choosing-a-model changedabout-claude/models/choosing-a-model
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5656**Claude Opus 5.5** (`claude-opus-5-5`) is built for long-running agentic coding and knowledge work, with [adaptive thinking](https://platform.claude.com/docs/en/build-with-claude/thinking) always on. If your integration forces tool use (`tool_choice` of type `any` or `tool`), turns thinking off, or uses the `computer_20251124` computer use tool, see [Breaking changes](https://platform.claude.com/docs/en/models/opus-5-5/whats-new-opus-5-5#breaking-changes) before switching.
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58**Claude Fable 5.2** (`claude-fable-5-2`) is Anthropic’s most capable model open to all customers. It’s built for demanding reasoning and long-horizon agentic work. **Claude Mythos 5.2** (`claude-mythos-5-2`) offers the same capabilities only to organizations verified through Anthropic’s verification programs, such as the [Cyber Verification Program](https://support.claude.com/en/articles/14604842). Both models use always-on [adaptive thinking](https://platform.claude.com/docs/en/build-with-claude/thinking). If your code edits earlier turns of a conversation, moves a conversation between models, uses the `computer_20251124` computer use tool, or uses the advisor tool, see [Claude Fable 5.2 breaking changes](https://platform.claude.com/docs/en/models/fable-5-2/whats-new-fable-5-2#breaking-changes) before switching.
58**Claude Fable 5.2** (`claude-fable-5-2`) is Anthropic’s most capable model open to all customers. It’s built for demanding reasoning and long-horizon agentic work. **Claude Mythos 5.2** (`claude-mythos-5-2`) offers the same capabilities only to organizations verified through Anthropic’s verification programs, such as the [Cyber Verification Program](https://support.claude.com/en/articles/14604842). Both models use always-on [adaptive thinking](https://platform.claude.com/docs/en/build-with-claude/thinking). If your code changes `system`, `tools`, or earlier messages in a conversation, moves a conversation between models, uses the `computer_20251124` computer use tool, or uses the advisor tool, see [Claude Fable 5.2 breaking changes](https://platform.claude.com/docs/en/models/fable-5-2/whats-new-fable-5-2#breaking-changes) before switching.
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6060For context windows, output limits, and prices, see the [model comparison table](https://platform.claude.com/docs/en/models/overview#latest-models-comparison).
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