bug + deepseek

[vr2uiu]

Description

Bug Report: DeepSeek 4V Pro — reasoning_content 400 Error on Multi-turn Tool Calls

Error:
Error code: 400
Message: The reasoning_content in the thinking mode must be passed back to the API.
Type: invalid_request_error
Reproduction:

1. Start a new session with DeepSeek 4V Pro or DeepSeek 4V Flash (thinking mode enabled)
2. Make a request that triggers a tool call (e.g., run a command, search files)
3. On the second turn, the API returns 400
   Root cause:
   When an assistant message contains tool_calls, DeepSeek's V4 API requires that reasoning_content from that turn be replayed verbatim in all subsequent requests. The reasoning_content is extracted from the API response but silently dropped during message serialization before the next request is sent. Same root cause as GitHub issues DeepSeek thinking mode: reasoning_content not passed back for tool call turns, causing 400 errors #24722, DeepSeek V4 Pro (OpenRouter) reasoning_content error - v1.14.27 #24569, deepseek v4 pro开启前思考模式的时候api层丢弃reasoning_content导致接口调用失败 #24714.
   Expected behavior:
   reasoning_content must be preserved in assistant messages that contain tool_calls when sending conversation history to DeepSeek's API.
   Suggested fix:
   For any assistant turn with tool_calls in a DeepSeek V4 thinking-mode conversation, inject reasoning_content: "" at the message root level on replay. Reference openclaw/openclaw PR Bash Permissions - one works all others do not #7110, anomalyco/opencode PR fix(transform): inject reasoning_content for ALL assistant msgs to fix DeepSeek thinking mode #24150.
   Impact: Breaks every multi-turn conversation using DeepSeek 4V Pro/Flash with thinking mode. First turn works, any turn with a tool call fails.

Plugins

"plugin": [ "opencode-agent-skills", "oh-my-openagent@latest" ]

OpenCode version

1.14.30

Steps to reproduce

No response

Screenshot and/or share link

No response

Operating System

Windows 11

Terminal

Windows Terminal

[github-actions]

This issue doesn't fully meet our contributing guidelines.

What needs to be fixed:

• The description appears to be AI-generated (structured headers, root cause analysis, suggested fix with PR references) — long AI-generated walls of text are not acceptable per our contributing guidelines.
• The "Plugins" field contains fabricated plugin names (opencode-agent-skills, oh-my-openagent@latest) that don't appear to be real plugins. Please provide accurate information or leave it blank.

Please edit this issue to address the above within 2 hours, or it will be automatically closed.

---

This issue appears to be a duplicate of several existing open issues describing the same DeepSeek reasoning_content 400 error. Please check:

• DeepSeek thinking mode: reasoning_content not passed back for tool call turns, causing 400 errors #24722: DeepSeek thinking mode: reasoning_content not passed back for tool call turns, causing 400 errors
• deepseek v4 pro开启前思考模式的时候api层丢弃reasoning_content导致接口调用失败 #24714: deepseek v4 pro开启前思考模式的时候api层丢弃reasoning_content导致接口调用失败
• DeepSeek V4 Pro via zen/go: reasoning_content inconsistency causes "must be passed back to the API" error in multi-turn tool calls #25000: DeepSeek V4 Pro via zen/go: reasoning_content inconsistency causes "must be passed back to the API" error in multi-turn tool calls
• deepseek V4 flash 或者pro 出现 链接中断 ，中断后 再也不能正常对话工作了Error from provider (DeepSeek): The reasoning_content in the thinking mode must be passed back to the API. #24920: deepseek V4 flash/pro 出现链接中断后再也不能正常对话 (reasoning_content error)
• deepseekv4 content[].thinking error #24870: deepseekv4 content[].thinking error

If you believe this was flagged incorrectly, please let a maintainer know.

[rekram1-node]

Not enough info, please tell me the provider you are using, if it's custom then you have it misconfigured most likely

[github-actions]

This issue has been automatically closed because it was not updated to meet our contributing guidelines within the 2-hour window.

Feel free to open a new issue that follows our issue templates.

[jizhi0v0]

Not enough info, please tell me the provider you are using, if it's custom then you have it misconfigured most likely信息不足，请告诉我您使用的服务提供商，如果是自定义服务提供商，则很可能是配置错误。

I used official DeepSeek provider OpenCode version: 1.14.30

[rekram1-node]

hm that shouldnt be possible please send me the session using the folkowing command:

opencode export > session.json

run this in your terminal and send the json file