscoverRequest(
            params=types.RequestParams(
                _meta={
                    PROTOCOL_VERSION_META_KEY: version,
                    CLIENT_INFO_META_KEY: client_info,
                    CLIENT_CAPABILITIES_META_KEY: capabilities,
                }
            )
        )
        data = request.model_dump(by_alias=True, mode="json", exclude_none=True)
        opts: CallOptions = {
            "timeout": DISCOVER_TIMEOUT_SECONDS,
            "cancel_on_abandon": False,
            "headers": {MCP_PROTOCOL_VERSION_HEADER: version, MCP_METHOD_HEADER: data["method"]},
        }
        return await self._dispatcher.send_raw_request(data["method"], data.get("params"), opts)

    async def discover(self) -> types.DiscoverResult:
        """Probe `server/discover` and adopt the result.