Agentic Chat (GPT-5 Codex) API
About
Build advanced reasoning agents with Agentic Chat (GPT-5 Codex), 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 (GPT-5 Codex) via the GitLab Duo API with up to 128K output tokens.
Capabilities
Input Modalities
textimage
Output Modalities
text
Reasoning
Yes
Structured Output
Yes
Tool Use
Yes
WeightsClosed
Temperature
Fixed
Attachment
Not Supported
Limits
Context Window
400K
Tokens
Input Limit
272K
Tokens
Max Output
128K
Tokens
Pricing
Standard (per 1M tokens)
Input
Free
Output
Free
Frequently Asked Questions
Agentic Chat (GPT-5 Codex) by GitLab Duo costs Free per 1M input tokens and Free per 1M output tokens.
Model Details
ID
duo-chat-gpt-5-codex
Provider
GitLab DuoFamily
gpt-codex
Release Date
Jan 22, 2026
Knowledge Cutoff
Sep 30, 2024
API Integration