Repository navigation
Split Bedrock Claude Opus 4.6 into 200K + 1M models and set 1M beta flag #13199
Description
Problem
amazon-bedrock currently treats Claude Opus 4.6 as a single model variant, but the 1M context path on Bedrock requires the experimental context-1m-2025-08-07 beta flag.
Without that flag, requests above the normal 200K window can fail even though the model appears to expose a larger context limit.
Expected behavior
- Default Opus 4.6 model should represent the stable 200K context path.
- A separate explicit 1M variant should be available.
- The 1M variant should automatically send the Bedrock Anthropic beta flag (
anthropicBeta: [\"context-1m-2025-08-07\"]).
Why this helps
- Avoids surprising failures for users on the default model.
- Makes the experimental 1M path opt-in and explicit.
- Matches AI SDK Bedrock guidance for extended context.
Proposed direction
During provider model normalization for amazon-bedrock, detect Opus 4.6 entries and:
- Keep/create a
200Kvariant (no 1M beta flag). - Add a
1M Experimentalvariant with the same Bedrockapi.idplusanthropicBetaset tocontext-1m-2025-08-07.
Happy to open a PR with this behavior.
Metadata
Metadata
Assignees
Labels
No labels
Activity
AndreKurait commentedon Feb 11, 2026
Opened a fix PR for this here: #13200
github-actions commentedon Feb 11, 2026
This issue might be a duplicate or closely related to existing issues. Please check:
context-1m-2025-08-07not sent for Claude Opus 4.6, causing 200k hard limit #12507: Beta headercontext-1m-2025-08-07not sent for Claude Opus 4.6, causing 200k hard limitThese issues all describe the same root cause: the Bedrock provider not sending the required beta flag for Opus 4.6's 1M context window support. It appears work may already be in progress on some of these issues, so please coordinate with the existing discussions before implementing.
karlkurzer commentedon Feb 12, 2026
@AndreKurait I missed your fix
I opened PR #13324 to address this. It's similar to your work, but covers Sonnet 4.5 as well #13200:
fix(provider): split Bedrock 1M context models into explicit 200K and…