Write Authorization:${RALLY_AUTH} with no space and put the space inside the variable: some clients on Windows do not escape spaces in arguments.

The raw protocol

One JSON-RPC 2.0 message per POST, with Content-Type: application/json and Accept: application/json, text/event-stream. We always answer with application/json, never an event stream. Notifications are answered 202 with no body. Batches are refused.

Method	Era	Answer
`initialize`	Legacy	Our protocol version (yours when we support it), `tools` capability, server info, instructions
`server/discover`	Modern	`supportedVersions`, capabilities, instructions
`tools/list`	Both	Every tool with `inputSchema`, `outputSchema` and annotations
`tools/call`	Both	`content`, `structuredContent`, `isError`
`ping`	Both	An empty result

Modern requests must carry _meta["io.modelcontextprotocol/protocolVersion"]. If you also send the MCP-Protocol-Version, Mcp-Method or Mcp-Name headers they must agree with the body, or we answer 400 with error -32020. A version we do not support answers 400 with -32022 and the versions we do.

Error	Meaning
`-32700`	The body is not JSON
`-32600`	Not a single JSON-RPC request, or a batch
`-32601`	No such method (HTTP `404` in the modern era)
`-32602`	No such tool, or arguments that are not an object
`-32001`	Missing or invalid credentials (HTTP `401` with `WWW-Authenticate`)

Andre MCP-klienter | Udviklercenter