The protocol-derived headers for an outgoing message: the
MCP-Protocol-Version header plus, for a draft client, the standard
Mcp-Method / Mcp-Name headers and any Mcp-Param-* mirrored tool
arguments. Called with Json.undefined (no message — e.g. the GET server
stream) it returns only the version header. Never includes Accept /
Content-Type / Authorization / Mcp-Session-Id / Last-Event-ID — those are
the transport's own.
The protocol-derived headers for an outgoing message: the MCP-Protocol-Version header plus, for a draft client, the standard Mcp-Method / Mcp-Name headers and any Mcp-Param-* mirrored tool arguments. Called with Json.undefined (no message — e.g. the GET server stream) it returns only the version header. Never includes Accept / Content-Type / Authorization / Mcp-Session-Id / Last-Event-ID — those are the transport's own.