Models overview changedmodels/overview
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2323## Compare models
2424
25If you're unsure which model to use, start with [Claude Opus 5.5](https://platform.claude.com/docs/en/models/opus-5-5/overview) for most workloads. Use [Claude Fable 5.1](https://platform.claude.com/docs/en/models/fable-5-1/overview) for demanding reasoning and long-horizon agentic work, or when your evals on Claude Opus 5.5 at higher effort still fall short. All current models support text and image input, text output, multilingual capabilities, vision, and tool use. Each model's page lists the platforms it's available on.
25If you’re unsure which model to use, start with [Claude Opus 5.5](https://platform.claude.com/docs/en/models/opus-5-5/overview) for most workloads. Use [Claude Fable 5.1](https://platform.claude.com/docs/en/models/fable-5-1/overview) for demanding reasoning and long-horizon agentic work, or when your evals on Claude Opus 5.5 at higher effort still fall short. All current models support text and image input, text output, multilingual capabilities, vision, and tool use. Each model’s page lists the platforms it’s available on.
2626
2727| Feature | Claude Fable 5.1 | Claude Opus 5.5 | Claude Sonnet 5.5 | Claude Haiku 5.5 |
2828| :------------------------------------------------------------------------------------------------------------------------------------------------------------ | :-------------------------------------------------------------------------------- | :------------------------------------------------------------------------------ | :---------------------------------------------------------------------------------- | :--------------------------------------------------------------------------------------- |
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6565Legacy models (still available): [Claude Fable 5](https://platform.claude.com/docs/en/models/fable-5/overview), [Claude Opus 5](https://platform.claude.com/docs/en/models/opus-5/overview), [Claude Opus 4.8](https://platform.claude.com/docs/en/models/opus-4-8/overview), [Claude Opus 4.7](https://platform.claude.com/docs/en/models/opus-4-7/overview), [Claude Opus 4.6](https://platform.claude.com/docs/en/models/opus-4-6/overview), [Claude Opus 4.5](https://platform.claude.com/docs/en/models/opus-4-5/overview), [Claude Sonnet 5](https://platform.claude.com/docs/en/models/sonnet-5/overview), [Claude Sonnet 4.6](https://platform.claude.com/docs/en/models/sonnet-4-6/overview), [Claude Haiku 4.5](https://platform.claude.com/docs/en/models/haiku-4-5/overview).
6666
67Once you've picked a model, [learn how to make your first API call](https://platform.claude.com/docs/en/get-started). To understand how model IDs, aliases, and snapshots work, see [Model IDs and versioning](https://platform.claude.com/docs/en/about-claude/models/model-ids-and-versions); for the reliable-knowledge and training-data cutoffs behind each model, see Anthropic's [Transparency Hub](https://www.anthropic.com/transparency).
67Once you’ve picked a model, [learn how to make your first API call](https://platform.claude.com/docs/en/get-started). To understand how model IDs, aliases, and snapshots work, see [Model IDs and versioning](https://platform.claude.com/docs/en/about-claude/models/model-ids-and-versions); for the reliable-knowledge and training-data cutoffs behind each model, see Anthropic’s [Transparency Hub](https://www.anthropic.com/transparency).
6868
6969## Using the Models API
7070
71You can query model capabilities and token limits programmatically with the [Models API](https://platform.claude.com/docs/en/api/models/list). The response includes `max_input_tokens`, `max_tokens`, and a `capabilities` object for every available model.
71You can query model capabilities and token limits programmatically with the [Models API](https://platform.claude.com/docs/en/api/models/list). The response includes [`max_input_tokens`](https://platform.claude.com/docs/en/api/models#model_info.max_input_tokens), [`max_tokens`](https://platform.claude.com/docs/en/api/models#model_info.max_tokens), and a [`capabilities`](https://platform.claude.com/docs/en/api/models#model_info.capabilities) object for every available model.
