How to fix "Unknown API Error: Please contact Roo Code support" in Roo-Code 3.36.x?
In Roo-Code 3.36.x on Windows/VSCode (also reported on Linux), sessions randomly fail with "Unknown API Error: Please contact Roo Code support" and "Empty assistant response" loops that consume tokens, using OpenRouter, RooCloud, or even Claude Code as the provider. The GitHub issue is closed as completed, but users still reported the error through 3.36.14. What causes it and is there a fix or workaround?
Originally asked on GitHub: https://github.com/RooCodeInc/Roo-Code/issues/10106
6 answers
Status: the issue is closed as completed, but the thread contains no confirmation of a fixed release, and users still reported the same error through Roo-Code 3.36.14. The analysis in the thread points to models returning only reasoning content with no assistant text or tool call — for example malformed
<tool_call><function=read_file>...tags in the thinking bubble, seen with Mimo-V2-Flash on OpenRouter, and also while using MCP tools. Roo-Code treats that as an empty assistant response, and the thread's analysis notes that with auto-approval enabled it can retry in a loop and consume tokens.Workarounds that worked for users in the thread:
- Revert to Roo-Code 3.36.6 — one user reported this stops the errors.
- Switch models/provider — one user reported the error stopped after switching from Gemini models back to Claude 4 models via Anthropic with newly generated API keys.
Starting a new chat only recovered the session sometimes; most of the time the error returned and the user had to wait 15–20 minutes. Connecting to Claude Code as the API provider produced the same error, so the problem is not specific to OpenRouter or RooCloud.
One commenter opened PR #10136 to handle models that emit reasoning content but no usable output, mirroring an existing safeguard in the Gemini provider; the thread does not confirm whether it was merged or released.
Did this work for you?What @cett-stephen tried on GitHub (Worked)
Reverted to Roo-Code 3.36.6; the commenter reported that reverting "works ok".
Source: https://github.com/RooCodeInc/Roo-Code/issues/10106#issuecomment-3663328689 (opens external site)
Did this work for you?What @antsbuildit tried on GitHub (Worked)
Switched from Gemini 3 models back to Claude 4 models via Anthropic with newly generated API keys; the commenter reported the error stopped.
Source: https://github.com/RooCodeInc/Roo-Code/issues/10106#issuecomment-3670940201 (opens external site)
Did this work for you?What @uaktags tried on GitHub (Partly worked)
Started a new chat when the error appeared; this sometimes fixed the session, but most of the time the "Empty assistant response" error returned and the user had to wait 15-20 minutes.
Source: https://github.com/RooCodeInc/Roo-Code/issues/10106#issuecomment-3657724207 (opens external site)
Did this work for you?What @manyfranks tried on GitHub (Didn't work)
Connected to Claude Code as the API provider instead of OpenRouter; the same "Unknown API error. Please contact Roo Code support." message appeared.
Source: https://github.com/RooCodeInc/Roo-Code/issues/10106#issuecomment-3658032393 (opens external site)
Did this work for you?What a GitHub user tried on GitHub (Outcome unclear)
A commenter opened PR #10136 to handle models that output reasoning content but no text or tool call, mirroring an existing Gemini provider safeguard; the thread does not confirm whether it was merged or released.
Source: https://github.com/RooCodeInc/Roo-Code/issues/10106#issuecomment-3662101228 (opens external site)
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