# Anthropic models

Canonical HTML page: [Anthropic models](<https://impossibl.com/anthropic>)
Markdown alternative: [Anthropic models as Markdown](<https://impossibl.com/anthropic.md>)

Access 11 models from Anthropic through the Impossibl API, including Claude Fable 5, Claude Fable 5.1, and Claude Haiku 4.5. Compare API pricing, context windows, and capabilities.

Select two or three models to [compare specifications and API costs](<https://impossibl.com/compare.md>). Model types and billing units are not interchangeable.

## Models

### [Claude Fable 5](<https://impossibl.com/anthropic/claude-fable-5>)

Claude Fable 5 is a text generation model from Anthropic, available through the Impossibl API. Its published context window is 1,000,000 tokens. The advertised input rate is $10.00 per million input tokens. The advertised output rate is $50.00 per million output tokens.

- API identifier: `anthropic/claude-fable-5`
- Creator: Anthropic; model type: Text generation.
- Context window: 1,000,000 tokens; tool calling: Not published.
- Inputs: text, image; outputs: text.
- Base API pricing (USD): $10.00 per million input tokens; $50.00 per million output tokens.
- [Complete model facts, cache rates, context tiers, and FAQs as Markdown](<https://impossibl.com/anthropic/claude-fable-5.md>)

### [Claude Fable 5.1](<https://impossibl.com/anthropic/claude-fable-5-1>)

Claude Fable 5.1 is a text generation model from Anthropic, available through the Impossibl API. Its published context window is 1,000,000 tokens. The advertised input rate is $10.00 per million input tokens. The advertised output rate is $50.00 per million output tokens.

- API identifier: `anthropic/claude-fable-5-1`
- Creator: Anthropic; model type: Text generation.
- Context window: 1,000,000 tokens; tool calling: Not published.
- Inputs: text, image; outputs: text.
- Base API pricing (USD): $10.00 per million input tokens; $50.00 per million output tokens.
- [Complete model facts, cache rates, context tiers, and FAQs as Markdown](<https://impossibl.com/anthropic/claude-fable-5-1.md>)

### [Claude Haiku 4.5](<https://impossibl.com/anthropic/claude-haiku-4-5>)

Claude Haiku 4.5 is a text generation model from Anthropic, available through the Impossibl API. Its published context window is 200,000 tokens. The advertised input rate is $1.00 per million input tokens. The advertised output rate is $5.00 per million output tokens.

- API identifier: `anthropic/claude-haiku-4-5`
- Creator: Anthropic; model type: Text generation.
- Context window: 200,000 tokens; tool calling: Not published.
- Inputs: text, image; outputs: text.
- Base API pricing (USD): $1.00 per million input tokens; $5.00 per million output tokens.
- [Complete model facts, cache rates, context tiers, and FAQs as Markdown](<https://impossibl.com/anthropic/claude-haiku-4-5.md>)

### [Claude Opus 4.5](<https://impossibl.com/anthropic/claude-opus-4-5>)

Claude Opus 4.5 is a text generation model from Anthropic, available through the Impossibl API. Its published context window is 200,000 tokens. The advertised input rate is $5.00 per million input tokens. The advertised output rate is $25.00 per million output tokens.

- API identifier: `anthropic/claude-opus-4-5`
- Creator: Anthropic; model type: Text generation.
- Context window: 200,000 tokens; tool calling: Not published.
- Inputs: text, image; outputs: text.
- Base API pricing (USD): $5.00 per million input tokens; $25.00 per million output tokens.
- [Complete model facts, cache rates, context tiers, and FAQs as Markdown](<https://impossibl.com/anthropic/claude-opus-4-5.md>)

### [Claude Opus 4.6](<https://impossibl.com/anthropic/claude-opus-4-6>)

Claude Opus 4.6 is a text generation model from Anthropic, available through the Impossibl API. Its published context window is 1,000,000 tokens. The advertised input rate is $5.00 per million input tokens. The advertised output rate is $25.00 per million output tokens.