7272
73Each model in the response also has a `line` field, which names the model line it belongs to. Claude Opus 4.5 and Claude Opus 4.6 both report `opus`. Use `line` to group models, for example, in a model picker. `line` is `null` when a model belongs to no line. Read `line` instead of inferring it from the model's `id`. Anthropic might add more lines, so don't treat the set of values as fixed.
73Each model in the response also has a [`line`](https://platform.claude.com/docs/en/api/models#model_info.line) field, which names the model line it belongs to. Claude Opus 4.5 and Claude Opus 4.6 both report `opus`. Use `line` to group models, for example, in a model picker. `line` is `null` when a model belongs to no line. Read `line` instead of inferring it from the model’s `id`. Anthropic might add more lines, so don’t treat the set of values as fixed.
7474
75Each model's `capabilities` object includes `thinking.types.disabled`, which reports whether the model accepts `thinking: {type: "disabled"}`, the setting that [turns thinking off](https://platform.claude.com/docs/en/build-with-claude/thinking#turning-thinking-off). `supported` is `false` when the model rejects `"disabled"` with a 400 error, and `true` on a model that doesn't support thinking. Even when `supported` is `true`, the API can still reject a `"disabled"` request for another reason. One such reason is an [effort](https://platform.claude.com/docs/en/build-with-claude/effort) level that the model doesn't allow with thinking off.
75Each model’s `capabilities` object includes [`thinking.types.disabled`](https://platform.claude.com/docs/en/api/models#thinking_types.disabled), which reports whether the model accepts `thinking: {type: "disabled"}`, the setting that [turns thinking off](https://platform.claude.com/docs/en/build-with-claude/thinking#turning-thinking-off). `supported` is `false` when the model rejects `"disabled"` with a 400 error, and `true` on a model that doesn’t support thinking. Even when `supported` is `true`, the API can still reject a `"disabled"` request for another reason. One such reason is an [effort](https://platform.claude.com/docs/en/build-with-claude/effort) level that the model doesn’t allow with thinking off.
7676
77Each model's `capabilities` object also includes `thinking.types.between_tools`, which reports whether the model accepts `thinking: {type: "between_tools"}`, the setting that [turns off up-front thinking](https://platform.claude.com/docs/en/build-with-claude/thinking#turning-thinking-off). `supported` is `false` when the model rejects `"between_tools"` with a 400 error. Even when `supported` is `true`, the API can still reject a `"between_tools"` request for another reason, such as an [effort](https://platform.claude.com/docs/en/build-with-claude/effort) level that the model doesn't allow with `"between_tools"`. For Claude Sonnet 5.5, for example, the Models API reports `thinking.types.between_tools.supported` as `true` and `thinking.types.disabled.supported` as `false`.
77Each model’s `capabilities` object also includes [`thinking.types.between_tools`](https://platform.claude.com/docs/en/api/models#thinking_types.between_tools), which reports whether the model accepts `thinking: {type: "between_tools"}`, the setting that [turns off up-front thinking](https://platform.claude.com/docs/en/build-with-claude/thinking#turning-thinking-off). `supported` is `false` when the model rejects `"between_tools"` with a 400 error. Even when `supported` is `true`, the API can still reject a `"between_tools"` request for another reason, such as an [effort](https://platform.claude.com/docs/en/build-with-claude/effort) level that the model doesn’t allow with `"between_tools"`. For Claude Sonnet 5.5, for example, the Models API reports `thinking.types.between_tools.supported` as `true` and `thinking.types.disabled.supported` as `false`.
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79Each model's `capabilities` object also includes `server_tools`, which reports whether the model accepts the [web search](https://platform.claude.com/docs/en/agents-and-tools/tool-use/web-search-tool) and [code execution](https://platform.claude.com/docs/en/agents-and-tools/tool-use/code-execution-tool) tools. It doesn't cover other server tools, such as web fetch. `server_tools.web_search.supported` and `server_tools.code_execution.supported` are `true` when the model accepts at least one version of that tool, not necessarily every version. `server_tools.supported` is `true` when the model accepts at least one of the two tools. Even when a tool is supported, your organization's settings can still cause a request that uses it to fail. For example, an administrator can [disable web search](https://platform.claude.com/docs/en/agents-and-tools/tool-use/web-search-tool#how-to-use-web-search).
