Claude Sonnet 4.0 Upgrade

Overview

Anthropic has released their new Sonnet 4.0 model. We need to upgrade all existing Sonnet integrations across GitLab Duo features.

Features to Update

✅ Migration Progress Checklist

Generally Available Features

• GitLab Duo Chat
• Discussion Summary
• Code Suggestions (code generation part)
• Code-based Slash Commands
• Merge Commit Message Generation
• Root Cause Analysis
• Vulnerability Resolution
• Vulnerability Explanation
• Code Review

Beta Features

• Merge Request Summary
• GitLab Duo Workflow: Claude Sonnet 4 for Workflow (#545193 - closed)

Experimental Features

• Code Review Summary
• Agentic Chat

Required Changes

• Add model configuration file for model flexibility
• New prompt definition created to use the Claude 4.0 model.
• Feature flag created to slow rollout of correct prompt version

Technical Details

• Model name changes required as per Anthropic documentation
• Affects both GitLab.com and self-managed instances

Implementation Steps

1. Update model configurations in each feature
2. Update unit_primitives.yml by adding the new model to every feature that will adopt it
3. Verify performance improvements
4. Deploy updates
5. Update documentation
6. Update AI catalog - https://duo-feature-list-754252.gitlab.io/

Timeline

Priority: ASAP

References

• Anthropic Announcement
• Model Documentation
• GitLab Duo Documentation
• Model Migration docs
• LiteLLM Model Support Issue

Proposed Solution

1. Create a new model config_claude_4
2. Ensure that there nothing new about the model that requires changes to our API schema references
3. Simultaneous ensure Quota usage for prod accounts are setup for rollout
4. Engage feature teams to create new prompt definitions. We can utilize the .update_script I wrote in the AI gateway for teams to bump the version.

GitLab Duo Feature Status Table

GitLab Duo Feature Status Table

As of June 17, 2025

Feature	Current Status	Timeline	ETA	Issue
Duo Chat	✅	Enabling the Duo ReAct Agent feature flag for internal users June 3rd All Duo Chat tools enabled Jun 10th	Jun 6th	#545491 (closed)
Code Generation	✅	Feature flag enabled globally - 2025-06-16.	June 17th	#545489 (closed)
Code-based Slash Commands	✅	Feature flag enabled globally - 2025-06-16.	June 17th	#545490 (closed)
Merge Request Summary	✅	Feature flag enabled globally - 2025-06-18	June 18th	#545504 (closed)
Duo Code Review	MRs created: Rails and AIGW	Likely waiting until after Duo Code Review GA to enable FF. Do not want to impact the GA timeline.	18.2	#545502 (closed)
Code Review Summary	✅	Feature flag enabled globally - 2025-06-18	June 18th	https://gitlab.com/gitlab-org/gitlab/-/issues/545693
Merge Commit Message Generation	✅	Feature flag enabled globally - 2025-06-18	June 18th	#545695 (closed)
Explain Vulnerability				#545697
Vulnerability Resolution	Planning	Requires quality test suite run by groupstatic analysis. Currently looking at 18.3 #545117 (comment 2531634454)		#545698
Root Cause Analysis	✅	Feature flag enabled globally - 2025-07-01	%18.2	#545699 (closed)
Duo Workflow	✅	Feature flag enabled globally - 2025-06-12	2025/06/12	#545700 (closed)