claude-code - 💡(How to fix) Fix [Bug] Anthropic API Error: 400 Tool Use Concurrency Issue Blocks Conversation Recovery [1 participants]

[{"error":"Error: Tool mcp__claude_ai_Slite__ask-slite not found\n at c97 (/$bunfs/root/src/entrypoints/cli.js:3090:31272)\n at jD (/$bunfs/root/src/entrypoints/cli.js:477:21022)\n at IO (/$bunfs/root/src/entrypoints/cli.js:477:39569)\n at vh (/$bunfs/root/src/entrypoints/cli.js:477:50270)\n at rBH (/$bunfs/root/src/entrypoints/cli.js:477:86946)\n at nBH (/$bunfs/root/src/entrypoints/cli.js:477:85908)\n at wTH (/$bunfs/root/src/entrypoints/cli.js:477:85729)\n at cBH (/$bunfs/root/src/entrypoints/cli.js:477:82086)\n at cH (/$bunfs/root/src/entrypoints/cli.js:477:6377)\n at Ap6 (/$bunfs/root/src/entrypoints/cli.js:470:6902)","timestamp":"2026-04-29T11:10:27.239Z"},{"error":"Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"messages.5: tool_use ids were found without tool_result blocks immediately after: toolu_01Rhf56T5ACxeQoFv3xNs9hv. Each tool_use block must have a corresponding tool_result block in the next message."},"request_id":"req_011CaXxdjYPUjW29pL9EBZoy"}\n at generate (/$bunfs/root/src/entrypoints/cli.js:11:54074)\n at makeRequest (/$bunfs/root/src/entrypoints/cli.js:50:4943)\n at processTicksAndRejections (native:7:39)","timestamp":"2026-04-29T11:10:30.396Z"},{"error":"Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"messages.5: tool_use ids were found without tool_result blocks immediately after: toolu_01Rhf56T5ACxeQoFv3xNs9hv. Each tool_use block must have a corresponding tool_result block in the next message."},"request_id":"req_011CaXxfUWpG28BhCarTg2pd"}\n at generate (/$bunfs/root/src/entrypoints/cli.js:11:54074)\n at makeRequest (/$bunfs/root/src/entrypoints/cli.js:50:4943)\n at processTicksAndRejections (native:7:39)","timestamp":"2026-04-29T11:10:53.870Z"},{"error":"Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"messages.5: tool_use ids were found without tool_result blocks immediately after: toolu_01Rhf56T5ACxeQoFv3xNs9hv. Each tool_use block must have a corresponding tool_result block in the next message."},"request_id":"req_011CaXxh54yT9avpo2i6bjh6"}\n at generate (/$bunfs/root/src/entrypoints/cli.js:11:54074)\n at makeRequest (/$bunfs/root/src/entrypoints/cli.js:50:4943)\n at processTicksAndRejections (native:7:39)","timestamp":"2026-04-29T11:11:15.558Z"},{"error":"Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"messages.5: tool_use ids were found without tool_result blocks immediately after: toolu_01Rhf56T5ACxeQoFv3xNs9hv. Each tool_use block must have a corresponding tool_result block in the next message."},"request_id":"req_011CaXxkWndXdj3D4dmgcSiQ"}\n at generate (/$bunfs/root/src/entrypoints/cli.js:11:54074)\n at makeRequest (/$bunfs/root/src/entrypoints/cli.js:50:4943)\n at processTicksAndRejections (native:7:39)","timestamp":"2026-04-29T11:12:02.229Z"}]

TL;DR

Run the /rewind command to recover the conversation and resolve the API Error 400 due to tool use concurrency issues.

Guidance

• The error messages indicate a tool_use id without a corresponding tool_result block, suggesting a synchronization issue.
• The /rewind command may help resolve this by reinitializing the conversation state.
• Verify that the tool_use and tool_result blocks are properly paired in the conversation history.
• If the issue persists, check for any concurrent modifications to the conversation state that may be causing the synchronization issue.

Example

No code snippet is provided as the issue seems to be related to the conversation state and tool usage, rather than a specific code error.

Notes

The provided error messages and guidance are based on the assumption that the /rewind command is a valid solution to resolve the conversation state and tool use concurrency issues. If this command is not available or does not resolve the issue, further investigation into the conversation history and tool usage may be necessary.

Recommendation

Apply the workaround by running the /rewind command to recover the conversation and resolve the API Error 400. This is recommended as it is explicitly suggested in the error message and may provide a quick resolution to the issue.