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Microsoft Delays VS Code May 2025 Release; Pushes Ahead on Copilot Chat Open Sourcing
Normally right now we'd be reporting on the May 2025 edition of Visual Studio Code, perhaps detailing the work to take GitHub Copilot Chat open source.
However, Microsoft has extended the development cycle for the May 2025 release by one week, while working to integrate AI functionality more deeply into the open source Code - OSS core.
The delay and AI integration efforts were disclosed in GitHub project planning documents and a recent company blog post. Microsoft said the Copilot Chat extension would be released under the MIT license, with relevant components to follow in the core Code - OSS base. However, the GitHub Copilot backend services will remain closed source.
Targeting an 'Open Source AI Editor '
Microsoft is positioning the move as part of its open-source goals, saying, "This is the next and logical step for us in making VS Code an open source AI editor."
While the Code - OSS base is already available under the MIT license, Microsoft's official VS Code distribution includes proprietary elements such as branding, telemetry, and integrations with Microsoft services. That distinction remains unchanged. "Visual Studio Code is 'built' on open source, rather than 'is' open source," Microsoft clarified in an accompanying FAQ.
Scope of the Open Source Effort
The company's current focus is on the GitHub Copilot Chat extension, which provides AI-powered chat functionality inside VS Code. The extension will be released under the MIT license, and Microsoft plans to refactor relevant components into the Code - OSS core over time.
"We'll first open-source the GitHub Copilot Chat extension," Microsoft explained in its GitHub issue tracking the initiative #249031. "Once open source, we re-evaluate how we split the functionality between VS Code Core, built-in extension(s), and the Chat extension."
Key elements of the open-sourcing process include conducting a compliance review of the codebase, defining service access strategies, and developing test infrastructure to handle the inherent variability of AI model responses. Microsoft will also move the Chat extension client code to a new public repository.
Microsoft noted that the Copilot backend services, which power features such as model serving and semantic search, will remain proprietary and are not part of the open-sourcing effot.
Microsoft listed the reasons for the open sourcing:
- Large language models have significantly improved, mitigating the need for "secret sauce" prompting strategies.
- The most popular and effective UX treatments for AI interactions are now common across editors. We want to enable the community to refine and build on these common UI elements by making them available in a stable, open codebase.
- An ecosystem of open source AI tools and VS Code extensions has emerged. We want to make it easier for these extension authors to build, debug, and test their extensions. This is especially challenging today without access to the source code in the Copilot Chat extension.
- We've gotten a lot of questions about the data that is collected by AI editors. Open sourcing the Copilot Chat extension enables you to see the data we collect, increasing transparency.
- Malicious actors are increasingly targeting AI developer tools. Throughout VS Code's history as OSS, community issues and PRs have helped us find and fix security issues quickly.
Architecture and API Changes
The VS Code team is also using the initiative to streamline how AI functionality is structured in the editor. Currently, next edit suggestions (NES) and chat functionality are implemented in the Copilot Chat extension, while code completions are handled by a separate GitHub Copilot Completions extension. Microsoft said it plans to unify NES and completions within the Chat extension. The company added that it does not have concrete plans to open source the Completions extension at this time.
For extension developers, Microsoft said it will maintain backwards compatibility for stable APIs. "You should not expect any impact on your extension," the company stated.
Release Delay
The Copilot Chat open-sourcing initiative is a key work item in Microsoft's Iteration Plan for May 2025. On May 21, Microsoft extended the iteration by one week. The plan now lists the "Endgame done" date as June 6, 2025.
No official reason was provided for the extension. However, the Copilot Chat open-sourcing work is marked as a "work in progress" priority item in the iteration plan, and GitHub discussions around issue #249031 reflect active community feedback and architectural decisions in progress, which may have contributed to the scheduling change.
Next Steps
Microsoft expects to implement the changes over the next couple of months, with a stated goal of enabling external contributions to VS Code's AI features alongside contributions to the broader Code - OSS project. Contributors will be able to run and test AI features using Code - OSS, though either licensed access to Microsoft's GitHub Copilot service or alternative model access will be required to fully exercise the functionality.
About the Author
David Ramel is an editor and writer at Converge 360.