Agent-Skills.md

Agent Skills: GitHub Issue Images

Fetch and inspect screenshots embedded in GitHub issues or pull requests, especially `github.com/user-attachments/assets/...` URLs that often return `404` without GitHub authentication. Use when an issue or PR includes images and an agent needs the actual pixels from CLI or tmux.

UncategorizedID: uuta/dotfiles/github-issue-images

Repository

uuta/dotfiles
uuta
12

Install this agent skill to your local

pnpm dlx add-skill https://github.com/uuta/dotfiles/tree/HEAD/skills/github-issue-images

Skill Files

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skills/github-issue-images/SKILL.md

Skill Metadata

Name
github-issue-images
Description
Fetch and inspect screenshots embedded in GitHub issues or pull requests, especially `github.com/user-attachments/assets/...` URLs that often return `404` without GitHub authentication. Use when an issue or PR includes images and an agent needs the actual pixels from CLI or tmux.

GitHub Issue Images

Goal

Read GitHub-hosted screenshots reliably from CLI.

The main failure mode this skill covers is:

  • issue or PR text is readable with gh
  • embedded screenshot URLs use github.com/user-attachments/assets/...
  • plain curl returns 404
  • the image is actually downloadable when the request uses gh auth token

Do not declare the screenshot unavailable until the authenticated path has failed.

Use When

  • a GitHub issue or PR includes screenshots or mock images
  • direct fetch of a user-attachments URL fails
  • a tmux agent needs the image locally for visual review

Do not use when:

  • the image is already attached in the current chat thread
  • the asset is a normal public URL that downloads without GitHub auth
  • the task does not need the actual image content

Procedure

1. Read the issue or PR text

Examples:

gh issue view 120 --repo uuta/trander-flutter
gh pr view 119 --repo uuta/trander-flutter --comments

2. Extract attachment URLs

Search for GitHub issue attachment URLs from the raw body, not the rendered terminal view:

gh issue view 120 --repo uuta/trander-flutter --json body --jq '.body' | \
  rg -o 'https://github\.com/user-attachments/assets/[A-Za-z0-9-]+'

For PR comments:

gh pr view 119 --repo uuta/trander-flutter --json body,comments \
  --jq '.body, (.comments[].body // empty)' | \
  rg -o 'https://github\.com/user-attachments/assets/[A-Za-z0-9-]+'

3. Download with GitHub auth

Use the bundled script:

scripts/download-github-attachment.sh \
  --url 'https://github.com/user-attachments/assets/<id>' \
  --output /tmp/issue-120-ideal.png

This script uses:

gh auth token

and sends:

Authorization: Bearer <token>

to the attachment URL before following redirects.

4. Verify the file

Recommended checks:

file /tmp/issue-120-ideal.png
ls -lh /tmp/issue-120-ideal.png

If you need to inspect the pixels in-session, use view_image on the saved file path.

5. Only then report a blocker

If download still fails:

  • check gh auth status
  • confirm the URL is a github.com/user-attachments/assets/... link
  • retry once with the script
  • only then say the screenshot is unavailable

Naming Convention

When an issue includes multiple images, prefer explicit filenames:

  • /tmp/issue-120-actual.png
  • /tmp/issue-120-ideal.png
  • /tmp/pr-119-review-1.png

This makes later review prompts less ambiguous.

Notes

  • 404 from unauthenticated curl is not conclusive for GitHub issue attachments.
  • Prefer --json body or --json body,comments when extracting URLs. The rendered gh issue view output may wrap text and make extraction brittle.
  • Prefer this skill before asking the user to re-upload a screenshot.
  • Keep the image-fetch step separate from implementation. This skill is about access and inspection, not UI coding.