Claude Haiku 5.5 on the Anthropic low effort route

[myovchev]

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Summary

The Anthropic AI adapter's low effort route moves from Claude Haiku 4.5 to Haiku 5.5, released 2026-10-07.

• Haiku 5.5 thinks adaptively like the other 5.5 models, so it joins adaptiveModels. The low route sends an explicit medium effort, and structured output on it is no longer forced.
• Haiku 4.5 leaves the model catalog. A project can still configure it explicitly, outside adaptiveModels.
• Smoke suite: the Anthropic token cap leaves room for thinking, and the thinking replay case now fails when the model returns no thinking block to replay.
• The unreleased model-bump changeset now lists Haiku 5.5.

What kind of change does this PR introduce?

• Bug fix
• New feature
• Refactor
• Documentation
• Build-related changes
• Other

Make sure the PR fulfills these requirements:

• It includes a) the existing issue ID being resolved, b) a convincing reason for adding this feature, or c) a clear description of the bug it resolves
• The changelog is updated
• Related documentation has been updated
• Related tests have been updated

If adding a new feature without an already open issue, it's best to open a feature request issue first and wait for approval before working on it.

Other information:

[linear]

PRO-10160