MCP Python SDK 2.1.0 · quieter handler errors, leaner content returns

v2.1.0 (24 Aug): Client takes StdioServerParameters directly. Unexpected tool/resource/prompt exceptions now log once server-side and return only Error executing tool <name> to the client — raise ToolError / ResourceError when the model should see the message.⁵ Tools annotated to return TextContent / Image / Audio (or lists) no longer advertise outputSchema or fill structuredContent; pass structured_output=True to keep the old shape.⁵ 4 MiB body limit extends to SSE and OAuth. v1.29.1 is the maintenance line with the body-limit and recursive-schema fixes.⁶

Relevant to: anyone shipping MCP servers or clients on the Python SDK