Agent Breaking Changes_

← OpenCode

OpenCode v1.18.27

2026-09-02 · official notes

Summary

• Default provider header timeouts to five minutes so slow model startups fail less often.
• Default streamed chunk timeouts to five minutes, with false supported to disable them.
• Let Anthropic thinking.blockBinding opt out via config when you need to keep the provider default. (@dkindlund)

Full notes

## Core

### Bugfixes

- Default provider header timeouts to five minutes so slow model startups fail less often.
- Default streamed chunk timeouts to five minutes, with `false` supported to disable them.
- Let Anthropic `thinking.blockBinding` opt out via config when you need to keep the provider default. (@dkindlund)
- Limit Anthropic thinking block binding to Claude 5.1+ models so older deployments do not reject requests.
- Avoid unhandled errors when canceling timed-out SSE reads. (@AlexanderWillner)

**Thank you to 2 community contributors:**
- @AlexanderWillner:
  - fix(provider): handle SSE reader cancel rejections (#44944)
- @dkindlund:
  - fix(opencode): let config opt out of Anthropic thinking blockBinding (#46820)