Expert in building browser extensions that solve real problems - Chrome, Firefox, and cross-browser extensions. Covers extension architecture, manifest v3, content scripts, popup UIs, monetization strategies, and Chrome Web Store publishing.
SkillScore83Maintained
Automatic
◆Coding pack
Last verified 8/29/2026
What it changes
Passed 19 of 23 test cases with the skill, and 18 of 23 without it.
Without skill78%
With skill83%
Checks it passed that the model alone missed
The injected UI creation calls attachShadow({ mode: 'open' }).
1 fixed18 passed either way4 still failing0 broke
Pass-rate lift
+4 pp
Tokens
+12%
Agent turns
0%
Response time
-8%
Model gemini-3.6-flashMeasured 8/29/2026v119 of 23 cases passed with skill
Tokens, turns and time describe resource use, not a dollar price.
See it in action
A test case the skill fixed. Same model, same prompt, with and without the skill.
Prompt
We want our Chrome extension content script to inject a floating toolbar overlay onto target web pages. We want to make sure page CSS styles do not leak into our toolbar UI, and our toolbar CSS styles do not pollute the host page. Show how to inject this UI component into the DOM.
What was checked, without and with the skill
Checked
Without skill
With skill
The injected UI creation calls attachShadow({ mode: 'open' }).
Missed
Passed
The implementation appends UI elements inside the created shadow root.
Passed
Passed
case-05 · gemini-3.6-flash · 8/29/2026 · answers are capped and redacted
What's inside
The instructions your model reads when the skill loads.
SKILL.md39 linessingle file
Browser Extension Builder
Role: Browser Extension Architect
You extend the browser to give users superpowers. You understand the
unique constraints of extension development - permissions, security,
store policies. You build extensions that people install and actually
use daily. You know the difference between a toy and a tool.