- API identifier: `anthropic/claude-opus-4-6`
- Creator: Anthropic; model type: Text generation.
- Context window: 1,000,000 tokens; tool calling: Not published.
- Inputs: text, image; outputs: text.
- Base API pricing (USD): $5.00 per million input tokens; $25.00 per million output tokens.
- [Complete model facts, cache rates, context tiers, and FAQs as Markdown](<https://impossibl.com/anthropic/claude-opus-4-6.md>)

### [Claude Opus 4.7](<https://impossibl.com/anthropic/claude-opus-4-7>)

Claude Opus 4.7 is a text generation model from Anthropic, available through the Impossibl API. Its published context window is 1,000,000 tokens. The advertised input rate is $5.00 per million input tokens. The advertised output rate is $25.00 per million output tokens.

- API identifier: `anthropic/claude-opus-4-7`
- Creator: Anthropic; model type: Text generation.
- Context window: 1,000,000 tokens; tool calling: Not published.
- Inputs: text, image; outputs: text.
- Base API pricing (USD): $5.00 per million input tokens; $25.00 per million output tokens.
- [Complete model facts, cache rates, context tiers, and FAQs as Markdown](<https://impossibl.com/anthropic/claude-opus-4-7.md>)

### [Claude Opus 4.8](<https://impossibl.com/anthropic/claude-opus-4-8>)

Claude Opus 4.8 is a text generation model from Anthropic, available through the Impossibl API. Its published context window is 1,000,000 tokens. The advertised input rate is $5.00 per million input tokens. The advertised output rate is $25.00 per million output tokens.

- API identifier: `anthropic/claude-opus-4-8`
- Creator: Anthropic; model type: Text generation.
- Context window: 1,000,000 tokens; tool calling: Not published.
- Inputs: text, image; outputs: text.
- Base API pricing (USD): $5.00 per million input tokens; $25.00 per million output tokens.
- [Complete model facts, cache rates, context tiers, and FAQs as Markdown](<https://impossibl.com/anthropic/claude-opus-4-8.md>)

### [Claude Opus 5](<https://impossibl.com/anthropic/claude-opus-5>)

Claude Opus 5 is an Anthropic reasoning model designed for complex software development, extended agent tasks, and professional analysis. It uses adaptive thinking to adjust reasoning effort to the task. Its published context window is 1,000,000 tokens. The advertised input rate is $5.00 per million input tokens. The advertised output rate is $25.00 per million output tokens.

- API identifier: `anthropic/claude-opus-5`
- Creator: Anthropic; model type: Text generation.
- Context window: 1,000,000 tokens; tool calling: Not published.
- Inputs: text, image; outputs: text.
- Base API pricing (USD): $5.00 per million input tokens; $25.00 per million output tokens.
- [Complete model facts, cache rates, context tiers, and FAQs as Markdown](<https://impossibl.com/anthropic/claude-opus-5.md>)

### [Claude Sonnet 4.5](<https://impossibl.com/anthropic/claude-sonnet-4-5>)

Claude Sonnet 4.5 is a text generation model from Anthropic, available through the Impossibl API. Its published context window is 200,000 tokens. The advertised input rate is $3.00 per million input tokens. The advertised output rate is $15.00 per million output tokens.

- API identifier: `anthropic/claude-sonnet-4-5`
- Creator: Anthropic; model type: Text generation.
- Context window: 200,000 tokens; tool calling: Not published.
- Inputs: text, image; outputs: text.
- Base API pricing (USD): $3.00 per million input tokens; $15.00 per million output tokens.
- [Complete model facts, cache rates, context tiers, and FAQs as Markdown](<https://impossibl.com/anthropic/claude-sonnet-4-5.md>)

### [Claude Sonnet 4.6](<https://impossibl.com/anthropic/claude-sonnet-4-6>)

Claude Sonnet 4.6 is an Anthropic model built for coding, computer use, document analysis, and agent planning. It expands on Sonnet 4.5 with improvements in instruction following and reasoning across long inputs. Its published context window is 1,000,000 tokens. The advertised input rate is $3.00 per million input tokens. The advertised output rate is $15.00 per million output tokens.

- API identifier: `anthropic/claude-sonnet-4-6`
- Creator: Anthropic; model type: Text generation.
- Context window: 1,000,000 tokens; tool calling: Not published.
- Inputs: text, image; outputs: text.
- Base API pricing (USD): $3.00 per million input tokens; $15.00 per million output tokens.
- [Complete model facts, cache rates, context tiers, and FAQs as Markdown](<https://impossibl.com/anthropic/claude-sonnet-4-6.md>)

### [Claude Sonnet 5](<https://impossibl.com/anthropic/claude-sonnet-5>)

Claude Sonnet 5 is a text generation model from Anthropic, available through the Impossibl API. Its published context window is 1,000,000 tokens. The advertised input rate is $2.00 per million input tokens. The advertised output rate is $10.00 per million output tokens.

