free-ai-api-keys

anthropic/claude-fable-5.1

Anthropic: Claude Fable 5.1

Context length
1000K
Input / 1M tokens
$10.00
Output / 1M tokens
$50.00
Released
2026-09-01
Modality
text+image+file->text

About Anthropic: Claude Fable 5.1

Claude Fable 5.1 improves on Claude Fable 5 across the board, with the biggest gains in agentic coding, long-running agentic workflows, and knowledge work: long code refactors, front-end and visual...

Call Anthropic: Claude Fable 5.1

Via OpenRouter: one base URL for every provider.

curl https://openrouter.ai/api/v1/chat/completions \
  -H "Authorization: Bearer $OPENROUTER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "anthropic/claude-fable-5.1",
    "messages": [{"role": "user", "content": "Say hello"}]
  }'

Direct on Anthropic:

curl https://api.anthropic.com/chat/completions \
  -H "Authorization: Bearer $ANTHROPIC_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-fable-5.1",
    "messages": [{"role": "user", "content": "Say hello"}]
  }'

Anthropic keys

OpenRouter keys

OpenRouter keys work for anthropic/claude-fable-5.1 regardless of the upstream provider.