Same problem here I have specific branch name patterns and patterns are used within AWS OIDC in order to get deployment permissions.
Would be awesome to have fully customisable PR branch name pattern for copilot (custom prefix, custom separator, etc).

There’s no way to change this right now. The Copilot agent always creates branches with the copilot/ prefix and it’s not configurable, so you can’t swap the / for a - or define your own naming format.

If your pipeline can’t handle slashes, the only workaround at the moment is to rename the branch after Copilot creates it, or update the pipeline to allow / if that’s an option.

I agree though, this would be a great improvement. Being able to customize the branch prefix or use a naming template would make Copilot fit a lot better into existing workflows. Definitely worth raising as a feature request if you haven’t already.

Big +1 as the CI pipeline automatically generates sub-domain deployment with the name of the PR as the sub-domain for testing purposes. It would be great to have the possibility to select between - and / like the dependabot config.

Same here, we need to customize branch names 🙏
Except our issue is not with "/" in the branch name, our process do not allow merging a branch that won't follow a pattern:
<TYPE>/<JIRA-ID>/<DESCRIPTION> where type follows conventional-branch-name.

And yes, absolutely guys, the requirement to provide a JIRA ticket for everything is a huge pain in the ass already

This would at least be partially solved by allowing the model that names the branch to see the copilot-instructions. We can allowlist the copilot/ prefix in our workflow, and add instructions on how to format the rest of the branch name in the custom instructions, but because those instructions are ignored during the branch name run (violating the expectation that they are shown to all models/agents), it's impossible to guide branch naming at all, outside bizarre kludges like prompt injection via code comment.

Currently, GitHub Copilot Agent does not provide a way to customize the branch naming convention—it automatically uses the copilot/ prefix when creating branches. There isn’t an option to replace / with - or to set custom naming templates at this time.

As a workaround, you could:

Manually rename the branch after creation (though this may affect the linked PR).

Use scripts in your deployment pipeline to convert branch names before deploying.

It’s a good idea to submit feedback or a feature request for customizable branch prefixes or naming templates, as this would allow pipelines with stricter naming rules to work seamlessly.

In case it's useful for anyone: for us, having the copilot/ prefix is fine.
We do need at least a ticket number in the branch name, however.

So copilot/ticket-123-short-summary-of-the-task is ok.

I found the following template worked well:

## Guidelines (Must Follow)

- *MAKE SURE* the PR's branch is named **ticket-123-short-summary-of-the-task**
- *MAKE SURE* (...)
- (...) a small limited set of must-follow rules

## Task
(...)

☝️ This seems to work fairly well, assuming the must follow list is not overloaded.
The agent usually ends up doing copilot/ticket-123-short-summary-of-the-task, or might reinterpret the branch name to copilot/ticket-123-agent-generated-branch-name

It is annoying though, and I'd much prefer to be able to select the branch name somewhere in the UI, even if it the copilot/ prefix is fixed.