Default model selection

[paddybhoy66]

Describe the feature or problem you'd like to solve

Every time I run copilot cli it defaults to Claude sonnet model. I'd like to be able set my own default model, but can't find an option.

Proposed solution

Provide an option or parameter to set default model.

Example prompts or workflows

No response

Additional context

No response

[rs38]

The only way I found is to shortcut or alias the model specification in the calling command line:
copilot --model gpt-5-mini

[hltdev8642]

ironically I asked copilot how to do this, and it ended up working 😂

Add this to .copilot/config.json :
"default_model": "gpt-5-mini"

(or whatever model you want)

[examon]

This is already supported. You can set a default model using the --model flag, the COPILOT_MODEL environment variable, or the /model slash command, which persists your choice for future sessions. If you believe this isn't resolved, please feel free to reopen this issue.

[datag]

Using /model <model> persists the model to user's config as "model": "<model>", however it seems to be ignored on next application start and is then removed from the config again. So /model (for me) doesn't work to set a persistent default model – it always reverts to Claude Sonnet 4.6 (which has the string (default) after its name).

I tested this with v1.0.23 (reproducible in the last 5 versions) on two different systems (Ubuntu/Linux and MacOS) and two different accounts.

A workaround is setting the mentioned $COPILOT_MODEL environment variable or specifying the CLI option --model (e.g. in an alias).

[stomde]

Great

[mindtricksdev]

Using /model <model> persists the model to user's config as "model": "<model>", however it seems to be ignored on next application start and is then removed from the config again. So /model (for me) doesn't work to set a persistent default model – it always reverts to Claude Sonnet 4.6 (which has the string (default) after its name).

I tested this with v1.0.23 (reproducible in the last 5 versions) on two different systems (Ubuntu/Linux and MacOS) and two different accounts.

A workaround is setting the mentioned $COPILOT_MODEL environment variable or specifying the CLI option --model (e.g. in an alias).

I can confirm this too. /model doesn't persist across CLI restarts.