claude-code - 💡(How to fix) Fix [Bug] Anthropic API Error: 400 Invalid Request after /branch with concurrent tool use [1 participants]

[{"error":"Error: 1: Command failed with ERR_STREAM_PREMATURE_CLOSE: code --force --install-extension anthropic.claude-code\nPremature close \n at YW1 (/$bunfs/root/src/entrypoints/cli.js:1705:4045)\n at async AW1 (/$bunfs/root/src/entrypoints/cli.js:1705:1435)\n at processTicksAndRejections (native:7:39)","timestamp":"2026-04-22T13:27:31.765Z"},{"error":"Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"messages.105: tool_use ids were found without tool_result blocks immediately after: toolu_01C1pd1qw8yJbP79vX5NbyxG. Each tool_use block must have a corresponding tool_result block in the next message."},"request_id":"req_011CaJtRpMWuvPSmBFSBLDiY"}\n at generate (/$bunfs/root/src/entrypoints/cli.js:11:54302)\n at makeRequest (/$bunfs/root/src/entrypoints/cli.js:50:4943)\n at processTicksAndRejections (native:7:39)","timestamp":"2026-04-22T13:27:38.539Z"}]

TL;DR

The issue can likely be resolved by ensuring that each tool_use block has a corresponding tool_result block in the next message to avoid concurrency issues.

Guidance

• Review the API request payload to verify that tool_use ids are properly paired with tool_result blocks.
• Check the code that generates the API request to ensure it handles concurrency correctly and doesn't send tool_use blocks without corresponding tool_result blocks.
• Consider adding error handling to catch and retry failed requests that return a 400 error due to invalid_request_error.
• Investigate the ERR_STREAM_PREMATURE_CLOSE error to determine if it's related to the concurrency issue or a separate problem.

Example

No code snippet is provided as the issue doesn't contain sufficient information about the code.

Notes

The provided error messages suggest a concurrency issue, but the root cause may be specific to the implementation of the API client or server. Further investigation is needed to determine the exact cause.

Recommendation

Apply workaround: Ensure that each tool_use block has a corresponding tool_result block in the next message to avoid concurrency issues, as this is the most likely cause of the error.