GitLab Duo AI models
- Tier: Premium, Ultimate
- Add-on: GitLab Duo Core, Pro, or Enterprise
- Offering: GitLab.com, GitLab Self-Managed, GitLab Dedicated
Every GitLab Duo feature uses a default model. GitLab might update default models to optimize performance. Model changes come from the GitLab AI Gateway and take effect regardless of your GitLab version.
You can select a different model for a feature, which persists until you change it.
Default models
The following table lists the default model for each GitLab Duo feature.
| Feature | Model |
|---|---|
| Code Suggestions | |
| Code Generation | Claude Sonnet 4.6 Gemini Enterprise Agent Platform |
| Code Completion | Codestral 25.08 Fireworks |
| GitLab Duo Chat | |
| General Chat | Claude Sonnet 4.6 Gemini Enterprise Agent Platform |
| Code Explanation | Claude Sonnet 4.6 Gemini Enterprise Agent Platform |
| Test Generation | Claude Sonnet 4.6 Gemini Enterprise Agent Platform |
| Refactor Code | Claude Sonnet 4.6 Gemini Enterprise Agent Platform |
| Fix Code | Claude Sonnet 4.6 Gemini Enterprise Agent Platform |
| Root Cause Analysis | Claude Sonnet 4.6 Gemini Enterprise Agent Platform |
| GitLab Duo for merge requests | |
| Merge Commit Message Generation | Claude Sonnet 4.6 Gemini Enterprise Agent Platform |
| Merge Request Summary | Claude Sonnet 4.6 Gemini Enterprise Agent Platform |
| Code Review Summary | Claude Sonnet 4.6 Gemini Enterprise Agent Platform |
| Non-Agentic Code Review | Claude Sonnet 4.5 Gemini Enterprise Agent Platform |
| Other GitLab Duo features | |
| Vulnerability Explanation | Claude Sonnet 4.6 Gemini Enterprise Agent Platform |
| Vulnerability Resolution | Claude Sonnet 4.6 Gemini Enterprise Agent Platform |
| Discussion Summary | Claude Sonnet 4.6 Gemini Enterprise Agent Platform |
| GitLab Duo for CLI | Claude Sonnet 4.6 Gemini Enterprise Agent Platform |
Supported models
The following tables list the models you can select for each feature.
Code Suggestions
| Model | Code Generation | Code Completion |
|---|---|---|
| Claude Sonnet 4.5 | ||
| Codestral 25.01 Fireworks | No | |
| Codestral 25.08 Fireworks | No | |
| Codestral 25.08 Gemini Enterprise Agent Platform | No | |
| Gemini 2.5 Flash Gemini Enterprise Agent Platform | No |
GitLab Duo Non-Agentic Chat
| Model | General Chat | Code Explanation | Test Generation | Refactor Code | Fix Code | Root Cause Analysis |
|---|---|---|---|---|---|---|
| Claude Haiku 4.5 | No | No | ||||
| Claude Sonnet 3 | No | No | ||||
| Claude Sonnet 4.5 | ||||||
| Claude Sonnet 4.5 Gemini Enterprise Agent Platform | ||||||
| Claude Sonnet 4.6 | ||||||
| Claude Sonnet 4.6 Gemini Enterprise Agent Platform |
GitLab Duo for merge requests
| Model | Merge Commit Message Generation | Merge Request Summary | Code Review Summary | Non-Agentic Code Review |
|---|---|---|---|---|
| Claude Sonnet 4.5 | ||||
| Claude Sonnet 4.5 Gemini Enterprise Agent Platform | No | No | No | |
| Claude Sonnet 4.6 | No | No | No | |
| Claude Sonnet 4.6 Gemini Enterprise Agent Platform | No | No | No |
Other GitLab Duo features
| Model | Vulnerability Explanation | Vulnerability Resolution | GitLab Duo for CLI | Discussion Summary |
|---|---|---|---|---|
| Claude Haiku 4.5 | No | No | ||
| Claude Sonnet 4.5 | ||||
| Claude Sonnet 4.5 Gemini Enterprise Agent Platform | ||||
| Claude Sonnet 4.6 | ||||
| Claude Sonnet 4.6 Gemini Enterprise Agent Platform |
Select a model for a feature
- Offering: GitLab.com
You can select a model for a feature in a top-level group. The model that you select applies to that feature for all child groups and projects.
To set a model for an instance on GitLab Self-Managed or GitLab Dedicated, see model selection.
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.
To select a model for a feature:
- In the top bar, select Search or go to and find your group.
- In the left sidebar, select Settings > GitLab Duo.
- Under Model selection, select Manage models.
- Find the feature you want to configure and select a model from the dropdown list.
- Optional. To apply a model to multiple features in a section, from the Bulk update dropdown list, select a model. The model applies only to the features it is compatible with.
- Optional. To switch all features in a section back to their default models, select Reset to default.
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 to maintain optimal performance and reliability, without notifying you.
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.