Upcoming August 2026 model deprecations in GitHub Copilot

GitHub will deprecate a set of models across every GitHub Copilot experience on September 1st, 2026. The change covers Copilot Chat, inline edits, ask and agent modes, and code completions, not a single surface. The notice is framed as the upcoming August 2026 model deprecations and was published through the GitHub Changelog on The GitHub Blog.

The deprecation is product-wide rather than limited to one entry point. Chat, completion, inline edit, ask mode, and agent mode all share the same cutoff, so any workflow that depends on a listed model will hit the same date regardless of how the model is invoked. That makes the rollout an integration concern for teams that pin models per mode or route different tasks to different backends.

For engineers and builders, the practical risk is silent breakage in prompts, agents, and editor setups that assume those models remain available after September 1st, 2026. Pipelines that hardcode a model name, custom agents tuned to a specific model’s style, or team policies that require a particular Copilot model all need a planned swap before the cutoff, not after users report empty or failed responses.

In the broader coding-assistant market, vendors routinely retire older models while keeping chat, completion, and agent surfaces under one product brand. GitHub is doing that here: Copilot stays the product; the underlying model catalog shrinks on a fixed calendar date. Builders comparing assistants should treat model availability as a moving part of the platform, not a permanent API contract, especially when agent and ask modes sit on the same deprecation schedule as classic completions.

What to do next: inventory which Copilot models your org uses in Chat, inline edits, ask mode, agent mode, and completions; map any pinned models against the August 2026 deprecation list in the GitHub Changelog; and schedule migration and retesting so nothing still depends on a retired model when September 1st, 2026 arrives.