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. Model changes come from the GitLab AI Gateway and take effect regardless of your GitLab version, unless otherwise noted.

For some features, you can select a different model, which persists until you change it.

Default models

Version history

  • Separate model setting for Code Review Flow introduced in GitLab 19.1.
  • Default LLM for Code Review Flow updated to Claude Sonnet 4.6 Vertex on May 20, 2026.
  • Default LLM for Code Review Flow updated to Claude Sonnet 5 Vertex on August 6, 2026.
  • Default LLM for Business Logic Security Scan set to Claude Sonnet 5 Gemini Enterprise Agent Platform on October 2, 2026.
  • Default LLM for Code Review Flow updated to Claude Sonnet 5.5 Gemini Enterprise Agent Platform on October 5, 2026.
  • Separate model setting for Recommend Reviewers Flow introduced in GitLab 19.5.
  • Default LLM for GitLab Duo Agentic Chat, GitLab Duo Developer, and all other agents updated to Claude Sonnet 5.5 Gemini Enterprise Agent Platform on October 7, 2026.
  • Default LLM for Recommend Reviewers Flow updated to Claude Haiku 5.5 Gemini Enterprise Agent Platform on October 8, 2026.

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

Feature Model
GitLab Duo Agentic Chat Claude Sonnet 5.5 Gemini Enterprise Agent Platform
Code Review Flow1 Claude Sonnet 5.5 Gemini Enterprise Agent Platform
Security Review Flow Claude Sonnet 4.6 Gemini Enterprise Agent Platform
Business Logic Security Scan2 Claude Sonnet 5 Gemini Enterprise Agent Platform
Recommend Reviewers Flow Claude Haiku 5.5 Gemini Enterprise Agent Platform
GitLab Duo Developer Claude Sonnet 5.5 Gemini Enterprise Agent Platform
All other agents Claude Sonnet 5.5 Gemini Enterprise Agent Platform

Supported models

Version history

  • GPT-5.2 and GPT-5.3 Codex added as supported models for Code Review Flow on May 26, 2026.
  • Claude Sonnet 5 added as a supported model for Code Review Flow on August 3, 2026.
  • Claude Sonnet 4.5 as a supported model for Code Review Flow deprecated on August 10, 2026 and removed on August 25, 2026.
  • GLM 5.3, Kimi K3, and MiniMax M3 added as supported models for GitLab Duo Agentic Chat and all other agents on September 16, 2026.
  • GPT-6 Sol and GPT-6 Luna added as supported models for GitLab Duo Agentic Chat and all other agents on September 22, 2026.
  • Claude Sonnet 5.5 added as a supported model for GitLab Duo Agentic Chat and all other agents on September 28, 2026.
  • GPT-6.1 Sol added as a supported model for GitLab Duo Agentic Chat and all other agents on September 29, 2026.
  • Claude Sonnet 4.6 and Claude Sonnet 5 added as supported models for Business Logic Security Scan on October 2, 2026.
  • Claude Sonnet 5.5 and Claude Sonnet 5.5 Gemini Enterprise Agent Platform added as supported models for Code Review Flow on October 5, 2026.
  • Claude Haiku 5.5 added as a supported model for GitLab Duo Agentic Chat and all other agents on October 7, 2026.
  • Claude Haiku 5.5 added as a supported model for Recommend Reviewers Flow on October 8, 2026.

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

Model availability can vary by subscription and trial status. For information about model availability during trials, see GitLab Duo Agent Platform trials.

