Measured on Composite
This model has not carried enough traffic on Composite yet to publish a success rate, a latency figure or a traffic rank. The numbers appear here once it has.
AI model
Anthropic: Claude Sonnet 5 (fast) (Reasoning)
anthropic/claude-sonnet-5:fast-reasoning
Anthropic: Claude Sonnet 5 (fast) (Reasoning) is a 1,000,000-token model served on Composite at $2.50 per million tokens in and $12.5 per million tokens out.
Try in PlaygroundSpecifications
| Model ID | anthropic/claude-sonnet-5:fast-reasoning |
|---|---|
| Provider | Claude Platform on AWS |
| Context window | 1,000,000 tokens |
| Accepts | text, image, file |
| Returns | text |
| Input price | $2.50 per million tokens |
| Output price | $12.5 per million tokens |
| Prompt caching | Supported — cached input is billed at the provider's cache rate, on credits and plans alike |
| Web search | $0.0125 per result |
| Thinking | Optional - see "Anthropic: Claude Sonnet 5 (fast) (Reasoning) (Reasoning)" in the catalog to turn it on by default |
| Moderated | Yes - by the provider |
| Cost on a monthly plan | About 26 plan credits per typical call (8k in, 1k out) |
| Routing endpoints | 1 |
Pricing
$2.50 per million tokens input · $12.5 per million tokens output
Credits pay the provider’s price plus 25%; cache hits cost less.
On a monthly plan, a typical call (8k tokens in, 1k out) uses about 26 plan credits, at the provider's own price.
Provider
Claude Platform on AWS
Roleplay fit
Claude models are widely regarded for nuanced, in-character writing and for following detailed system prompts and character cards closely.
Context behavior
With a 1,000,000-token context window, it can hold a long-running roleplay or a full lorebook in memory without losing earlier plot details, so it suits multi-session campaigns and character cards with heavy backstory.
Cost for regular use
It sits in the mid-range on price, a reasonable pick for regular roleplay use without going for the cheapest option available.
From the provider
Sonnet 5 is Anthropic's most capable Sonnet-class model, with frontier performance across coding, agents, and professional work. It supports adaptive thinking with selectable reasoning effort levels (low, medium, high, max,...
Supplied by Claude Platform on AWS, not written by Composite.
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