Claude Opus 5 (Fast)

Fast-mode variant of [Opus 5](/anthropic/claude-opus-5) - identical capabilities with higher output speed at 2x pricing relative to regular Opus 5. Learn more in Anthropic's docs: https://platform.claude.com/docs/en/build-with-claude/fast-mode

ChatAnthropic1M tokens$10.9006 / $54.503 · 1M

anthropic/claude-opus-5-fast

Context
1M tokens
Completion cap
128,000
Tools
Yes
JSON
Yes
Released
2026-07-24

Call it from Geek Hub

Same OpenAI SDK. Change the base URL and the model id.

curl https://api.geekhub.mx/v1/chat/completions \
  -H "Authorization: Bearer $GEEKHUB_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "anthropic/claude-opus-5-fast",
    "messages": [{"role": "user", "content": "Hola"}]
  }'
Get an API key

Frequently asked questions

What is Claude Opus 5 (Fast)?
Fast-mode variant of [Opus 5](/anthropic/claude-opus-5) - identical capabilities with higher output speed at 2x pricing relative to regular Opus 5. Learn more in Anthropic's docs: https://platform.claude.com/docs/en/build-with-claude/fast-mode Claude Opus 5 (Fast) runs on the Geek Hub API (OpenAI-compatible). Model id: anthropic/claude-opus-5-fast.
Is Claude Opus 5 (Fast) free?
No. Input is $10.9006 per 1M tokens and output is $54.503 per 1M tokens on Geek Hub (markup included).
What is the context length of Claude Opus 5 (Fast)?
Claude Opus 5 (Fast) has a 1M tokens context window. It supports up to 128,000 completion tokens.
Does Claude Opus 5 (Fast) support tool calling and structured outputs?
Claude Opus 5 (Fast) accepts tools and tool_choice for function calling. It also supports structured outputs via a JSON schema in response_format.
When was Claude Opus 5 (Fast) released?
Claude Opus 5 (Fast) was released on 2026-07-24.

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