agentmods.dev

browser-harness AGENTS.md

Repository instructions for browser-harness, a tool that lets an agent control a web browser through Chrome's debugging connection. They explain the project layout, command-line tool, browser connection, recording rules, and workspace limits.

In plain words
What is it for?
Use them when building, testing, debugging, recording, or demonstrating browser-based work with browser-harness.
Why use it?
They help the agent operate the browser consistently and avoid editing the wrong files or repeating completed browser tasks. They also point to installation and troubleshooting guidance.

Instructions file for CodexOpenCode

17k 2d ago A scan 316 tokens original MIT
View the source file browser-use/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.

agentmods
npx agentmods add instructions/browser-use/browser-harness/agents-md
Clone the repo
git clone --depth 1 https://github.com/browser-use/browser-harness

Made for: Codex, OpenCode.

Per session 316 This file is loaded in full into every session.
When invoked 316 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
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 $0.00316 $0.00316
Opus 5 $0.00158 $0.00158
Sonnet 5 $0.00063 $0.00063
Haiku 4.5 $0.00032 $0.00032

Measured 2d ago against content hash 80b1176f8e91, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

browser-harness AGENTS.md 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 2d 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.

AGENTS.md · 32 lines

What it actually says

browser-harness is a thin layer that connects agents to browsers via an editable CDP harness.

Code priorities

  • Clarity
  • Precision
  • Low verbosity
  • Versatility

Overview

Core code lives in src/browser_harness/:

  • admin.py — daemon lifecycle, diagnostics, updates, profile management
  • daemon.py — the long-lived middleman process between the browser and the agent
  • helpers.py — CDP wrapper and core browser primitives auto-imported into -c scripts
  • run.py — the browser-harness CLI

SKILL.md tells agents how to use the harness and CLI. install.md tells agents how to install it, attach a browser, and troubleshoot. In this checkout, invoke the current source with ./browser-harness; do not use a globally installed browser-harness binary.

For recording or video tasks, follow SKILL.md and interaction-skills/make-video.md. A natural request to show, record, or demo the work opts in; significant work alone does not. Keep the exact path returned by start_recording() and never reenact a finished task.

An agent operating the harness only edits inside agent-workspace/:

  • agent_helpers.py — task-specific browser helpers the agent adds
  • domain-skills/ — skills the agent writes and reads

Contributing

Consider what is really needed. Prefer the smallest diff that fixes the bug.

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. 2d ago First seen · 32 lines · 316 tokens per session scan A 80b1176f8e91

Subscribe to this mod's changes

browser-harness AGENTS.md is an instructions file published in the GitHub repository browser-use/browser-harness (17,240 stars, last pushed 2d ago), licensed MIT. It adds 316 tokens to every session, about $0.0016 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.

Data and AIDebuggingTestingai-agentbrowser-agentbrowser-automationbrowser-usecdpcloud-browser
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