`gh aw trial --host-repo=.` fails with "couldn't find remote ref main" when default branch is "master"

[m-titov]

Running  gh aw trial  with  --host-repo=.  in a repository where the default branch is  master  instead of  main  fails immediately, making it impossible to test agentic workflows in such repositories at all.

Steps to reproduce

1. Have a repository with  master  as the default branch
2. Run:

gh aw trial ./dependency-cleanup.md --host-repo=.

Error

✗ failed to install workflow 'dependency-cleanup' in trial mode
  failed to commit and push workflow
  failed to pull latest changes: exit status 1 (output: fatal: couldn't find remote ref main
  )
  exit status 1

Expected behavior

gh aw trial  should respect the repository's actual default branch instead of hardcoding  main .

Actual behavior

The command unconditionally tries to pull from  main , fails, and aborts — no workflow is executed.

Impact

Any organization repository using  master  as the default branch cannot use  gh aw trial --host-repo=.  at all.
This is a complete blocker for local workflow testing.

Suggested fix / workaround

• Fix: detect the repository's default branch dynamically instead of hardcoding  main 
• Workaround: provide a  --branch  flag to let users specify the default branch manually