🧪 Litmus

The litmus test for a fix — prove it's real, in the real app.

A Claude Code skill that enforces one rule:

A ticket isn't "done" until you've reproduced the defect in the running app — and watched it disappear.

"It deployed." A green unit test. A backend curl. A row in the DB. None of those count. Litmus is the discipline that closes the gap between "I changed the code" and "the user's problem is actually gone."

Why it exists

"Fixed" too often means "I edited the code and it deployed" — then QA reopens it. Litmus drives the real app as the reporting user, reproduces the exact ticket steps, instruments the live request/response + front-end state + database, and only updates the tracker when it can show the defect and its absence, with evidence.

What /litmus does

1. Read the ticket — user, steps, actual, expected, screen URL.
2. Open the app as that user — via the app's own "sign in as" (you type the password — never the skill).
3. Reproduce the exact steps; screenshot the failing state; confirm it matches actual.
4. Instrument the live app — hook both fetch and XHR, read front-end scope (e.g. AngularJS), query the DB through a relay with a real driver.
5. Prove defect → fix with concrete before/after: the payload now carries the right value · the list is de-duped · the exact DB row is correct.
6. Update the tracker with the evidence — then revert any test data and tear down relays.

What it refuses to do — by design

• ❌ Close a ticket on deploy / unit-test / DB-only evidence
• ❌ Type or submit your password (you do that)
• ❌ Make destructive shared-data changes without a backup and a human's OK
• ❌ "Fix" an access gap by changing permissions itself — it flags it instead

Install

/plugin marketplace add https://github.com/hacka0wi/Litmus
/plugin install litmus@litmus

After install, /litmus is available in every project / session and auto-triggers when you're about to verify or close a ticket — or just say "verify this", "prove it's fixed", "reproduce it live".

Update: /plugin marketplace update litmus (bump version in both manifests on changes).

Field-tested gotchas (baked into the skill)

• Hook both fetch and XHR — an XHR-only hook misses modern SPA calls.
• Trust the live DB definition of procs/functions as canonical, not the repo .sql, if your team edits the DB directly.
• Verify counts/dups from front-end state, not the paginated rendered list.
• Confirm the deployed code actually contains the fix (fn.toString().includes('…')) — not just that it shipped.

Structure

.claude-plugin/marketplace.json       # marketplace manifest (name: litmus)
plugins/litmus/
  .claude-plugin/plugin.json           # plugin manifest
  skills/litmus/SKILL.md               # the /litmus skill (generic — no secrets)

Environment specifics (hosts, credentials, tracker ids, DB relays) are intentionally not in this public skill — keep them in your own private config / agent memory.

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_{Built with Claude Code · MIT}