github / github/copilot-cli

Copilot CLI resume session switches back to default model

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area:models area:sessions
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Description

Describe the bug

bug: Copilot CLI resume session switches automatically back to default model

Affected version

GitHub Copilot CLI 1.0.78.

Steps to reproduce the behavior

Steps to reproduce

  1. Start a session with a specific model:
copilot --yolo --model=gpt-5.6-terra --reasoning-effort=high
  1. Work in the session and exit Copilot CLI.

  2. Resume the session:

copilot --resume <session-id>

or:

copilot --model=gpt-5.6-terra --reasoning-effort=high --resume <session-id>

After finishing loading the session , Copilot CLI silently switches to the default model before any human input.

The conversation context is restored correctly, but the selected model is not preserved.

Expected behavior

The resumed session should continue using gpt-5.6-terra in the begining .

Expected behavior

No response

Additional context

No response

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Reproduce the issue with GitHub Copilot CLI 1.0.78 using the listed --model, --reasoning-effort, and --resume commands. Trace how the resumed session restores its conversation and selected model; done means resuming a session keeps gpt-5.6-terra active before the next human input.

Written by the indexing model from the issue text.

Assessment

Tech stack
shell
Domain
cli
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Quiet
Clarity
Mostly clear
Newbie friendliness
58/100

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