Claude Fable 5.1 uses Claude bash through Opper on the Messages endpoint, passed through as Anthropic defines it.
Paste this into your coding agent (Claude Code, Cursor, Codex, and more) and it will set up and build with Opper for you.
curl https://api.opper.ai/v3/compat/v1/messages \-H "Authorization: Bearer $OPPER_API_KEY" \-H "Content-Type: application/json" \-d '{"model": "anthropic/claude-fable-5-1", "max_tokens": 1024,"messages": [{"role": "user", "content": "List the files in this repo."}],"tools": [{"type": "bash_20250124", "name": "bash"}]}'
Claude Fable 5.1 runs Claude bash on the routes below.
| Provider | Region | Zero data retention | Training | Input | Output | Cache read |
|---|---|---|---|---|---|---|
| US | No | $10.00 | $50.00 | $0.25$12.50 write | ||
| Multi | No | $10.00 | $50.00 | $0.25$12.50 write |
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.
Step-by-step setup for Claude bash on each of these models through Opper.
Claude drives a desktop through screenshots, clicks and typing in your agent loop.
computer_toolsetClaude reads and edits files with its own file-editing tool.
text_editorGPT models write and run Python in a sandbox, on the Responses endpoint.
code_interpreter