docs: remove non-existent -b agent-skills from example

[Copilot]

The README example used -b agent-skills with adobe/helix-website, but this branch doesn't exist, causing clone failures.

Change:

• Removed -b agent-skills flag from example command in README.md

# Before
upskill adobe/helix-website -b agent-skills

# After
upskill adobe/helix-website

The command now uses the default branch, which works correctly.

Original prompt

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This section details on the original issue you should resolve

<issue_title>Fail to Add Skills</issue_title>
<issue_description># Error Report: gh upskill Branch Not Found

Summary

The gh upskill command fails when attempting to clone the adobe/helix-website repository with a non-existent branch agent-skills.

Error Details

Command

gh upskill adobe/helix-website -b agent-skills

Error Output

Created temp dir: /var/folders/w5/_vhbt15n00x9qm05b70pl56h0000gn/T/tmp.F0URMMAxO2
Cloning adobe/helix-website (branch: agent-skills) ...
Cloning into '/var/folders/w5/_vhbt15n00x9qm05b70pl56h0000gn/T/tmp.F0URMMAxO2/src'...
fatal: Remote branch agent-skills not found in upstream origin
failed to run git: exit status 128

Environment Information

• Operating System: macOS (based on temp directory path)
• Command: gh upskill
• Repository: adobe/helix-website
• Branch: agent-skills (non-existent)

Steps to Reproduce

1. Run command: gh upskill adobe/helix-website -b agent-skills
2. Observe the git clone failure with exit status 128

Expected Behavior

The command should successfully clone the repository using the specified branch and complete the upskill process.

Actual Behavior

The command fails during the git clone operation because the branch agent-skills does not exist in the remote repository.

Root Cause

The branch agent-skills does not exist in the adobe/helix-website repository. This was confirmed by the git error message: "fatal: Remote branch agent-skills not found in upstream origin"

Suggested Solutions

For Users

1. Use default branch: Run without the -b flag

   gh upskill adobe/helix-website

2. Find available branches: List all branches to find the correct one

   gh api repos/adobe/helix-website/branches --paginate --jq '.[].name'

3. Check documentation: Verify if the branch name has changed or if you're referencing outdated documentation

For gh upskill Maintainers

1. Improve error handling: Catch the git clone failure and provide a more user-friendly error message
2. Add branch validation: Check if the branch exists before attempting to clone
3. Suggest alternatives: When a branch is not found, list available branches or suggest using the default

Additional Notes

• The error occurs during the git clone phase, specifically when git tries to checkout a non-existent branch
• The temporary directory is created successfully before the failure
• Exit status 128 is a generic git error code often associated with fatal errors

Reproduction Rate

100% - This error occurs consistently when attempting to use a non-existent branch

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Report generated on: November 4, 2025</issue_description>

<agent_instructions>Update the docs to leave out the -b agent-skills from the example comments</agent_instructions>

Comments on the Issue (you are @copilot in this section)

@trieloff @ddttom use it without the -b agent-skills branch. @trieloff We need to update the docs

• Fixes Fail to Add Skills #8

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