1M tokens for Opus 4.6

[Nepomuk5665]

Description

It says: 185,336 19% ($0.00)
When I go over 200k tokens: prompt is too long: 203831 tokens > 200000 maximum
Have tried to turn on:

just tried it with a API key also doesnt allow me to go over 200k tokens.

Found out how to do it! PLEASE add the beta header: betas=["context-1m-2025-08-07"] @fwang

Plugins

OpenCode version

v1.1.52

Steps to reproduce

No response

Screenshot and/or share link

No response

Operating System

MacOS

Terminal

Terminal

[github-actions]

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

• Stuck at "prompt is too long" #8726: Stuck at "prompt is too long" - Reports being stuck with the same "prompt is too long: X tokens > 200000 maximum" error
• [v0.1.158] [Anthropic: Claude Sonnet 4]: AI_APICallError: prompt is too long: 209840 tokens › 200000 maximum #500: [v0.1.158] [Anthropic: Claude Sonnet 4]: AI_APICallError: prompt is too long: 209840 tokens › 200000 maximum - Similar token limit error with Claude model
• prompt is too long #5360: prompt is too long - Another instance of exceeding the 200k token limit
• TOKEN_REFRESH_NEEDED error incorrectly thrown for context overflow (400 prompt too long) #12135: TOKEN_REFRESH_NEEDED error incorrectly thrown for context overflow (400 prompt too long) - Related context overflow handling issue

Feel free to ignore if your specific case differs from these existing issues.

[GeneCodeSavvy]

The context-1m-2025-08-07 beta header is currently only added for Sonnet models (claude-sonnet-*), but Opus 4.6 also supports 1M context per Anthropic's docs (https://docs.anthropic.com/en/docs/build-with-claude/context-windows#1m-token-context-window).

The fix would be to simply extend the check to also match claude-opus-4-6.

per the docs, only Sonnet 4 and Sonnet 4.5, Opus 4.6 supports 1M context, so the condition should be specific imho.

should I open a PR with the fix ? @fwang

[okhsunrog]

Could you test #12342 ? 1M token window works for me with Opus 4.6, at least I went over 300k tokens without any issues

[okhsunrog]

I didn't add context-1m-2025-08-07 header but it still seem to work, can anyone else confirm that? Can you test both with Oauth and Anthropic API?

[ItsWendell]

Just ran into this issue with OAuth Claude Code Max plan on version 1.1.52 @okhsunrog

[okhsunrog]

@ItsWendell are you using my branch? https://github.com/okhsunrog/opencode/tree/feat/opus-4-6-adaptive-thinking
It works for me with Claude Max, OAuth:

you can try adding the header context-1m-2025-08-07 and run it, tell me if it works

[ItsWendell]

@okhsunrog also mentioning here, there's issues when hitting other thresholds, e.g. 400k tokens:

#12342 (comment)

[okhsunrog]

Added more context in #12342 (comment) and #12342 (comment)