Claude Fable 5.1
Anthropic · The frontier tier — deepest reasoning money can buy.
Anthropic's Mythos-class flagship above Opus. Built for problems where being right matters more than being fast or cheap: hard architecture, long-horizon agentic work, high-stakes analysis.
Context window
1M
tokens
Input · $/1M
$10.00
per million tokens
Output · $/1M
$50.00
per million tokens
Vs. cost floor
172×
output cost vs DeepSeek V4.1 Flash
Capability profile
Editorial ratings across six axes (0–100), compiled from publisher reports and public evals — indicative, not measured by TrendNexus.
Benchmark highs
top of field on real-repo bug fixing
graduate-level science reasoning
autonomous terminal task completion
competition mathematics
Where it sits in the field
Output cost per million tokens across all 15 tracked flagships — Claude Fable 5.1 highlighted.
What it's suited to build
Product classes where this model's profile wins — mockups are illustrative, not model output.
Agents
Autonomous engineering agents
Multi-hour refactors, migration campaigns, CI-fixing loops that stay coherent.
Research
Deep research systems
Multi-source synthesis with defensible citations and long-document command.
Product AI
High-stakes copilots
Legal, medical-adjacent and financial workflows where error cost dominates token cost.
Benchmark figures and capability ratings are indicative — compiled from publisher reports and public leaderboards, refreshed editorially, and not independently measured by TrendNexus. Verify against your own evals before procurement decisions. Pricing updates with the daily build.