Model GitLab Duo
Agentic Chat		 Code Review Flow3 Security Review Flow Business Logic Security Scan2 Recommend Reviewers Flow All other agents
Claude Fable 54 yes no no no no yes
Claude Fable 5.14 yes no no no no yes
Claude Sonnet 4.5 yes no yes no no yes
Claude Sonnet 4.6 yes yes yes yes no yes
Claude Sonnet 5 yes yes no yes yes yes
Claude Sonnet 5.5 yes yes no no yes yes
Claude Haiku 4.5 yes no no no yes yes
Claude Haiku 5.5 yes no no no yes yes
Claude Opus 4.5 yes no no no no yes
Claude Opus 4.6 yes no no no no yes
Claude Opus 4.7 yes no no no no yes
Claude Opus 4.8 yes no no no no yes
Claude Opus 5 yes no no no no yes
Claude Opus 5.5 yes no no no no yes
Gemini 3.5 Flash yes no no no no yes
Gemini 3.6 Flash yes no no no no yes
Gemini 3.7 Flash yes no no no no yes
Gemini 3.8 Flash yes no no no no yes
GLM 5.3 yes no no no no yes
GPT-5 yes no no no no yes
GPT-5.1 yes no no no no yes
GPT-5.2 yes yes yes no no yes
GPT-5 Codex yes no no no no yes
GPT-5.2 Codex yes no no no no yes
GPT-5.3 Codex yes yes yes no no yes
GPT-5 Mini yes no no no no yes
GPT-5.4 Mini yes no no no no yes
GPT-5.4 Nano yes no no no no yes
GPT-5.54 yes no no no no yes
GPT-5.6 Sol4 yes no no no no yes
GPT-5.6 Terra4 yes no no no no yes
GPT-5.6 Luna4 yes no no no no yes
GPT-6 Astra4 yes no no no no yes
GPT-6 Sol4 yes no no no no yes
GPT-6 Luna4 yes no no no yes yes
GPT-6.1 Sol4 yes no no no no yes
Kimi K3 yes no no no no yes
MiniMax M3 yes no no no no yes

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 setting for Code Review Flow introduced 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.
  • Business Logic Security Scan added to model selection in GitLab 19.5 as an experiment with a flag named bl_security_analyzer. Disabled by default.

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.

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.

Select a model for Agentic Chat

Version history

  • Restricting Agentic Chat to specific models introduced in GitLab 19.1 with a feature flag named model_selection_allowlist. Enabled by default.
  • Restricting Agentic Chat to specific models generally available in GitLab 19.2. Feature flag model_selection_allowlist removed.
  • Restricting Agentic Chat to specific models extended to external agents and third-party tools in GitLab 19.5 with a feature flag named third_party_agent_token_model_allowlist. Disabled by default.

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. Under Model selection, select Manage models.

  4. Go to the GitLab Duo Agentic Chat section.

  5. From the Default model dropdown list, select a model. This model is pinned by default and cannot be changed by users unless you selected the GitLab default model. In that case, all GitLab-managed models are available to users.

  6. Optional. To restrict Agentic Chat to specific models:

    1. Under the Default model dropdown list, select Configure.

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

    3. Select the models you want Agentic Chat to use. To select every model, select the Select all models checkbox. To clear all selected models, select Clear all models.

      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

    To restrict Agentic Chat to specific models, you must select a GitLab-managed model as the default model.

[!flag] The availability of this restriction for external agents and third-party tools is controlled by a feature flag. For more information, see the history.

The restriction also applies to external agents that use GitLab-managed credentials. It also applies to third-party tools, such as OpenCode, that use a GitLab AI Gateway token. If one of these agents or tools requests a model that is not in the list, the request fails with an HTTP 403 error. Add the models that these agents use to the list. Some agents use more than one model. For example, Claude Code also uses a smaller model for background tasks.

Note

A change to the list applies to new tokens. Existing tokens can stay valid for up to one hour.

Select a model for other agentic features

To select a model for other agentic features:

  1. In the top bar, select Search or go to and find your group.
  2. In the left sidebar, select Settings > GitLab Duo.
  3. Under Model selection, select Manage models.
  4. Find the feature you want to configure under GitLab Duo Agent Platform.
  5. Select a model from the dropdown list to set as the default model.
  6. 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.
  7. Optional. To switch all features in a section back to their default models, select Reset to default.

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.

Frontier models are not available during a trial

If you are using a GitLab Duo Agent Platform trial, you cannot use some frontier models because they are not included in trials.

To resolve this, either:

For more information, see GitLab Duo Agent Platform trials.

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.

  1. For GitLab 19.0 or earlier, Code Review Flow uses the default LLM set for GitLab Duo Code Review, the non-agentic version. ↩

  2. Business Logic Security Scan is an experiment. It's available only when the bl_security_analyzer feature flag is enabled and experiment and beta features are turned on. ↩ ↩2

  3. For GitLab 19.0 or earlier, Code Review Flow can only use the models available for GitLab Duo Code Review, the non-agentic version. ↩

  4. This model is subject to limited vendor-side data retention. ↩ ↩2 ↩3 ↩4 ↩5 ↩6 ↩7 ↩8 ↩9 ↩10