v0.33.1

Compatibility with json 3.x and mcp 1.x. Upgrade if your bundle resolves json 3.x — rename_session / tag_session raise on 0.33.0.

Changed

• mcp dependency is now >= 0.20, < 2 (was >= 0.6, < 1). The floor moves to 0.20 because mcp 0.19 and older validate through the json-schema gem, which breaks under json 3.x and fails every SDK MCP tools/call; with json 2.x those versions still pass, so this only forces an mcp upgrade on bundles pinned below 0.20. The suite passes against every 1.x release through 1.6.0, and initialize / tools/list / tools/call / resources/* / prompts/* wire output is byte-identical to 0.2x.
• SDK MCP tool handler exceptions now reach the model as the bare exception message (matching Python's str(e) and SdkMcpServer#call_tool) instead of the gem's Internal error calling tool X: msg. The exception is rescued inside the SDK's tool class, so the text no longer depends on the mcp gem version — mcp 1.2+ redacts the message from its own wrapper, which would otherwise have left the model with no error text to self-correct from. Still in-band isError: true.

Fixed

• rename_session / tag_session raised ArgumentError: unknown keyword: space_size under json 3.x, which takes generator options as strict keywords. The option was a no-op on json 2.x (output unchanged), so it is simply gone. A fresh end-user bundle resolves json 3.x through async → console → json; CI missed it only because the dev-only RuboCop pin holds json at 2.x.

What's changed

• #64 Support mcp 1.x and json 3.x — @ya-luotao

Full Changelog: v0.33.0...v0.33.1

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gem install claude-agent-sdk -v 0.33.1