setup-browser-cookies

An agent skill by garrytan, from garrytan/gstack. Tags: browser, security, setup, web.

What it does

Import cookies from your real Chromium browser into the headless browse session. (gstack)

Install

With the skills CLI, which installs into Claude Code, Codex, Cursor and other agents:

npx skills add garrytan/gstack --skill setup-browser-cookies

Or copy the skill folder into Claude Code's skills directory by hand (~/.claude/skills for every project, or .claude/skills inside one):

git clone --depth 1 https://github.com/garrytan/gstack
cp -r gstack/setup-browser-cookies ~/.claude/skills/setup-browser-cookies

Safety box score

Grade D, elevated risk: 60 of 100 risk points, rated 2026-10-20. The grade rates what the skill and its scripts can reach on the machine of whoever installs it, across eight categories from shell execution to secrets access. How the score works.

This skill imports authenticated browser state from a real Chromium profile into a headless browsing session, so it can touch sensitive cookies, session tokens, and possibly Keychain-backed browser secrets. It also runs local helper binaries and can clear origin storage, so the main blast radius is account/session exposure plus local browser-data mutation.

Category levels, from 0 (none) to 3 (high)
Category	Level	Why
Code & shell execution	2 (moderate)	It runs local commands and shipped helpers such as `~/.claude/skills/gstack/bin/gstack-skill-start`, `$B goto`, `$B cookie-import-browser`, and `gstack-skill-end`, so it can execute code in the user's account.
Network access	1 (low)	The workflow deliberately connects the browser to user-chosen URLs and domains with `goto` and cookie import, but it is bounded to the sites the user names.
Filesystem reach	2 (moderate)	It reads browser profile directories, can clear `localStorage`/`sessionStorage` for an origin, and writes state/telemetry under home-dot paths like `~/.claude/skills/gstack/` and `~/.gstack/`.
Secrets & credentials	3 (high)	The skill's purpose is to import browser cookies/session tokens from a real profile, and it explicitly mentions macOS Keychain approval, so it can reach highly sensitive auth material.
Privilege & persistence	1 (low)	It does not request sudo or install services, but it may need user-granted Keychain access and writes into home directories.
Instruction hijack surface	2 (moderate)	It tells the agent to follow `GSTACK_INSTRUCTION_BEGIN...END` blocks emitted by `gstack-skill-start`, creating a runtime instruction channel that can be abused if the helper output is compromised.
Irreversible actions	1 (low)	It can perform browser-session setup and optional storage clearing, but it does not itself send messages, publish, pay, book, deploy, or delete outside the browser context.
Transparency	2 (moderate)	Core behavior is delegated to external helpers and `$B` commands that are not included in the reviewed source, so the real import and cleanup logic is not visible here.

Before installing

Read the implementation of `gstack-skill-start`, `gstack-skill-end`, and `$B` before trusting the workflow.
Test it first with a throwaway browser profile and a non-sensitive test domain.
Check exactly what `--clear-storage` removes and whether it can affect other tabs on the same origin.
Confirm whether the import path can access macOS Keychain or decrypt browser cookies on your machine.

Rated 2026-10-20 by an automated review of 1 file from the skill's repository.

Source

Repository: garrytan/gstack (all skills from this repository)
Path: setup-browser-cookies/SKILL.md
Branch: main
Updated: 2026-10-05

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