Agent Platform AI models

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• Tier: Premium, Ultimate
• Offering: GitLab.com, GitLab Self-Managed, GitLab Dedicated

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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 4.5 Vertex

Supported models

This table lists the models you can select for features in the Agent Platform.

Model	GitLab Duo Agentic Chat	All other agents
Claude Sonnet 4	{{< yes >}}	{{< yes >}}
Claude Sonnet 4 Vertex	{{< yes >}}	{{< yes >}}
Claude Sonnet 4.5	{{< yes >}}	{{< yes >}}
Claude Sonnet 4.5 Vertex	{{< yes >}}	{{< yes >}}
Claude Sonnet 4.6	{{< yes >}}	{{< yes >}}
Claude Haiku 4.5	{{< yes >}}	{{< yes >}}
Claude Opus 4.5	{{< yes >}}	{{< yes >}}
Claude Opus 4.6	{{< yes >}}	{{< yes >}}
GPT-5	{{< yes >}}	{{< yes >}}
GPT-5 Codex	{{< yes >}}	{{< yes >}}
GPT-5.2 Codex	{{< yes >}}	{{< yes >}}
GPT-5.3 Codex	{{< yes >}}	{{< yes >}}
GPT-5 Mini	{{< yes >}}	{{< yes >}}
GPT-5.2	{{< yes >}}	{{< yes >}}

Select a model for a feature

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• Offering: GitLab.com

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• Introduced for top-level groups in GitLab 18.1 with a flag named ai_model_switching. Disabled by default.
• Changed to beta in GitLab 18.4.
• Enabled in GitLab 18.4.
• Introduced model selection for GitLab Duo Agent Platform in GitLab 18.4 with a flag called duo_agent_platform_model_selection. Disabled by default.
• Generally available in GitLab 18.5. Feature flag ai_model_switching enabled.
• Feature flag duo_agent_platform_model_selection enabled in GitLab 18.6.
• Feature flag ai_model_switching removed in GitLab 18.7.
• Feature flag duo_agent_platform_model_selection removed in GitLab 18.9.

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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.

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:

1. In the top bar, select Search or go to and find your group.
2. Select Settings > GitLab Duo.
3. Select Configure features.
4. Go to the GitLab Duo Agent Platform section.
5. Select a model from the dropdown list.
6. Optional. To apply the model to all features in the section, select Apply to all.

In the IDE, model selection for GitLab Duo Agentic Chat is applied only when the connection type is set to WebSocket.

To specify a model for the GitLab Duo CLI, see select a model.

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 states that you have not selected a default GitLab Duo namespace. For example, on:

• GitLab Duo Code Suggestions, you might get Error 422: I'm sorry, you have not selected a default GitLab Duo namespace. Please go to GitLab and in user Preferences - Behavior, select a default namespace for GitLab Duo.
• GitLab Duo Chat, you might get Error G3002: I'm sorry, you have not selected a default GitLab Duo namespace. Please go to GitLab and in user Preferences - Behavior, select a default namespace for GitLab Duo.

This issue occurs when you belong to multiple GitLab Duo namespaces, but have not chosen one as your default namespace.

To resolve this, set a default GitLab Duo namespace.