The one-line difference
Playwright MCP drives a browser from the outside. Reticle runs inside your app. That single architectural choice explains every difference below. An outside-in tool can go anywhere and see anything rendered. An inside-out tool needs to be installed, and in exchange it can read things that were never rendered at all. Application state, emitted signals, the exact requests that fired.Measured, on the same app at the same moment
On a real production dashboard, observing once:
Reticle is about 2.1x leaner on a large page. The gap comes from what each tool sends: Playwright MCP returns the accessibility tree, and on a complex app that tree is enormous. Reticle asks narrower questions —
mode: "interactive" returns only controls, count_only returns a number.
How these were measured
The method, the scenarios, and the control where a false positive would count against us.
What Playwright MCP does better
This is not a courtesy section. There are real cases where Playwright is the correct choice and Reticle is not.- Sites you do not own. Reticle needs a dev-only SDK in the app. No SDK, no Reticle. Playwright drives anything with a URL, which is the entire point of it.
- Cross-browser. Firefox and WebKit are first-class in Playwright. Reticle’s real-input and screenshot paths are Chromium-oriented.
- True pixels. A screenshot is the actual rendered frame. A font that failed to load or a compositing glitch shows up there and can be missed by structural reads.
- Maturity and ecosystem. Playwright is a large, battle-tested project with an enormous community. We are not going to pretend otherwise.
What Reticle does that Playwright cannot
- Assert on the app’s own success signal. When your app emits
auth:granted, Reticle can require that exact signal. Playwright can check that a DOM element appeared, which a mock also does. - Read application state.
stateDiffsshowsauthmoving fromnullto a real user. A POST that returns200without touching state is caught here and nowhere else. - Map a DOM node to source.
src/components/Login.tsx:81, via the React fiber tree. Playwright can tell you the selector; it cannot tell you the file. - Grade its own evidence. Every verdict reports
honesty.grade:presence,stateorsignal. Plus whether the capture was clean and complete. - Say “unknown”. Reticle distinguishes “did not happen” from “I could not tell”. That third state is the difference between a check and a coin flip.
The false-green case
Here is the failure both tools face, and only one catches reliably. Your agent adds a “save” button. It calls an API. The API returns200. A row appears in the table. Reload the page and the row is gone, nothing was ever persisted.
Playwright MCP sees the row appear. That is a pass by every DOM-based check you could write.
Reticle sees stateDiffs: []. The store never changed. And fails the assertion, with the file and line of the button that lied.
Use both
They compose cleanly, and the combination is better than either alone:- Drive with Playwright when you need a browser context it is better at. A third-party OAuth flow, a cross-browser check, a genuine pixel diff.
- Assert with Reticle when the question is “did my app actually do the thing”.
reticle drive) that provides real CDP input and screenshots, so a lot of teams do not need both. Start with whichever matches the question you ask most often.
Choosing
Pick Playwright MCP
You are testing a site you do not own, you need Firefox or WebKit, or you need real pixel
comparison as the primary signal.
Pick Reticle
You own the app, an agent is editing it, and you want proof it worked rather than a screenshot
that looks fine.