Testing vs Other · both proven

differential-review vs internal-comms

Both skills were run through Claude twice: once on a fixed brief without the skill, once with it. The briefs differ because each is written for the job the skill claims to do, so compare each skill against its own baseline, then decide which difference matters for your work. They are in different categories, so this is a choice of job, not a head-to-head on the same job.

differential-review

Performs security-focused differential review of code changes. Adapts analysis depth to codebase size, uses git blame for context, calculates blast radius by counting callers, checks test coverage of modified code, and generates a markdown report. Use when reviewing a PR, commit, or diff for security vulnerabilities, checking whether a change re-introduces a previously fixed bug, asking what else…

Category: Testing
Source: trailofbits/skills
License: Other
Proof model: claude-opus-5-5
Brief: “Do a security-focused review of this change and present it as a single HTML page. Commit: "Allow admins to impersonate users for support" +app.get('/admin/impersonate/:id', async (req, res) => { + if (req.cookies.role !== 'admin') return res.sendStatus(403); + const user = await User.findById(req.params.id); + req.session.userId = user.id; + res.redirect(req.query.next || '/'); +});”
Skill commit: 2be6433

Without the skillWith differential-review

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Without, runWith differential-review, run3 independent runs per side, none selected by hand.

Download the with-skill page

internal-comms

A set of resources to help me write all kinds of internal communications, using the formats that my company likes to use. Claude should use this skill whenever asked to write some sort of internal communications (status reports, leadership updates, 3P updates, company newsletters, FAQs, incident reports, project updates, etc.).

Category: Other
Source: anthropics/skills
License: Not stated
Proof model: claude-opus-5-5
Brief: “Write this week's status update for the Checkout Redesign project as a single HTML page for the leadership channel. Facts to use: the new cart page shipped to 10% of traffic on Tuesday; conversion in the test group is up 2.1% so far; the payments team is two days late on the saved-cards work; a legal review of the new terms copy is still open; launch to 100% is planned for the 30th if the saved-cards work lands by Friday. Keep it short enough to read in a minute.”
Skill commit: dbd4588

Without the skillWith internal-comms

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Without, runWith internal-comms, run3 independent runs per side, none selected by hand.

Download the with-skill page

We don’t pick a winner for you: the pages are the evidence. Both proofs can be repeated with the brief, model and commit shown above. See alternatives to differential-review or alternatives to internal-comms.