Code with Claude Fable 5
in AdaL
Anthropic's most capable generally available model brings Mythos-class capability to everyday agentic work. Use claude-fable-5 in AdaL for long-horizon software engineering, knowledge work, vision, and research.
Get StartedRun /model and pick Claude Fable 5 from the New category · $10/M input · $50/M output tokens
Why use Fable 5 in AdaL
A frontier upgrade for developers who need stronger long-session reasoning, multimodal context, and safer high-capability execution
Built for long-horizon engineering
Anthropic positions Claude Fable 5 as its most capable generally available model for extended software engineering work, migrations, debugging, and agentic coding.
Mythos-class capability, generally available
Fable 5 brings Mythos-class reasoning into the Claude API and consumption-based plans, while Claude Mythos 5 remains restricted to trusted access programs.
Strong vision and knowledge work
Use it in AdaL for repo-aware coding, research synthesis, visual inputs, dense documents, and other high-context analysis tasks.
Research-ready reasoning
Anthropic highlights stronger performance across knowledge work and scientific research, making it a strong choice for hard investigation loops in AdaL.
Safeguarded fallback behavior
For cybersecurity, biology, chemistry, or distillation-sensitive requests, Fable safeguards may route to Claude Opus 4.8 instead of failing abruptly.
$10/M input · $50/M output
Claude Fable 5 is priced at $10/M input tokens and $50/M output tokens, with claude-fable-5 as the API model id.
How to pick Claude Fable 5
Available in AdaL CLI and Desktop through the model selector
Open AdaL CLI or AdaL Desktop
Use the coding environment where AdaL already understands your repo, tools, and task context.
Run /model
Open the model selector and choose Claude Fable 5 from the New category.
Start a long-horizon task
Ask AdaL to inspect, plan, edit, test, and review with Claude Fable 5 powering the agent loop.
What to know before you switch
Selected details from Anthropic's Claude Fable 5 launch announcement
"Claude Fable 5 is designed for state-of-the-art long-horizon software engineering, knowledge work, vision, and research."
Anthropic
"Pick Fable 5 when you want AdaL to reason deeply across a large codebase, plan carefully, edit surgically, and verify the result."
AdaL
"Fallback to Claude Opus 4.8 is an intentional safeguard path for sensitive cyber, bio, chemistry, and distillation topics."
Safety profile
"Claude Fable 5 is the generally available model for AdaL users; Claude Mythos 5 remains restricted to trusted access."
Availability
Source: Anthropic launch announcement for Claude Fable 5 and Claude Mythos 5.
Ready to try Fable 5 in AdaL?
Open AdaL CLI or Desktop, run /model, and choose Claude Fable 5 from the new category.
Get Started with AdaL