[Bug] Anthropic API Error: Missing thinking block in assistant message with extended thinking enabled

Bug Description

/context

⎿ Error: 400 {"type":"error","error":{"type":"invalid_request_err
or","message":"messages.99.content.0.type: Expected thinking
or redacted_thinking, but found text. When thinking is
enabled, a final assistant message must start with a thinking
block (preceeding the lastmost set of tool_use and
tool_result blocks). We recommend you include thinking blocks
from previous turns. To avoid this requirement, disable
thinking. Please consult our documentation at
https://docs.claude.com/en/docs/build-with-claude/extended-thin
king"},"request_id":"req_011CVHzN1UEGUAJhtKYrhJDK"}

Environment Info

• Platform: darwin
• Terminal: vscode
• Version: 2.0.46
• Feedback ID: 45ed0589-d03e-43ba-85eb-69686d252eeb

Errors

[{"error":"Error: Language not supported while highlighting code, falling back to markdown: \n    at IE (file:///Users/silouane/.nvm/versions/node/v22.15.1/lib/node_modules/@anthropic-ai/claude-code/cli.js:1105:4489)\n    at file:///Users/silouane/.nvm/versions/node/v22.15.1/lib/node_modules/@anthropic-ai/claude-code/cli.js:1105:4217\n    at Array.map (<anonymous>)\n    at QD (file:///Users/silouane/.nvm/versions/node/v22.15.1/lib/node_modules/@anthropic-ai/claude-code/cli.js:1105:4208)\n    at X32 (file:///Users/silouane/.nvm/versions/node/v22.15.1/lib/node_modules/@anthropic-ai/claude-code/cli.js:1828:3681)\n    at lq (file:///Users/silouane/.nvm/versions/node/v22.15.1/lib/node_modules/@anthropic-ai/claude-code/cli.js:105:19416)\n    at hQA (file:///Users/silouane/.nvm/versions/node/v22.15.1/lib/node_modules/@anthropic-ai/claude-code/cli.js:107:42839)\n    at p9 (file:///Users/silouane/.nvm/versions/node/v22.15.1/lib/node_modules/@anthropic-ai/claude-code/cli.js:107:38371)\n    at Na (file:///Users/silouane/.nvm/versions/node/v22.15.1/lib/node_modules/@anthropic-ai/claude-code/cli.js:107:38299)\n    at BN (file:///Users/silouane/.nvm/versions/node/v22.15.1/lib/node_modules/@anthropic-ai/claude-code/cli.js:107:38153)","timestamp":"2025-11-19T18:09:48.753Z"},{"error":"Error: Language not supported while highlighting code, falling back to markdown: \n    at IE (file:///Users/silouane/.nvm/versions/node/v22.15.1/lib/node_modules/@anthropic-ai/claude-code/cli.js:1105:4489)\n    at file:///Users/silouane/.nvm/versions/node/v22.15.1/lib/node_modules/@anthropic-ai/claude-code/cli.js:1105:4217\n    at Array.map (<anonymous>)\n    at QD (file:///Users/silouane/.nvm/versions/node/v22.15.1/lib/node_modules/@anthropic-ai/claude-code/cli.js:1105:4208)\n    at X32 (file:///Users/silouane/.nvm/versions/node/v22.15.1/lib/node_modules/@anthropic-ai/claude-code/cli.js:1828:3681)\n    at lq (file:///Users/silouane/.nvm/versions/node/v22.15.1/lib/node_modules/@anthropic-ai/claude-code/cli.js:105:19416)\n    at hQA (file:///Users/silouane/.nvm/versions/node/v22.15.1/lib/node_modules/@anthropic-ai/claude-code/cli.js:107:42839)\n    at p9 (file:///Users/silouane/.nvm/versions/node/v22.15.1/lib/node_modules/@anthropic-ai/claude-code/cli.js:107:38371)\n    at Na (file:///Users/silouane/.nvm/versions/node/v22.15.1/lib/node_modules/@anthropic-ai/claude-code/cli.js:107:38299)\n    at BN (file:///Users/silouane/.nvm/versions/node/v22.15.1/lib/node_modules/@anthropic-ai/claude-code/cli.js:107:38153)","timestamp":"2025-11-19T18:09:48.755Z"},{"error":"Error: Language not supported while highlighting code, falling back to markdown: \n    at IE (file:///Users/silouane/.nvm/versions/node/v22.15.1/lib/node_modules/@anthropic-ai/claude-code/cli.js:1105:4489)\n    at file:///Users/silouane/.nvm/versions/node/v22.15.1/lib/node_modules/@anthropic-ai/claude-code/cli.js:1105:4217\n    at Array.map (<anonymous>)\n    at QD (file:///Users/silouane/.nvm/versions/node/v22.15.1/lib/node_modules/@anthropic-ai/claude-code/cli.js:1105:4208)\n    at X32 (file:///Users/silouane/.nvm/versions/node/v22.15.1/lib/node_modules/@anthropic-ai/claude-code/cli.js:1828:3681)\n    at lq (file:///Users/silouane/.nvm/versions/node/v22.15.1/lib/node_modules/@anthropic-ai/claude-code/cli.js:105:19416)\n    at hQA (file:///Users/silouane/.nvm/versions/node/v22.15.1/lib/node_modules/@anthropic-ai/claude-code/cli.js:107:42839)\n    at p9 (file:///Users/silouane/.nvm/versions/node/v22.15.1/lib/node_modules/@anthropic-ai/claude-code/cli.js:107:38371)\n    at Na (file:///Users/silouane/.nvm/versions/node/v22.15.1/lib/node_modules/@anthropic-ai/claude-code/cli.js:107:38299)\n    at BN (file:///Users/silouane/.nvm/versions/node/v22.15.1/lib/node_modules/@anthropic-ai/claude-code/cli.js:107:38153)","timestamp":"2025-11-19T18:09:48.756Z"},{"error":"Error: Language not supported while highlighting code, falling back to markdown: \n    at IE (file:///Users/silouane/.nvm/versions/node/v22.15.1/lib/node_modules/@anthropic-ai/claude-code/cli.js:1105:4489)\n    at file:///Users/silouane/.nvm/versions/node/v2

Note: Error logs were truncated.