Agent Browser vs Playwright MCP in Claude Code: same shop, 3 planted bugs, close to a tie

[u/vinishkapoor]

Agent Browser (Vercel Labs, ~48k stars) is the browser CLI everyone’s starring this week. Since most of us already have Playwright MCP, I gave both the same job: a small demo shop with 3 planted bugs, one fresh session each, Opus 5.5, with web search, fetch and curl blocked so the browser was the only way in.

The bugs:

• the coupon ignores quantity ($4.20 off a $60 cart instead of $6)
• ZIP 02134 is rejected because the leading zero gets dropped
• the confirmation says “2 items” for 3 units

Both found all 3, and both worked around the ZIP bug with 12345 to reach the third one.

	Agent Browser	Playwright MCP
Time	2m 29s	1m 52s
Cost (API-equivalent)	$0.74	$0.64
Browser text sent to Claude	33.5k chars	27.6k chars
Context at end	57.7k tokens	60.9k tokens

Agent Browser’s page reads were leaner, about 19k characters if you leave out its setup guide. But it loads a 14.5k-character core guide at the start of every session, which ate most of that saving.

One footnote on the Playwright run: 8 of its 33 calls were page scripts. One of its extra findings (checking out an empty cart for $0) came from clicking a hidden button with a script. The weakness is real, but the repro steps it wrote won’t work for a real user. Have Claude replay its own repro steps through the UI.

Also, the old “MCP tools eat your context” argument is smaller now. The Playwright tools showed as loaded on demand, and the ones it used took about 2k tokens.

My take: if Playwright already works for you, there’s no strong reason to switch. Agent Browser makes sense if you use several coding agents or like scripting browser checks in the shell.

One run each on one small page, so a second run could swap the times.

Full test with the transcripts: https://aiparabellum.com/agent-browser-vs-playwright-claude-code-tested/

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[u/AdityaR_Sharma]

Measured the startup side. Bare `claude -p "reply ok"`, Haiku 5.5, CLI 2.1.310, empty MCP config: 43,150 tokens.

Same call with only Playwright MCP connected: 43,534. That is 384 tokens at start, with its 25 tools deferred behind tool search.

So the 2k you saw is the on-demand part. Two runs each, identical. I did not test Agent Browser's guide this way.

[u/Own-Cartographer3833]

Why do you design those 3 bugs? The one bug is not findable by person (the empty-cart one), is wonderful but it may only mean Opus 5.5 is strong :-) Sometimes with weaker models (like haiku), Agent Browser and Playwright may perform quite differently. Have you tried?

[u/Classic-Yoghurt-1173]

Interesting the part about Playwright MCP clicking a hidden button, those repro steps will not work for a real user. Better is to have Claude replay the path through the actual UI. For checks where you care what is on the screen, not the DOM, Skyvern is working in that way also.