Claude Fable 5.1 as a coding agent in your terminal

Strengths

A newer, premium-priced Claude model. Worth trying on the hardest tasks; compare it with Opus on your own code using /derby.

OpenRouter's description:

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...

Use Claude Fable 5.1 as a coding agent in your terminal

Start Darce in your project with Claude Fable 5.1:

npm install -g darce-cli
darce --model anthropic/claude-fable-5.1

Already in a session? Type /model anthropic/claude-fable-5.1, or open the picker with Ctrl+P. Darce then reads your code, edits files and runs commands with Claude Fable 5.1; risky commands ask first, and /undo reverses any change, including what shell commands did. No account yet? npx darce-cli lets you try it free. Which plan includes which models is on the pricing page.

Make it your default or a gear

In ~/.darcerc, set it as the starting model or add it to the gears you move between with Shift+↑ / Shift+↓ (see configuration):

{
  "router": { "default": "anthropic/claude-fable-5.1" },
  "gears": ["qwen/qwen3-coder", "anthropic/claude-fable-5.1"]
}

Compare it on your own code

Benchmarks rarely match your repository. Race Claude Fable 5.1 against two other models on a real task and keep the best diff:

/derby --models anthropic/claude-fable-5.1,anthropic/claude-opus-5.5,anthropic/claude-sonnet-5.5 fix the failing test

Read more about /derby and /swarm.

Related models

• Claude Opus 5.5 (Anthropic): 1M tokens, $4.00 / $20.00 per 1M tokens
• Claude Sonnet 5.5 (Anthropic): 1M tokens, $2.00 / $10.00 per 1M tokens
• Claude Haiku 5.5 (Anthropic): 1M tokens, $0.10 / $0.50 per 1M tokens
• Claude Opus 5 (Anthropic): 1M tokens, $5.00 / $25.00 per 1M tokens
• GPT-6 Sol (OpenAI): 1.05M tokens, $2.00 / $10.00 per 1M tokens
• GPT-6 Astra (OpenAI): 1.05M tokens, $10.00 / $50.00 per 1M tokens
• GPT-5.5 (OpenAI): 1.05M tokens, $5.00 / $30.00 per 1M tokens
• Qwen3.8 Max (0902) (Qwen (Alibaba)): 1M tokens, $2.00 / $6.00 per 1M tokens

All models · Getting started · Claude Code alternative

Model data from OpenRouter, refreshed daily. Prices are OpenRouter's list rates and show relative cost; your Darce allowance is used in proportion to them.