v0.42.1

0.42.1 (2026-07-23)

Bug Fixes

• mcp: wrap responses with Content-Length framing (stdio transport spec) The MCP stdio transport spec requires both directions to use Content-Length framing. _mcp_read_message already handles framed input (from #442), but responses were still written as bare newline-delimited JSON. Clients like Kiro and VS Code Copilot that strictly follow the spec could not parse the unframed responses, resulting in 'no tools' after a successful handshake. Add _mcp_write() that prepends 'Content-Length: N\r\n\r\n' to every response body. Update _mcp_respond and _mcp_error to use it. The output format is now: Content-Length: 36\r\n\r\n{"jsonrpc":"2.0","id":1,"result":{}} Add two tests asserting Content-Length output framing and byte-count accuracy. Closes #468 (#469) (97bf162)