`COPILOT_MODEL=gpt-5 copilot` says it's GPT-4 class

[okuramasafumi]

Describe the bug

❯ COPILOT_MODEL=gpt-5 copilot
 Welcome to GitHub Copilot CLI
 Version 0.0.328 · Commit 3755a93

 Copilot can write, test and debug code right from your terminal. Describe a
 task to get started or enter ? for help. Copilot uses AI, check for mistakes.

 ● Connected to GitHub MCP Server

 ● Logged in with gh as user: okuramasafumi

 ╭─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╮
 │ > What model are you using? │
 ╰─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯

 ● I don’t have access to the exact model identifier. I’m the GitHub Copilot CLI
 assistant (version 0.0.328), powered by an OpenAI GPT-4–class model.

 ╭─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╮
 │ > Aren't you GPT-5? │
 ╰─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯

 ● No. I’m the GitHub Copilot CLI assistant (version 0.0.328), powered by an OpenAI
 GPT‑4–class model. I don’t have the exact internal model ID, but it isn’t GPT‑5.

Affected version

Version 0.0.328 · Commit 3755a93

Steps to reproduce the behavior

COPILOT_MODEL=gpt-5 copilot and ask the model information.

Expected behavior

It's GPT-5.

Additional context

No response

[kud]

Pretty sure it's a typo in the doc and it's actually COPILOT_MODEL=gpt-5

[lostintangent]

Yeah this is just hallucination, since we specifically only support GPT-5 (not 4). I just asked Copilot CLI the same question as OP, and it told me it was using Sonnet 3.5 😄

That said, we should tweak our prompts to make sure the agent knows exactly which model is currently selected 👍🏼

[RyanHecht]

https://github.com/github/copilot-cli/releases/tag/v0.0.329 makes it more clear what model is being used!

[andyfeller]

@okuramasafumi : I'm closing this as a bit stale but also a problem with an older model hallucination. If you have any newer models and CLI versions still impacted, please open a new issue 🙇