[Bug]: Claude Code Sonnet 4.6 only gives "API Error: Rate Limit Reached"

[dalyem]

Before submitting

• I searched existing issues and did not find a duplicate.
• I included enough detail to reproduce or investigate the problem.

Area

apps/desktop

Steps to reproduce

I am not sure if there is any steps to reproduce, it appeared out of nowhere, and has now gone on constantly with no workaround to get Sonnet working in app for me.

Expected behavior

The thread should be allowing me to use my Claude Code adapter with the Sonnet model to make changes. I am only getting a Rate Limit error on T3Code, I can use native Claude Code Sonnet and get responses as normal.

Actual behavior

Currently I keep receiving the same error in the screenshot below, across multiple threads using the Claude Code adapter, using Sonnet 4.6, Opus does not seem to be having the same issue. I have tried different things, re-authenticating Claude Code, ensuring everything is up to date, removing and reinstalling Claude Code, waiting 30 minutes and trying again in the same and a new thread, quitting T3Code and reopening. Its odd that this single model is the only one having issues, Codex is working perfectly fine. Opus and Haiku are working fine, just Sonnet is having issues. I have checked the Claude Code status page, and they are not listing any outages, which would track with me being able to use Sonnet in the native Claude Code app.

I did notice right before this, the context tracker of the original thread did not seem to be resetting or accurately tracking the context at least, I am not sure if that has to do with it, I attached a screenshot of the Context tracker in the bottom of this issue.

Screenshot of the Error I am receiving in T3Code: (The response I got in the middle was when I swapped the model to Opus, then I swapped back to Sonnet and it stopped working again)

Provider and T3Code Versions:

My current Claude Usage:

Claude Code working in Native Claude Code App:

Context Tracker:

Impact

Major degradation or frequent failure

Version or commit

No response

Environment

macOS 26.3.1

Logs or stack traces

Screenshots, recordings, or supporting files

No response

Workaround

Use Opus, Haiku, or Codex or use the Claude Code app if you need Sonnet badly.

[lkoehl]

I'm also experiencing this rate limit error, but with both Sonnet and Opus. Haiku is currently the only model that works reliably for me in T3Code.

[ridala]

@juliusmarminge, same issue only Haiku what work

[Sebastian-Neubert]

Same. Haiku 4.5 works but Sonnet 4.6 and Opus 4.6 show "API Error: Rate limit reached" even though there is plenty of usage quota left.

[teagan-thomes]

I'm also having the same issue, all claude models except for haiku return "API Error: Rate limit reached" but work fine in the normal claude code CLI.

[sniperyork]

I'm also having the same issue. CLI works fine but t3 code hits the Rate limit warnings with 2 of the models

[teagan-thomes]

It looks like it has something to do with the app trying to use the 1m context variant even on subs where that wouldn't make sense or be possible. This would also be why haiku works since it doesn't have a 1m option available. You should be able to reproduce this by just using t3code for a bit with any of the lower anthropic subs and just waiting to hit the limit (won't take long)

You can avoid the error by just switching to 200k instead

[dalyem]

I just tested what @teagan-thomes mentioned, and it does seem to be allowing me the ability to use Sonnet again. Let me work for a few hours with this setting and see if the issues reappears.

[juliusmarminge]

#1556