Browser Login Agent Skill

Drive an authentication flow once, sanitize cookies through AIDefence, and vault a reusable cookie handle in browser-cookies for future…

Context cost
950 tokensestimated from the bundle, loaded when it triggers
Bundle
1 file · 3.8 kBtext throughout, nothing executable
Licence
MITthe author’s own terms
Last change
—no release on file
Servers it uses
Noneruns standalone

What it does

Drive an authentication flow once, sanitize cookies through AIDefence, and vault a reusable cookie handle in browser-cookies for future sessions

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.md3.8 kB · preview
--- name: browser-login argument-hint: "<login-url> [--vault-name <handle>] [--mfa]" allowed-tools: mcp__plugin_ruflo-core_ruflo__browser_open mcp__plugin_ruflo-core_ruflo__browser_close mcp__plugin_ruflo-core_ruflo__browser_fill mcp__plugin_ruflo-core_ruflo__browser_type mcp__plugin_ruflo-core_ruflo__browser_click mcp__plugin_ruflo-core_ruflo__browser_wait mcp__plugin_ruflo-core_ruflo__browser_eval mcp__plugin_ruflo-core_ruflo__browser_snapshot mcp__plugin_ruflo-core_ruflo__aidefence_scan mcp__plugin_ruflo-core_ruflo__aidefence_has_pii Bash Read Write ---
8# Browser Login
9
10Authenticate against a target site once, then vault the resulting session credentials so subsequent skills (browser-extract, browser-form-fill, browser-test) can reuse them without re-driving the auth flow. Borrows the pattern from Browserbase's cookie-sync/SKILL.md but stores the resulting context in AgentDB rather than on a hosted backend.
11
12## When to use
13
14- Establishing reusable auth for a host the agent will visit repeatedly.
15- Refreshing a vaulted cookie set whose expiry has passed.
16- Capturing an MFA-protected session that requires interactive completion.
17
18## Steps
19
201. **Open a recorded session** via browser-record.
212. **Drive the auth flow** — fill credentials with browser_fill / browser_type. Credentials come from the user or environment; do **not** read them from .env or paste them into the trajectory args.
223. **Handle MFA** (when --mfa): pause for user input or invoke the user's TOTP helper; capture only the resulting redirect, not the code itself.
234. **Capture cookie metadata, not values.** Run browser_eval with an expression that returns only each cookie's name, value length and a Shannon-entropy estimate, for example document.cookie.split('; ').map(c => { const [n, ...v] = c.split('='); return { name: n, length: v.join('=').length } }). Never return document.cookie itself: tool output goes straight into the model's context, so the raw values would be exposed before any gate runs. document.cookie also cannot see HttpOnly cookies, which are usually the session cookie; if the session is HttpOnly, record that fact and rely on the browser profile staying alive rather than on a captured value.
245. **Classify** each cookie from the metadata in step 4 (name pattern, length, entropy). Anything that looks like a session or auth token is vault-wrapped (an opaque handle) before AgentDB store; raw values never enter the namespace or the model's context.
256. **Store in browser-cookies**:
26 ```bash
This is a preview of SKILL.md. Download or install the skill to get the whole thing.
In the file
SKILL.md493 words
Files1
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.

≈180
always loaded
The name and description, so the model knows the skill exists and when to reach for it.
770
on trigger
The instruction body, read only when the skill fires.
0.47%
of a 200k window
Ten skills this size would take about 5% of the window before you open a file.
050k100k150k200k context window

950 tokens, estimated from the bundle at four bytes to the token, held for the rest of the session once it triggers. Small enough to keep loaded permanently without thinking about it.

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.

It asks the agent to write files, using whatever file access your client already has. Whether it reaches the network is not declared.

What it asks for
Writes filesyes
Network accessnot declared

Read from the allowed-tools line of this skill’s own SKILL.md. It also asks for Bash, which could do either, so what is not named there is not 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

1 file, 3.8 kB on disk. A bundle is text throughout: the instructions the model reads, plus the templates it fills in.

  • SKILL.md3.8 kB
What is not in it

No dependencies and nothing executable: a skill is text the agent reads, so the bundle is 1 file 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 Login · 950 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-login/bundle.tar.gz && tar -xzf "$t/bundle.tar.gz" -C "$t" && [ -d "$t/browser-login" ] && { [ ! -e .claude/skills/browser-login ] || { mv .claude/skills/browser-login "$t/.previous" && echo "Previous copy moved to $t/.previous"; }; } && mv "$t/browser-login" .claude/skills/ && echo "Installed .claude/skills/browser-login"
On Windows, or any OS with Node 20+
npx mcprush@latest skill add ruvnet/browser-login

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-login/ 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-login/bundle.tar.gz && tar -xzf "$t/bundle.tar.gz" -C "$t" && [ -d "$t/browser-login" ] && { [ ! -e ~/.claude/skills/browser-login ] || { mv ~/.claude/skills/browser-login "$t/.previous" && echo "Previous copy moved to $t/.previous"; }; } && mv "$t/browser-login" ~/.claude/skills/ && echo "Installed ~/.claude/skills/browser-login" (macOS, Linux) — or add --global to the npx line. The curl line replaces .claude/skills/browser-login/ 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
Referenceruvnet/browser-login

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
Servers2
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