Sweep 22 Sep 2026 · 17:19Z Build v2.1.280 501 read Stable v2.1.267 Latest v2.1.280 Next v2.1.280 Feeds RSS JSON llms.txt Unofficial
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Agent SDK reference - Python changed

agent-sdk/python

Nearest release: v2.1.280, published under an hour before upstream edited the page. Shown because the two are within 24 hours of each other. Nothing here says the release caused the edit.

Upstream edited this page at 22 Sep 2026 16:28 UTC, give or take a minute or two: the time comes from Anthropic’s own sitemap rather than from a commit. This site recorded the change at 22 Sep 2026 16:37 UTC.

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First seen 14 Aug 2026 this site's first read of the page
Recorded edits28to this page, all time

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13451345Use with the `betas` field in `ClaudeAgentOptions` to enable beta features.
13461346 
13471347<Warning>
1348 The `context-1m-2025-08-07` beta is retired as of April 30, 2026. Passing this header with Claude Sonnet 4.5 or Sonnet 4 has no effect, and requests that exceed the standard 200k-token context window return an error. To use a 1M-token context window, migrate to [Claude Opus 5, Claude Sonnet 5, Claude Sonnet 4.6, Claude Opus 4.6, Claude Opus 4.7, or Claude Opus 4.8](https://platform.claude.com/docs/en/about-claude/models/overview), which include 1M context at standard pricing with no beta header required.
1348 The `context-1m-2025-08-07` beta is retired as of April 30, 2026. Passing this header with Claude Sonnet 4.5 or Sonnet 4 has no effect, and requests that exceed the standard 200k-token context window return an error. To use a 1M-token context window, migrate to [Claude Opus 5.5, Claude Opus 5, Claude Sonnet 5, Claude Sonnet 4.6, Claude Opus 4.6, Claude Opus 4.7, or Claude Opus 4.8](https://platform.claude.com/docs/en/about-claude/models/overview), which include 1M context at standard pricing with no beta header required.
13491349</Warning>
13501350 
13511351### `McpSdkServerConfig`