browser-harness

browser-harness is a skill for Claude Code from zpoint/vibe-seller. It costs 83 tokens per session (5,505 once invoked), scanned A, original, Apache-2.0.

Instructions for controlling a web browser with browser-use 0.13 through Python code piped into a helper script. It explains store-specific sessions, public-web sessions, login boundaries, and the available helper interface.

In plain words
What is it for?
Automating seller-center tasks for a store, using auxiliary browser sessions for other sites, and carrying out public searches or logistics research without logging into store accounts.
Why use it?
It prevents commands written for older browser-use versions from failing and separates store account work from neutral public-web research.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter. Also seen: mentions subagents.

Good fit Automating seller-center tasks for a store, using auxiliary browser sessions for other sites, and carrying out public searches or logistics research without logging into store accounts.

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Install with agentmods
npx agentmods add skills/zpoint/vibe-seller/browser-harness
Install

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.

Any agent
npx skills add zpoint/vibe-seller --skill browser-harness
Clone the repo
git clone --depth 1 https://github.com/zpoint/vibe-seller

Made for: Claude Code.

Wrote 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.

agentmods badge for browser-harness

README.md
[![agentmods](https://agentmods.dev/badge/skills/zpoint/vibe-seller/browser-harness/github.svg)](https://agentmods.dev/skills/zpoint/vibe-seller/browser-harness)
Your own site
<a href="https://agentmods.dev/skills/zpoint/vibe-seller/browser-harness"><img src="https://agentmods.dev/badge/skills/zpoint/vibe-seller/browser-harness/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.

agentmods 80×15 button for browser-harness

Your own site · 80×15
<a href="https://agentmods.dev/skills/zpoint/vibe-seller/browser-harness"><img src="https://agentmods.dev/badge/skills/zpoint/vibe-seller/browser-harness.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 83 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 5,505 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 3 findings, 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 Agent Snooping · line 8
    Skill enumerates or reads other installed skills. Access to other skills' SKILL.md files or the skills directory reveals prompt instructions, capabilities, and secrets that should be invisible to peer skills.
    Fix: Remove all code or instructions that list or read other skills' files or directories. Skills should operate independently; cross-skill access is a privilege escalation.
  • medium Rogue Agent · line 32
    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.
  • medium Rogue Agent · line 321
    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.
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00083 $0.05505
Opus 5 $0.00042 $0.02753
Sonnet 5 $0.00017 $0.01101
Haiku 4.5 $0.00008 $0.00551

Measured 10d ago against content hash 0f9826ecd657, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

browser-harness 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 10d 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.

app/skills_v2/browser-harness/SKILL.md · 441 lines

How it starts

The opening of the file, as written. The whole thing — 441 lines — stays where its author put it; the contents beside it link to each section on GitHub.

browser-use 0.13 changed everything. There are no subcommands. You no longer run browser-use open <url>. Instead you pipe Python helper code to browser-use via a heredoc; helpers are pre-imported and a background daemon is attached automatically.

Store Tasks: browser-use is a per-store wrapper script that auto-injects BU_NAME (the store session) and BU_CDP_WS (the store's CDP proxy). You cannot set BU_NAME, BU_CDP_URL, BU_CDP_WS, or --mcp yourself — the wrapper blocks them. Use the default session for the store's seller center, or --session <slug>-aux for non-seller-center sites (the wrapper maps this to the aux session; no other --session value is allowed).

No-store (orchestrator) Tasks: browser-use is the store-less web wrapper (bin/_web). Use it only for neutral public web work (search, tracking/logistics, research) — NEVER for a store's seller center or to log into store/platform accounts (create a store sub-task for those).

Browser Automation with browser-use (0.13, heredoc interface)

Drive the browser by piping Python to browser-use. Helpers are pre-imported; the harness calls ensure_daemon() before running your code, so the browser attaches automatically to the store's CDP endpoint.

browser-use <<'PY'
new_tab("https://example.com")   # first navigation is new_tab(), NOT goto
wait_for_load()
print(page_info())
PY

The wrapper takes the heredoc form only — there is no -c flag (passing one just prints usage). Put every statement inside the heredoc.

Read the full file on GitHub · 441 lines

Changes

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.

  1. 10d ago First seen · 441 lines · 83 tokens per session scan A 0f9826ecd657

Subscribe to this mod's changes

browser-harness is a skill published in the GitHub repository zpoint/vibe-seller (66 stars, last pushed yesterday), licensed Apache-2.0. It adds 83 tokens to every session and 5,505 once invoked, about $0.0004 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.

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