Agent Platform AI models
- Tier: Premium, Ultimate
- Offering: GitLab.com, GitLab Self-Managed, GitLab Dedicated
Every GitLab Duo feature uses a default model. GitLab might update default models to optimize performance. For some features, you can select a different model, which persists until you change it.
Default models
This table lists the default model for each feature in the Agent Platform.
| Feature | Model |
|---|---|
| GitLab Duo Agentic Chat | Claude Sonnet 4.6 Vertex |
| Code Review Flow | Claude Sonnet 4.6 Vertex |
| All other agents | Claude Sonnet 4.6 Vertex |
Supported models
This table lists the models you can select for features in the Agent Platform.
| Model | GitLab Duo Agentic Chat | Code Review Flow | All other agents |
|---|---|---|---|
| Claude Fable 5 1 | No | ||
| Claude Sonnet 4.5 | |||
| Claude Sonnet 4.6 | |||
| Claude Haiku 4.5 | No | ||
| Claude Opus 4.5 | No | ||
| Claude Opus 4.6 | No | ||
| Claude Opus 4.7 | No | ||
| Claude Opus 4.8 | No | ||
| Gemini 3.5 Flash | No | ||
| GPT-5 | No | ||
| GPT-5.1 | No | ||
| GPT-5.2 | |||
| GPT-5.5 1 | No | ||
| GPT-5 Codex | No | ||
| GPT-5.2 Codex | No | ||
| GPT-5.3 Codex | |||
| GPT-5 Mini | No | ||
| GPT-5.4 Mini | No | ||
| GPT-5.4 Nano | No |
Footnotes:
- This model is subject to limited vendor-side data retention.
Select a model for a feature
- Offering: GitLab.com
You can select a model to be the default model for a feature in a top-level group. The model that you select applies to that feature for all child groups and projects.
Prerequisites:
- You have the Owner role for the group.
- The group that you select models for is a top-level group.
- In GitLab 18.3 or later, if you belong to multiple GitLab Duo namespaces, you must assign a default namespace.
Select a model for Agentic Chat
To select a model for Agentic Chat:
In the top bar, select Search or go to and find your group.
In the left sidebar, select Settings > GitLab Duo.
Select Configure features.
Go to the GitLab Duo Agentic Chat section.
Select a model from the dropdown list to set as the default model.
Optional. To restrict what other models users can select for Agentic Chat:
- Under Available models, select Configure.
- In the Available models: Agentic Chat dialog, select the Restrict to specific models checkbox.
- Select the models that you want Agentic Chat to be able to use.
- Select Save.
If you do not restrict Agentic Chat to specific models, users can choose from all GitLab-managed models.
Select a model for a non-Agentic Chat feature
To select a model for a non-Agentic Chat feature:
- In the top bar, select Search or go to and find your group.
- In the left sidebar, select Settings > GitLab Duo.
- Select Configure features.
- Go to the GitLab Duo Agent Platform section.
- Select a model from the dropdown list to set as the default model.
- Optional. To apply the model to all features in the section, select Apply to all.
To specify a model for the GitLab Duo CLI, see select a model.
Selecting the right model
For many use cases, starting with a faster, more cost-effective model like Claude Haiku 4.5 or GPT-5.4 Mini can be the optimal approach. For this approach:
- Select Claude Haiku 4.5 or GPT-5.4 Mini.
- Test your use case thoroughly.
- Evaluate if performance meets your requirements.
- Upgrade only if necessary for specific capability gaps.
You can use this approach for the following:
- Exploratory or high-volume tasks
- Applications with strict latency requirements
- Cost-sensitive implementations
Troubleshooting
When selecting models other than the default, you might encounter the following issues.
Model is not available
If you are using the default GitLab model for a GitLab Duo AI-native feature, GitLab might change the default model without notifying the user to maintain optimal performance and reliability.
If you have selected a specific model for a GitLab Duo AI-native feature, and that model is not available, there is no automatic fallback. The feature that uses this model is unavailable.
No default GitLab Duo namespace
When using a GitLab Duo feature with a selected model, you might get an error that indicates that you need to set a default GitLab Duo namespace.
This issue occurs when you belong to multiple GitLab Duo namespaces or work on a project locally that does not have a GitLab remote configured.
To resolve this, set a default GitLab Duo namespace.
Model selection for Agentic Chat in IDEs does not work
When selecting a model for Agentic Chat in your IDE, you might find that model selection does not work.
To resolve this:
- Check that the connection type for your IDE is set to WebSocket.
- Ask your network administrator to make sure WebSocket traffic to your GitLab instance is allowed.