Claude SDK Debugging

JSON serialization errors in Claude SDK typically stem from TypedDict contract mismatches in MCP server configuration. The SDK expects specific fields like `type="sdk"` in McpSdkServerConfig structures; missing or mistyped fields cause serialization to fail. Examine your full error traceback to locate the exact field name mismatch in your ClaudeAgentOptions.mcp_servers configuration.

Extract the complete error traceback from your logs and locate the SDK source code that validates TypedDict contracts. Compare your MCP server configuration against the expected schema for McpSdkServerConfig and ClaudeAgentOptions.mcp_servers. Verify key names, field types, and required vs. optional fields match exactly what the SDK's internal processing logic expects.

Internal SDK errors arise when configuration objects lack required TypedDict fields or contain incompatible data types. Common causes include missing `type` field values, instance stripping mismatches, or JSON serialization of non-serializable objects. Systematic traceback analysis reveals which SDK module failed and what contract violation triggered it.

Implement targeted tests that serialize your McpSdkServerConfig and ClaudeAgentOptions.mcp_servers objects to JSON, then validate the output against the SDK's TypedDict schema. Run end-to-end tests with your Claude Agent to confirm configuration loads without serialization errors and internal processing succeeds.

Yes. Most SDK errors resolve through configuration fixes alone: correcting TypedDict field names, adding missing required fields, or ensuring proper data types in MCP server config. Only if the error originates in SDK logic itself—not your configuration—would you need to file an issue or patch the SDK dependency.

Extract the full traceback rather than relying on user-facing error summaries, which hide root causes. Locate the exact line in SDK source code where the error occurred, then trace backwards through the code to identify which TypedDict contract was violated or which serialization step failed in your configuration.