Error from provider (DeepSeek): The `reasoning_content` in the thinking mode must be passed back to the API.

[agarwalbikram]

Description

{ "name": "APIError", "data": { "message": "Error from provider (DeepSeek): The reasoning_contentin the thinking mode must be passed back to the API.", "statusCode": 400, "isRetryable": false, "responseHeaders": { "cf-ray": "9f1e8cb56dd8a8fe-CMH", "connection": "keep-alive", "content-length": "207", "content-type": "application/json", "date": "Sat, 25 Apr 2026 15:58:32 GMT", "server": "cloudflare" }, "responseBody": "{\"error\":{\"message\":\"Error from provider (DeepSeek): Thereasoning_content in the thinking mode must be passed back to the API.\",\"type\":\"invalid_request_error\",\"param\":null,\"code\":\"invalid_request_error\"}}", "metadata": { "url": "https://opencode.ai/zen/go/v1/chat/completions" } } }

Plugins

KiloCode with VsCode Ide using opencode API

OpenCode version

I use KiloCode

Steps to reproduce

Just normal Promot in KiloCode

Screenshot and/or share link

Operating System

MacOs

Terminal

[github-actions]

This issue doesn't fully meet our contributing guidelines.

What needs to be fixed:

• Steps to reproduce are missing (_No response_)
• OpenCode version, Operating System, and Terminal fields are all empty — this context is needed to triage and fix the bug

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

---

This issue might be a duplicate of existing issues. Please check:

• Bug: DeepSeek reasoning_content not passed back in multi-turn conversations #24261: Bug: DeepSeek reasoning_content not passed back in multi-turn conversations
• [DeepSeek V4] reasoning_content not round-tripped — 400 error on multi-turn tool calls #24190: [DeepSeek V4] reasoning_content not round-tripped — 400 error on multi-turn tool calls

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

[github-actions]

Thanks for updating the issue! It now includes the error details, environment info, and steps to reproduce. Everything looks good — the compliance flag has been removed.

[igzard]

same here

[mstrYoda]

I faced with the same issue while using OpenCode webui:

The reasoning_content in the thinking mode must be passed back to the API.

[rekram1-node]

If you are using KiloCode this is a bug in Kilo.