Service/model retirement
Claude API 1M context beta header 200k tokens retired
Requests just above 200k tokens begin failing although the beta header remains present.
Agent Quick Fix
Repair against the current Claude API contract, then keep the change narrow and source-backed.
Product: Claude API
Current-contract area: Retired 1M context beta header no longer expands context
Likely root cause: Requests just above 200k tokens begin failing although the beta header remains present.
Repair direction: Verifier checks migration to the supported successor and preservation of key behavior/data.Symptom
Requests just above 200k tokens begin failing although the beta header remains present.
Why This Happens
The integration is locally correct for a resource that no longer exists or is no longer available to the account; only current service lifecycle data resolves it.
Common Wrong Fixes
- Changing local code without checking the current external contract.
- Retrying the same install, build, or API call with no version/source change.
- Applying a broad unsafe bypass when a narrow compatibility fix is available.
Codex Search Keywords
These are the search terms observed in a neutral Codex validation run for this failure shape.
site:docs.anthropic.com Claude API 1M context beta header 200k tokens retired
site:docs.anthropic.com/en/docs/about-claude/models 1M context beta header Claude Sonnet 4
https://docs.anthropic.com/en/docs/about-claude/models/overview
'1M' in https://docs.anthropic.com/en/docs/build-with-claude/context-windows
"context-1m-2025-08-07"
"1m-token" "anthropic-beta" Claude