Diffity Diff
Launch the diffity browser diff viewer for the current repo so you can inspect working tree, ref, or GitHub PR changes before review or fixes.
Overview
diffity-diff is an agent skill most often used in Ship review (also Build integrations) that starts the diffity browser viewer for a repo’s working tree, git ref, or GitHub PR.
Install
npx skills add https://github.com/kamranahmedse/diffity --skill diffity-diffWhat is this skill?
- User-invocable skill opens diffity in the browser via CLI with optional git ref or GitHub PR URL
- Reuses an existing per-repo server or starts a new one; background via agent Bash tool not shell &
- Post-start flow: diffity list --json for port, then share localhost URL with the user
- Documented handoffs to /diffity-resolve (comments) and /diffity-review (AI review)
- Auto-install path: npm install -g diffity when which diffity fails
- Post-start wait of 2 seconds before diffity list --json
- Optional ref forms include main..feature, HEAD~3, and GitHub pull URLs
Adoption & trust: 718 installs on skills.sh; 687 GitHub stars; 3/3 security scanners passed (skills.sh audits).
What problem does it solve?
You cannot quickly see or annotate your changes in a browser diff UI before review or comment resolution.
Who is it for?
Solo developers using Claude Code or similar agents who want a reusable local diff session per repo with optional PR deep links.
Skip if: CI-only teams that forbid local servers or agents without permission to run global npm installs and background processes.
When should I use this skill?
User invokes /diffity-diff or asks to open the diffity diff viewer; optional ref argument for git range or GitHub PR.
What do I get? / Deliverables
diffity runs in the background with a stable localhost URL so you can comment in-browser, then invoke diffity-resolve or diffity-review as next steps.
- Running diffity instance URL (e.g. http://localhost:5391)
- Background diff session reusable for resolve or AI review follow-ups
Recommended Skills
Journey fit
Spans multiple journey phases - primary shelf plus alternate fits below.
Opening a structured diff viewer is a pre-merge review action, so Ship/review is the canonical shelf even when used mid-build. The skill exists to visualize and annotate diffs—core code review workflow—not launch marketing or infra monitoring.
Where it fits
Open diffity against main..feature to annotate issues before merge.
Paste a GitHub PR URL so diffity loads the same change set locally for agent-assisted review.
Compare HEAD~3 after integrating a dependency bump to verify only expected files moved.
How it compares
Local browser diff orchestration—not a substitute for git diff in scripts or hosted GitHub PR review alone.
Common Questions / FAQ
Who is diffity-diff for?
Indie builders and agent users who already use diffity and want the agent to start or reuse the viewer and return a clean localhost link.
When should I use diffity-diff?
In Ship review before merging; during Build when comparing feature branches; anytime you need HEAD~n, main..branch, or a GitHub PR URL visualized in diffity.
Is diffity-diff safe to install?
The skill runs a local server and may npm install -g diffity; review the Security Audits panel on this Prism page and avoid exposing the listener beyond your machine.
Workflow Chain
Then invoke: diffity resolve, diffity review
SKILL.md
READMESKILL.md - Diffity Diff
# Diffity Diff Skill You are opening the diffity diff viewer so the user can see their changes in the browser. ## Arguments - `ref` (optional): Git ref to diff (e.g. `main..feature`, `HEAD~3`) or a GitHub PR URL (e.g. `https://github.com/owner/repo/pull/123`). Defaults to working tree changes. ## Instructions 1. Check that `diffity` is available: run `which diffity`. If not found, install it with `npm install -g diffity`. 2. Run `diffity <ref>` (or just `diffity` if no ref) using the Bash tool with `run_in_background: true`: - The CLI handles everything: if an instance is already running for this repo it reuses it and opens the browser, otherwise it starts a new server and opens the browser. - Do NOT use `&` or `--quiet` — let the Bash tool handle backgrounding. 3. Wait 2 seconds, then run `diffity list --json` to get the port. 4. Tell the user diffity is running. Print the URL and keep it short — don't show session IDs, hashes, or other internals. Example: > Diffity is running at http://localhost:5391 > > When you're ready: > - Leave comments on the diff in your browser, then run **/diffity-resolve** to fix them > - Or run **/diffity-review** to get an AI code review