79Each model’s `capabilities` object also includes [`server_tools`](https://platform.claude.com/docs/en/api/models#model_capabilities.server_tools), which reports whether the model accepts the [web search](https://platform.claude.com/docs/en/agents-and-tools/tool-use/web-search-tool) and [code execution](https://platform.claude.com/docs/en/agents-and-tools/tool-use/code-execution-tool) tools. It doesn’t cover other server tools, such as web fetch. `server_tools.web_search.supported` and `server_tools.code_execution.supported` are `true` when the model accepts at least one version of that tool, not necessarily every version. `server_tools.supported` is `true` when the model accepts at least one of the two tools. Even when a tool is supported, your organization’s settings can still cause a request that uses it to fail. For example, an administrator can [disable web search](https://platform.claude.com/docs/en/agents-and-tools/tool-use/web-search-tool#how-to-use-web-search).
8080
81The top-level `code_execution` capability is a different check. It reports whether code that Claude runs in the code execution tool can call the request's other tools, as in [programmatic tool calling](https://platform.claude.com/docs/en/agents-and-tools/tool-use/programmatic-tool-calling). For Claude Haiku 4.5, for example, the Models API reports `server_tools.code_execution.supported` as `true` and `code_execution.supported` as `false`.
81The top-level [`code_execution`](https://platform.claude.com/docs/en/api/models#model_capabilities.code_execution) capability is a different check. It reports whether code that Claude runs in the code execution tool can call the request’s other tools, as in [programmatic tool calling](https://platform.claude.com/docs/en/agents-and-tools/tool-use/programmatic-tool-calling). For Claude Haiku 4.5, for example, the Models API reports `server_tools.code_execution.supported` as `true` and `code_execution.supported` as `false`.
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83The API reference lists the List Models endpoint’s parameters and full response.
84
85(See the `models/list` method in [the API reference](https://platform.claude.com/docs/en/api/models/list).)
86
8387## Prompt and output performance
8488
8589Current Claude models excel in:
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8791* **Performance:** Top-tier results in reasoning, coding, multilingual tasks, long-context handling, honesty, and image processing. See [Prompting best practices](https://platform.claude.com/docs/en/build-with-claude/prompt-engineering/claude-prompting-best-practices) for general and model-specific prompting guidance.
8892* **Engaging responses:** Claude models are ideal for applications that require rich, human-like interactions. If you prefer more concise responses, adjust your prompts to guide the model toward the output length you want. Refer to the [prompt engineering guides](https://platform.claude.com/docs/en/build-with-claude/prompt-engineering) for details.
89* **Output quality:** When migrating from a previous model generation, you might notice larger improvements in overall performance. If you're on Claude Opus 5 or earlier, see the [Claude Opus 5.5 migration guide](https://platform.claude.com/docs/en/models/opus-5-5/migration-guide).
93* **Output quality:** When migrating from a previous model generation, you might notice larger improvements in overall performance. If you’re on Claude Opus 5 or earlier, see the [Claude Opus 5.5 migration guide](https://platform.claude.com/docs/en/models/opus-5-5/migration-guide).
9094
9195## Get started with Claude
9296
93Whether you're a developer looking to integrate Claude into your applications or a user wanting to experience the power of AI firsthand, the following resources can help.
97Whether you’re a developer looking to integrate Claude into your applications or a user wanting to experience the power of AI firsthand, the following resources can help.
9498
9599<CardGroup cols={3}>
96100 <Card title="Intro to Claude" icon="check" href="https://platform.claude.com/docs/en/intro">
97 Explore Claude's capabilities and development flow.
101 Explore Claude’s capabilities and development flow.
98102 </Card>
99103
100104 <Card title="Quickstart" icon="lightning" href="https://platform.claude.com/docs/en/get-started">
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