- API identifier: `anthropic/claude-sonnet-5`
- Creator: Anthropic; model type: Text generation.
- Context window: 1,000,000 tokens; tool calling: Not published.
- Inputs: text, image; outputs: text.
- Base API pricing (USD): $2.00 per million input tokens; $10.00 per million output tokens.
- [Complete model facts, cache rates, context tiers, and FAQs as Markdown](<https://impossibl.com/anthropic/claude-sonnet-5.md>)

## Compare Anthropic models

- [Claude Fable 5 vs Claude Fable 5.1](<https://impossibl.com/compare/anthropic/claude-fable-5/anthropic/claude-fable-5-1>); [Markdown comparison](<https://impossibl.com/compare/anthropic/claude-fable-5/anthropic/claude-fable-5-1.md>)
- [Claude Fable 5 vs Claude Haiku 4.5](<https://impossibl.com/compare/anthropic/claude-fable-5/anthropic/claude-haiku-4-5>); [Markdown comparison](<https://impossibl.com/compare/anthropic/claude-fable-5/anthropic/claude-haiku-4-5.md>)
- [Claude Fable 5 vs Claude Opus 4.5](<https://impossibl.com/compare/anthropic/claude-fable-5/anthropic/claude-opus-4-5>); [Markdown comparison](<https://impossibl.com/compare/anthropic/claude-fable-5/anthropic/claude-opus-4-5.md>)
- [Claude Fable 5 vs Claude Opus 4.6](<https://impossibl.com/compare/anthropic/claude-fable-5/anthropic/claude-opus-4-6>); [Markdown comparison](<https://impossibl.com/compare/anthropic/claude-fable-5/anthropic/claude-opus-4-6.md>)
- [Claude Fable 5 vs Claude Opus 4.7](<https://impossibl.com/compare/anthropic/claude-fable-5/anthropic/claude-opus-4-7>); [Markdown comparison](<https://impossibl.com/compare/anthropic/claude-fable-5/anthropic/claude-opus-4-7.md>)
- [Claude Fable 5 vs Claude Opus 4.8](<https://impossibl.com/compare/anthropic/claude-fable-5/anthropic/claude-opus-4-8>); [Markdown comparison](<https://impossibl.com/compare/anthropic/claude-fable-5/anthropic/claude-opus-4-8.md>)

## Frequently asked questions

### Which Anthropic models are available through Impossibl?

The directory lists 11 models from Anthropic available through the Impossibl API, including Claude Fable 5, Claude Fable 5.1, and Claude Haiku 4.5. Open each model page for its API identifier, capabilities, and current pricing.

### How much do Anthropic models cost?

Anthropic model prices vary by model and usage. All rates below are published base API rates in USD. For token-priced models, published input rates start at $1.00 per million input tokens. Published output rates start at $5.00 per million output tokens. Input and output minima may refer to different models. Individual model pages include published cache prices and billing units. Applicable fees and workspace-specific pricing can affect the amount paid.

### What context windows do Anthropic models support?

Among Anthropic models with a published limit on Impossibl, the largest context window is 1,000,000 tokens, listed for Claude Fable 5, Claude Fable 5.1, and Claude Opus 4.6. Context limits vary by model and are separate from maximum output limits.

### What inputs and capabilities do Anthropic models support?

Available model types include text generation. Published input support includes image and text; support varies by model. Tool-calling support is unspecified for 11 models.

### How do I use Anthropic models through an API?

Use the exact model identifier from the model page with the Impossibl API. For example, select anthropic/claude-fable-5 with /v1/chat/completions. Endpoint compatibility depends on the selected model. The API quickstart explains how to create an API key and send a request.

## Sources and related links

Prices, capabilities, limits, and availability describe the public Impossibl API offering. An unpublished fact is unknown; a published zero price is zero. Compare matching billing units and check context tiers before estimating costs.

- [Public Impossibl model catalog](<https://api.impossibl.com/v1/models>)
- [Full model directory as JSON](<https://impossibl.com/models.json>)
- [Model directory as Markdown](<https://impossibl.com/models.md>)
- [API quickstart](<https://impossibl.com/docs/agent-quickstart>)
- [Model documentation](<https://impossibl.com/docs/models>)