Agentic Chat (Claude Fable 5.1) API
About
Build advanced reasoning agents with Agentic Chat (Claude Fable 5.1), a specialized AI model optimized for complex logic and chain-of-thought tasks. This model delivers available completely free of charge, native tool calling support. Access Agentic Chat (Claude Fable 5.1) via the GitLab Duo API with up to 128K output tokens.
Capabilities
Input Modalities
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Output Modalities
text
Limits
Context Window
1.0M
Tokens
Input Limit
1.0M
Tokens
Max Output
128K
Tokens
Pricing
Standard (per 1M tokens)
Input
Free
Output
Free
Caching (per 1M tokens)
Read
Free
Write
Free
Frequently Asked Questions
Agentic Chat (Claude Fable 5.1) by GitLab Duo costs Free per 1M input tokens and Free per 1M output tokens. Cached reads cost Free per 1M tokens. Cache writes cost Free per 1M tokens.
Model Details
ID
duo-chat-fable-5-1
Provider
GitLab DuoFamily
claude-fable
Release Date
Sep 1, 2026
Knowledge Cutoff
Jun 1, 2026
API Integration