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

Version history

  • Default LLM for Code Review Flow updated to Claude Sonnet 4.6 Gemini Enterprise Agent Platform in GitLab 19.1.
  • Default LLM for Code Review Flow updated to Claude Sonnet 5 Gemini Enterprise Agent Platform in GitLab 19.3.

This table lists the default model for each feature in the Agent Platform.

Feature Model
GitLab Duo Agentic Chat Claude Sonnet 4.6 Gemini Enterprise Agent Platform
Code Review Flow Claude Sonnet 5 Gemini Enterprise Agent Platform
Security Review Flow Claude Sonnet 4.6 Gemini Enterprise Agent Platform
All other agents Claude Sonnet 4.6 Gemini Enterprise Agent Platform

Supported models

Version history

  • GPT-5.2 and GPT-5.3 Codex added as supported models for Code Review Flow in GitLab 19.1.
  • Claude Sonnet 5 added as a supported model for Code Review Flow in GitLab 19.3.

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

Model GitLab Duo
Agentic Chat		 Code Review Flow Security Review Flow All other agents
Claude Fable 5 1 yes no no yes
Claude Sonnet 4.5 yes yes 2 yes yes
Claude Sonnet 4.6 yes yes yes yes
Claude Sonnet 5 yes yes no yes
Claude Haiku 4.5 yes no no yes
Claude Opus 4.5 yes no no yes
Claude Opus 4.6 yes no no yes
Claude Opus 4.7 yes no no yes
Claude Opus 4.8 yes no no yes
Claude Opus 5 yes no no yes
Gemini 3.5 Flash yes no no yes
Gemini 3.6 Flash yes no no yes
Gemini 3.7 Flash yes no no yes
GPT-5 yes no no yes
GPT-5.1 yes no no yes
GPT-5.2 yes yes yes yes
GPT-5 Codex yes no no yes
GPT-5.2 Codex yes no no yes
GPT-5.3 Codex yes yes yes yes
GPT-5 Mini yes no no yes
GPT-5.4 Mini yes no no yes
GPT-5.4 Nano yes no no yes
GPT-5.5 1 yes no no yes
GPT-5.6 Sol 1 yes no no yes
GPT-5.6 Terra 1 yes no no yes
GPT-5.6 Luna 1 yes no no yes

Footnotes:

  1. This model is subject to limited vendor-side data retention.
  2. Support for Claude Sonnet 4.5 with Code Review Flow was deprecated in GitLab 19.3 and is planned for removal in 19.4.

Select a model for a feature

  • Offering: GitLab.com

Version history

  • 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.
  • Separate model selection from GitLab Duo Code Review introduced for Code Review Flow in GitLab 19.1, using the Agentic Code Review setting.
  • Ability to restrict GitLab Duo Agentic Chat to specific models added in GitLab 19.1.
  • Security Review Flow added to model selection in GitLab 19.2.

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:

  1. In the top bar, select Search or go to and find your group.

  2. In the left sidebar, select Settings > GitLab Duo.

  3. Select Manage models.

  4. Go to the GitLab Duo Agentic Chat section.

  5. Select a model from the dropdown list to set as the default model.

  6. Optional. To restrict what other models users can select for Agentic Chat:

    1. Under Available models, select Configure.

    2. In the Available models: Agentic Chat dialog, select the Restrict to specific models checkbox.

    3. Select the models that you want Agentic Chat to be able to use. To select every model, select the Select all models checkbox. When every model is selected, select Clear all models to clear the selection.

      Note

      The default model is always available to users and cannot be cleared. To save your changes, you must select at least one model in addition to the default model.

    4. Select Save.

    Note

    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:

  1. In the top bar, select Search or go to and find your group.
  2. In the left sidebar, 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 to set as the default model.
  6. 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:

  1. Select Claude Haiku 4.5 or GPT-5.4 Mini.
  2. Test your use case thoroughly.
  3. Evaluate if performance meets your requirements.
  4. 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:

  1. Check that the connection type for your IDE is set to WebSocket.
  2. Ask your network administrator to make sure WebSocket traffic to your GitLab instance is allowed.