[Bug] Anthropic API Error: Tool result block missing corresponding tool use block

Resolved 💬 3 comments Opened Dec 16, 2025 by razumnyak Closed Dec 19, 2025

Bug Description
I'm trying to resume a session that was interrupted due to a long execution time.

I typed "continue" and got a 400 error.
⎿ API Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"messages.0.content.0: unexpected tool_use_id found in tool_result blocks:
toolu_01YEUFXUTB3mvkSLMrh7fniG. Each tool_result block must have a corresponding tool_use block in the previous
message."},"request_id":"req_011CW9xwfMAYPaL8t6dQRjFb"}

Last Action in claude code:

⏺ Write(tasks/epic-008/087-DEPENDENCY-<hidden>.md)

Environment Info

  • Platform: darwin
  • Terminal: vscode
  • Version: 2.0.70
  • Feedback ID: fc88fc7e-c5f8-4de1-8402-1c8de82c5bd3

Errors

[{"error":"Error: Error parsing line in /Users/<hidden>/.claude/projects/-Users-<hidden>-development-<hidden>-js/86f62c57-5f9c-4eac-8a34-c9a6262bb9f7.jsonl: SyntaxError: Unexpected non-whitespace character after JSON at position 12 (line 1 column 13)\n    at file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:75:79\n    at Array.map (<anonymous>)\n    at hm (file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:75:26)\n    at async file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:4176:3878\n    at async Promise.all (index 13)\n    at async YPA (file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:4176:3714)\n    at async file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:4176:9601\n    at async MI0 (file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:4176:203)\n    at async dm2 (file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:4176:9099)","timestamp":"2025-12-16T07:23:28.147Z"},{"error":"Error: Error parsing line in /Users/<hidden>/.claude/projects/-Users-<hidden>-development-<hidden>-js/86f62c57-5f9c-4eac-8a34-c9a6262bb9f7.jsonl: SyntaxError: Unexpected token 'u', \"uence\":nul\"... is not valid JSON\n    at file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:75:79\n    at Array.map (<anonymous>)\n    at hm (file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:75:26)\n    at async file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:4176:3878\n    at async Promise.all (index 13)\n    at async YPA (file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:4176:3714)\n    at async file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:4176:9601\n    at async MI0 (file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:4176:203)\n    at async dm2 (file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:4176:9099)","timestamp":"2025-12-16T07:23:28.147Z"},{"error":"Error: Error parsing line in /Users/<hidden>/.claude/projects/-Users-<hidden>-development-<hidden>-js/86f62c57-5f9c-4eac-8a34-c9a6262bb9f7.jsonl: SyntaxError: Unexpected token 'r', \"rt',\\n  },\"... is not valid JSON\n    at file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:75:79\n    at Array.map (<anonymous>)\n    at hm (file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:75:26)\n    at async file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:4176:3878\n    at async Promise.all (index 13)\n    at async YPA (file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:4176:3714)\n    at async file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:4176:9601\n    at async MI0 (file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:4176:203)\n    at async dm2 (file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:4176:9099)","timestamp":"2025-12-16T07:23:28.147Z"},{"error":"Error: Error parsing line in /Users/<hidden>/.claude/projects/-Users-<hidden>-development-<hidden>-js/86f62c57-5f9c-4eac-8a34-c9a6262bb9f7.jsonl: SyntaxError: Unexpected non-whitespace character after JSON at position 12 (line 1 column 13)\n    at file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:75:79\n    at Array.map (<anonymous>)\n    at hm (file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:75:26)\n    at async hZA (file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:1125:3990)\n    at async hl2 (file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:4765:294)","timestamp":"2025-12-16T07:23:29.236Z"},{"error":"Error: Error parsing line in /Users/<hidden>/.claude/projects/-Users-<hidden>-development-<hidden>-js/86f62c57-5f9c-4eac-8a34-c9a6262bb9f7.jsonl: SyntaxError: Unexpected token 'u', \"uence\":nul\"... is not valid JSON\n    at file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:75:79\n    at Array.map (<anonymous>)\n    at hm (file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:75:26)\n    at async hZA (file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:1125:3990)\n    at async hl2 (file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:4765:294)","timestamp":"2025-12-16T07:23:29.236Z"},{"error":"Error: Error parsing line 

Note: Error logs were truncated.

View original on GitHub ↗

This issue has 3 comments on GitHub. Read the full discussion on GitHub ↗