[BUG] tool_use ids were found without tool_result blocks

Resolved 💬 3 comments Opened Jun 16, 2025 by mattmaslin Closed Sep 18, 2025

Environment

  • Platform (select one):
  • [X ] Anthropic API
  • [ ] AWS Bedrock
  • [ ] Google Vertex AI
  • [ ] Other: <!-- specify -->
  • Claude CLI version: 1.0.24
  • Operating System: EndeavourOS
  • Terminal: allacritty

Bug Description

Using an MCP server for tracking tasks, Claude Code has become unusable and fails after making tool calls with and API Error and I cannot continue. It has blocked all work from moving forward with Claude code.
⎿ API Error: 400
{"type":"error","error":{"type":"invalid_request_error","message":"messages.5:
tool_use ids were found without tool_result blocks immediately after:
toolu_01A7FrFAeGZYCGMveVkXBMLd. Each tool_use block must have a corresponding
tool_result block in the next message."}}

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