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 PaulRBerg/agent-skills --skill chromium-browsergit clone --depth 1 https://github.com/PaulRBerg/agent-skillsWrote 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/paulrberg/agent-skills/chromium-browser)<a href="https://agentmods.dev/skills/paulrberg/agent-skills/chromium-browser"><img src="https://agentmods.dev/badge/skills/paulrberg/agent-skills/chromium-browser/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/paulrberg/agent-skills/chromium-browser"><img src="https://agentmods.dev/badge/skills/paulrberg/agent-skills/chromium-browser.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 1 finding, up to medium
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- medium Rogue Agent · line 20 Skill establishes unauthorized persistence across sessions via cron jobs, startup scripts, or state files. Session persistence allows an attacker to maintain access beyond the current interaction.Fix: Remove any persistence mechanisms (cron jobs, startup scripts, state files). Skills should not maintain state across sessions without explicit user consent.
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 | $0.00047 | $0.01016 |
| Opus 5 | $0.00023 | $0.00508 |
| Sonnet 5 | $0.00009 | $0.00203 |
| Haiku 4.5 | $0.00005 | $0.00102 |
Grade A, and why
chromium-browser 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 11d 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 — 80 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Chromium Browser
Operate the configured Chrome DevTools MCP against the existing shared browser without disrupting unrelated tabs or authenticated state.
Environment Contract
- Treat
~/.local/libexec/mcp/chrome-devtoolsand the tools exposed in the current session as authoritative. The wrapper owns server versioning, flags, logging, and browser attachment; do not run the MCP package directly. - The MCP attaches to an existing remote-debugging browser. Never launch a fallback browser or create another profile when attachment fails.
- Treat the browser as shared, authenticated, and concurrently used by the user and other agents. Inspect only pages relevant to the task and do not surface unrelated tab titles or content.
- Trust the live tool inventory; an absent tool is unavailable in this session. Do not advise editing client MCP configuration as a troubleshooting shortcut.
Reference Routing
For Wayback Machine capture discovery or replay research, read references/wayback-machine.md before making any Wayback
request. Otherwise do not load it. Discover captures through serialized APIs outside Chromium, then open only the
selected replay when rendered inspection adds evidence.
Page Ownership
- Call
list_pagesbefore interacting and preserve the initial pages as pre-existing state. - Prefer
new_pagewithbackground: truewhen a fresh page satisfies the task. Record the exactpageIdreturned by every page this task creates; never infer ownership from a later page-list difference. - Pass an explicit
pageIdto every page-scoped tool. Do not rely on selected-page state; useselect_pageonly when deliberately bringing a page to the foreground. - Navigate or mutate a pre-existing page only when the task explicitly depends on that page's current state. Never close a pre-existing page.
- At completion, close only the recorded pages created by this task unless the user asked to leave one open.
Interaction and Evidence
- On one page, navigate, wait for a useful known signal, take a fresh snapshot, then interact with identifiers from that snapshot. Refresh it after navigation or meaningful DOM changes.
- Prefer
take_snapshotfor structure and automation,take_screenshotfor visual evidence, andevaluate_scriptfor information absent from the accessibility tree. Accept wrapper screenshot defaults unless the task requires lossless or full-resolution output. - Keep action responses small with
includeSnapshot: falseunless the updated state is immediately needed. Paginate and filter console, network, memory, and other high-volume results. - When a cookie consent popup appears, select only necessary or essential cookies by default, including through its settings when needed. If no such option is available, accept all cookies and continue.
- Use
filePathfor large screenshots, snapshots, traces, recordings, or response bodies, writing only to a task-authorized workspace path or a temporary location. Unrestricted path capability is not write authorization. - Parallelize independent pages when useful, but preserve causal order for calls targeting the same page.
What ships with it
2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 11d ago First seen · 80 lines · 47 tokens per session scan A 793218728dab
chromium-browser is a skill published in the GitHub repository PaulRBerg/agent-skills (70 stars, last pushed today), licensed MIT. It adds 47 tokens to every session and 1,016 once invoked, about $0.0002 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 2026-08-30.
Other skills, from other repositories
chrome-devtools-cli
Use this skill to write shell scripts or run shell commands to automate tasks in the browser or otherwise use Chrome DevTools via CLI.
a11y-debugging
Uses Chrome DevTools MCP for accessibility (a11y) debugging and auditing based on web.dev guidelines. Use when testing semantic HTML, ARIA labels, focus states, keyboard navigation, tap targets, and color contrast.
chrome-devtools
Uses Chrome DevTools via MCP for efficient debugging, troubleshooting and browser automation. Use when debugging web pages, automating browser interactions, analyzing performance, or inspecting network requests. This skill does not apply to --slim mode (MCP configuration).
chrome-performance-optimizer
Autonomous multi-agent performance optimization loop for Chromium and V8. Supports profile-seeded mode (analyzing Speedometer 3 / JetStream profiles via pprof or Sagacity MCP) and pattern-driven discovery mode (fan-out exploration of Blink and V8 macro-patterns grounded in historical wins and past rejected CLs).…
nullaway
Guide for resolving NullAway static analysis errors. Best practices for: Passing ObservableSupplier/Supplier Dereferencing potentially @Nullable values Adding @NullMarked to Java code.
bisect
Bisect regressions or broken builds in the Chromium repository using deterministic binary search, checking out midpoint commits, syncing dependencies with gclient sync, compiling the target with autoninja, and querying the user for test results until the culprit commit is isolated.