Browser Trace Agent Skill

Capture a full DevTools-protocol trace of any browser automation — CDP firehose, screenshots, and DOM dumps — then bisect the stream into…

Context cost
11.3k tokensestimated from the bundle, loaded when it triggers
Bundle
13 files · 80.4 kB8 scripts among them — read before you run
Licence
MITthe author’s own terms
Last change
—no release on file
Servers it uses
Noneruns standalone

What it does

Capture a full DevTools-protocol trace of any browser automation — CDP firehose, screenshots, and DOM dumps — then bisect the stream into per-page searchable buckets. Use when the user wants to debug a failed run, audit network/console/DOM activity, attach a trace to an in-progress session, or feed structured per-page summaries back into an agent loop so its next iteration learns from the last one.

What this skill changes about the agent has not been set out here as a list. Its SKILL.md, shown below, says it in the author’s own words.

automationbrowser

The skill itself

A skill is instructions the model reads, so you can see what you are getting: below is the start of its SKILL.md. The front matter loads with every session, the body loads when the skill triggers, and the whole file comes with the install.

SKILL.md15.0 kB · preview
--- name: browser-trace compatibility: "Requires Node 18+, the browse CLI (`npm install -g browse`) with `browse cdp`, and optionally `jq` for ad-hoc querying of the bisected JSONL files. For remote Browserbase sessions, also requires `BROWSERBASE_API_KEY`. The skill scripts themselves use only the Node standard library — no `npm install` step." license: MIT allowed-tools: Bash, Read, Grep ---
9# Browser Trace
10
11Attach a **second, read-only CDP client** to a browser session that is already being driven by your main automation. The trace records the full DevTools firehose to NDJSON, polls for screenshots and DOM dumps in parallel, and slices everything into a directory tree that bash tools can search.
12
13This skill does **not** drive pages — it only listens. Pair it with the browser skill, browse, Stagehand, Playwright, or anything else that speaks CDP.
14
15## When to use
16
17- The user wants to debug a browser-automation run (failing form, missing element, hung navigation, JS exception).
18- The user has a running automation and wants to attach a trace mid-flight without restarting it.
19- The user wants to split a CDP firehose into network / console / DOM / page buckets.
20- The user wants screenshots + DOM snapshots over time, joined to CDP events by timestamp.
21
22If the user just wants to **drive** the browser, use the browser skill instead.
23
24## Setup check
25
26```bash
27node --version # require Node 18+
This is a preview of SKILL.md. Download or install the skill to get the whole thing.
In the file
SKILL.md1,977 words
Files13
LicenceMIT
Why you can read it

Nothing in a skill executes. The client loads the text and the model follows it, so a skill can be audited the way a runbook is — by reading it.

What it costs in context

Skills are not billed by the call. They are paid for in context: every token the instructions occupy is a token your code, your diff and your conversation cannot use. Here is what this one takes and when it takes it.

≈200
always loaded
The name and description, so the model knows the skill exists and when to reach for it.
11,150
on trigger
The instruction body and 12 supporting files, read only when the skill fires.
5.7%
of a 200k window
Ten skills this size would take about 57% of the window before you open a file.
050k100k150k200k context window

11.3k tokens, estimated from the bundle at four bytes to the token, held for the rest of the session once it triggers. Heavy. Teams tend to install this one per project rather than globally, and load it only when the job comes up.

Servers bill, skills cost

A server charges by the month. A skill charges once per session, in context, and then keeps charging it for as long as the session lives.

Before and after

The same question, put to the same model twice: once as it comes, and once with these instructions loaded.

No worked example has been published for this skill yet.

The procedure it runs

The procedure has not been set out here step by step. It is in the body of its SKILL.md: the start of it is shown above, and the whole file comes with the install.

Prose, not code

These steps are written for a model to follow, not executed by a runtime. It can still be told to skip one, and it will say so when it does.

Servers it uses

None. This skill calls no MCP servers at all.

Everything it needs is in the instructions, so it works in a project with nothing connected — the model reads the file and changes how it works with what it can already reach.

Its SKILL.md asks for Bash, which can write files and reach the network alike, so what it touches is whatever the instructions themselves ask for — read them before you install it.

What it asks for
Writes filesnot declared
Network accessnot declared

The allowed-tools line of this skill’s own SKILL.md asks for Bash, which could do either, so neither is ruled out. A skill grants no permissions of its own — it can only ask for tools your client already has.

What it will not do

Every skill is narrow, and the useful ones say where they stop. These are the jobs this one is the wrong tool for.

