Use Claude web fetch with Claude Fable 5.1

by AnthropicWeb fetch

Claude Fable 5.1 uses Claude web fetch through Opper on the Messages endpoint, passed through as Anthropic defines it. It runs on Anthropic's own route, not on Bedrock or Vertex.

UseClaude web fetchwithin

Add Claude web fetch to Claude Fable 5.1

Set up with agents

Paste this into your coding agent (Claude Code, Cursor, Codex, and more) and it will set up and build with Opper for you.

Get your API key

In your code

1curl https://api.opper.ai/v3/compat/v1/messages \
2  -H "Authorization: Bearer $OPPER_API_KEY" \
3  -H "Content-Type: application/json" \
4  -d '{"model": "anthropic/claude-fable-5-1", "max_tokens": 1024,
5       "messages": [{"role": "user", "content": "Summarise https://opper.ai/pricing"}],
6       "tools": [{"type": "web_fetch_20250910", "name": "web_fetch", "max_uses": 3}]}'

Where you can run it

Claude Fable 5.1 runs Claude web fetch on the routes below.

Provider	Region	Zero data retention	Training	Input	Output	Cache read
Anthropic	US		No	$10.00	$50.00	$0.25$12.50 write

The model

Claude Fable 5.1

by Anthropic

Claude Fable 5.1 is Anthropic's frontier model for agentic coding, knowledge work, and long-running problem solving, with a 1M token context and 128K output.