Access GPT-6 Astra and Claude Fable 5.1 for Free via GitLab Duo Agentic Chat Trial

A step-by-step guide to testing Claude Fable 5.1 and GPT-6 Astra through GitLab Ultimate's 30-day free trial with Duo Agentic Chat, including setup steps and cr

tau · September 12, 2026

#GitLab #GitLab Duo #Agentic Chat #Claude Fable 5.1 #GPT-6 Astra #AI Tips

Access GPT-6 Astra and Claude Fable 5.1 for Free via GitLab Duo Agentic Chat Trial

As developers actively seek practical ways to benchmark frontier artificial intelligence models for complex software engineering workflows, tech creator @painn_x shared an accessible workflow to run both Claude Fable 5.1 and GPT-6 Astra for free through GitLab's 30-day Ultimate trial and its built-in Duo Agentic Chat. This method gives developers a direct hands-on testing ground to evaluate agentic code assistance, repository querying, and multi-step reasoning under a 24-credit allocation per user without requiring upfront credit card details.

GitLab Ultimate free trial and GitLab Duo introductory interface

Image source: GitLab

Rather than relying on paid API keys, local model hosting rigs, or complex proxy setups, this approach taps directly into the enterprise-grade AI chat interface provided within the GitLab cloud platform.

GitLab Ultimate Trial and Duo Agentic Chat Model Support

GitLab has been integrating advanced AI capabilities into its DevOps ecosystem, offering Duo Agentic Chat to assist developers with deep repository analysis, automated refactoring suggestions, and multi-step tool-assisted coding tasks.

According to @painn_x, GitLab Duo Agentic Chat currently makes both Anthropic's Claude Fable 5.1 and OpenAI's GPT-6 Astra available directly inside its model selection options, and both can be accessed during the 30-day GitLab Ultimate trial.

  • No Credit Card Requirement: The standard trial sign-up process does not mandate credit card verification upfront, making it straightforward to get started.
  • 24 Free Credits Per User: Each user registered under the trial receives a starter balance of 24 credits, allowing teams to test agentic completions, function calling, and contextual codebase exploration right away.
  • Side-by-Side Flagship Comparison: Developers can switch between GPT-6 Astra and Claude Fable 5.1 within the same agentic chat view to compare code generation fidelity, architectural reasoning, and contextual grasp.

3-Step Setup and Model Selection Walkthrough

The setup workflow shared in the original post is straightforward and takes only a few minutes to complete from start to finish.

  1. Navigate to the Trial Registration Link: Go directly to the official GitLab trial registration page (https://about.gitlab.com/free-trial/, via original shortlink https://t.co/7atHU170BY).
  2. Start the Ultimate Trial: Follow the onboarding prompts to activate your 30-day GitLab Ultimate trial account.
  3. Open Duo Agentic Chat and Choose Your Model: Inside your GitLab workspace, open the Duo Agentic Chat drawer and select either Astra (GPT-6 Astra) or Fable 5.1 (Claude Fable 5.1) from the model picker.

Once chosen, you can immediately begin prompting the selected model to explore your repository, analyze merge requests, explain complex functions, or prototype new logic directly inside GitLab.

24-Credit Allocation and Practical Caveats

While this trial route provides a valuable opportunity to test two of the most capable models available without paying upfront subscription fees, several practical constraints must be taken into account.

  • 24-Credit Allocation Per User: The free credit tier is strictly capped at 24 credits per user. Because agentic operations—such as multi-turn problem solving, autonomous file scanning, and iterative tool calling—consume more tokens and execution units than basic single-turn completions, these credits can deplete rapidly. Plan your testing prompts around specific, focused engineering challenges.
  • Account and Regional Card Verification Checks: Although the baseline onboarding flow does not require credit card entry, individual account trust scores, regional regulations, or atypical IP ranges may trigger additional identity or payment method verifications to guard against automated abuse.
  • Dynamic Trial and Model Availability Policies: Promotional access windows and supported model offerings remain subject to change at GitLab's discretion and model provider agreements. Features and model tiers could be adjusted without prior notice, making it advisable to conduct benchmarks while current terms remain in effect.

Original source