Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add ntorga/agent-starter-kit --skill browser-inspectgit clone --depth 1 https://github.com/ntorga/agent-starter-kitWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/ntorga/agent-starter-kit/browser-inspect)<a href="https://agentmods.dev/skills/ntorga/agent-starter-kit/browser-inspect"><img src="https://agentmods.dev/badge/skills/ntorga/agent-starter-kit/browser-inspect/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/ntorga/agent-starter-kit/browser-inspect"><img src="https://agentmods.dev/badge/skills/ntorga/agent-starter-kit/browser-inspect.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00016 | $0.01756 |
| Opus 5 | $0.00008 | $0.00878 |
| Sonnet 5 | $0.00003 | $0.00351 |
| Haiku 4.5 | $0.00002 | $0.00176 |
Grade A, and why
browser-inspect scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 178 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Purpose
An agent editing UI code cannot confirm that the result is correct by reading source files alone. CSS can be purged or overridden, client-side JS only runs in the browser, and server-rendered markup may differ from what the template suggests. Without looking at the live page, an agent is guessing. This skill codifies how to inspect, interact with, and verify rendered web UI using two complementary tools that serve different purposes.
Procedure
1. Tool selection
Two tools exist for browser work. They are not interchangeable — the distinction is which browser instance you connect to.
- agent-browser: Spins up its own fresh session. Use for autonomous tasks: testing, form automation, screenshots, clean-state QA.
- Chrome DevTools MCP: Attaches to the user's live browser. Use for collaborative debugging: inspecting existing state, auth sessions, HMR.
agent-browser is a free CLI tool — harness-agnostic, works everywhere, no API key:
npm install -g agent-browser
agent-browser install # downloads Chrome for Testing (first time only)
Verify it before use: run command -v agent-browser. If it is missing, show the user the two install commands above and stop. Installing a global npm package and downloading a browser are system changes — the user runs them or explicitly approves them first. Once installed, continue.
Always use --engine chrome. Lightpanda has no rendering engine and cannot display visual output.
Chrome DevTools MCP is an MCP server — requires registration in the harness's MCP config. If the MCP server is not available, ask the user to add it to opencode.json (project) or ~/.config/opencode/opencode.json (global):
{
"mcp": {
"chrome-devtools": {
"type": "local",
"command": ["npx", "-y", "chrome-devtools-mcp@latest"]
}
}
}
The harness must be restarted after adding the config. The MCP server starts Chrome automatically on first tool use.
When to use which:
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 2d ago First seen · 178 lines · 16 tokens per session scan A e2da1057605e
browser-inspect is a skill published in the GitHub repository ntorga/agent-starter-kit (142 stars, last pushed 2d ago), licensed MIT. It adds 16 tokens to every session and 1,756 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-13.
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