What this skill is not for has not been published here. Nothing is implied by that: it is a section the author has not filled in.

What is in the bundle

13 files, 80.4 kB on disk. Mostly text — the instructions the model reads — with 8 scripts in it that your client would run only if the instructions tell it to.

  • SKILL.md15.0 kB
  • EXAMPLES.md8.6 kB
  • LICENSE.txt1.1 kB
  • package.json0.1 kB
  • REFERENCE.md20.6 kB
  • scripts/bb-capture.mjs3.8 kB
  • scripts/bb-finalize.mjs3.2 kB
  • scripts/bisect-cdp.mjs7.8 kB
  • scripts/lib.mjs4.3 kB
  • scripts/query.mjs8.8 kB
  • scripts/snapshot-loop.mjs2.6 kB
  • scripts/start-capture.mjs3.0 kB
  • scripts/stop-capture.mjs1.5 kB
What is not in it

A skill installs nothing and depends on nothing: it is a folder your client reads. This one carries 8 scripts beside the text, so the bundle is 13 files you can review in full before installing. The MIT licence covers the templates and examples as well as the instructions.

Install

Installing copies the bundle into your project. Nothing runs at install time — the files sit on disk until the model reads them.

# Browser Trace · 11.3k tokens when loaded · macOS, Linux mkdir -p .claude/skills && t=$(mktemp -d) && curl -fsSL -o "$t/bundle.tar.gz" https://mcprush.com/api/skills/browser-trace/bundle.tar.gz && tar -xzf "$t/bundle.tar.gz" -C "$t" && [ -d "$t/browser-trace" ] && { [ ! -e .claude/skills/browser-trace ] || { mv .claude/skills/browser-trace "$t/.previous" && echo "Previous copy moved to $t/.previous"; }; } && mv "$t/browser-trace" .claude/skills/ && echo "Installed .claude/skills/browser-trace"
On Windows, or any OS with Node 20+
npx mcprush@latest skill add browserbase/browser-trace

Windows PowerShell says 'running scripts is disabled on this system'? Run Set-ExecutionPolicy -Scope CurrentUser RemoteSigned once, or type npx.cmd instead of npx (codex.cmd, gemini.cmd, grok.cmd likewise). PowerShell 7 needs neither. Writes to .claude/skills/browser-trace/ in the current project. For every project instead, run mkdir -p ~/.claude/skills && t=$(mktemp -d) && curl -fsSL -o "$t/bundle.tar.gz" https://mcprush.com/api/skills/browser-trace/bundle.tar.gz && tar -xzf "$t/bundle.tar.gz" -C "$t" && [ -d "$t/browser-trace" ] && { [ ! -e ~/.claude/skills/browser-trace ] || { mv ~/.claude/skills/browser-trace "$t/.previous" && echo "Previous copy moved to $t/.previous"; }; } && mv "$t/browser-trace" ~/.claude/skills/ && echo "Installed ~/.claude/skills/browser-trace" (macOS, Linux) — or add --global to the npx line. The curl line replaces .claude/skills/browser-trace/ only after the download succeeds, so files left there by another skill of the same name, or by an older release, do not mix in. A copy already there is moved aside, not deleted, and the line prints where.

Which clients pick it up on their own

A skill is a folder of text. Most of these read a skills folder and pick it up without being told; the rest take the same folder another way — an upload in the app, a parameter on an API call — and then choose it by its description just the same.

Claude Code.claude/skills/
Claude DesktopCustomize › Skills
ChatGPTSkills › Create › Upload
Cursor.cursor/skills/
VS Code.github/skills/
Codex CLI.agents/skills/
Gemini CLI.gemini/skills/
Grok Build.grok/skills/
Microsoft CopilotSkills › Upload a skill
PerplexityComputer › Skills › Upload a skill
DeepSeek Harness.dsh/skills/
Zed.agents/skills/
Devin Desktop.devin/skills/
Windsurf (legacy).windsurf/skills/
OpenAI Agents SDKInstructions or sandbox Skills
HTTP / APIa request parameter
This release
Versionnot versioned
Publishedno release date on file
PriceFree
Referencebrowserbase/browser-trace

Versions

Its author publishes no version number, so there is nothing here to pin to: what you install is the folder as it stands today. Instructions change more often than APIs do — a skill can be rewritten entirely without anything it depends on moving.

Pinning

Nothing to pin to: this skill carries no version number of its own. What you install is what the folder holds on the day you install it.

Reviews

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Publisher
Servers1
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