Guide
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How to Use Claude Fable 5 for Free via GitLab Duo (30-Day Trial)

4 min read

Anthropic dropped Claude Fable 5 recently. It's their Mythos-class model, built for long-running agentic coding tasks. And you can use it for free. GitLab bundles it into their Duo Agent Platform through a 30-day Ultimate trial. No credit card. I set it up in about five minutes. Here's how.

1 Create a GitLab Account

  1. Go to gitlab.com
  2. Hit Sign In. You can use Google, GitHub, or your email
  3. If you pick GitHub, it'll ask you to authorize the GitLab app. Just click allow
  4. Check your inbox for a verification code and enter it

2 Set Up Your Project

  1. For your role, pick Software Developer. It doesn't matter much
  2. Select "I want to explore GitLab"
  3. Click Create a New Project, then Just Me
  4. Name it whatever you want (I used test-project). Leave the README box checked. Hit Create Project

3 Activate the Free Trial

  1. On your project dashboard, look for the Start a Free Trial banner. It's usually in the top-right
  2. It asks for a company name and country. The company name can be anything
  3. Click Activate My Free Trial. No credit card, no payment info

4 Select Claude Fable 5

  1. Find the GitLab Duo Chat icon. It's a chat bubble, usually bottom-left or in the right toolbar
  2. At the bottom of the chat panel there's a model dropdown. Click it
  3. Search for Claude Fable 5 – Anthropic and select it
  4. Send a quick "hello" to confirm it's working. You should get a response right away

📺 Prefer Watching? Here's a Walkthrough

This video was made by another creator, not me. Sharing it because it covers the same setup.