neobrowser AGENTS.md

neobrowser AGENTS.md is an instructions file for Codex, OpenCode from pitiflautico/neobrowser. It costs 1,759 tokens per session, scanned A, original, MIT.

A repository guide for NeoBrowser, an MCP server that lets AI models control a real Google Chrome browser through Chrome's developer interface. It documents the Rust product, archived Python code, build commands, tests, and tools.

In plain words
What is it for?
It supports building, testing, formatting, linting, diagnosing the environment, regenerating tool documentation, and running the browser demo.
Why use it?
It helps contributors work on the maintained implementation without confusing it with the archived version or skipping required checks.

Instructions file for CodexOpenCode

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/pitiflautico/neobrowser/agents-md
Clone the repo
git clone --depth 1 https://github.com/pitiflautico/neobrowser

Made for: Codex, OpenCode.

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 neobrowser AGENTS.md

README.md
[![agentmods](https://agentmods.dev/badge/instructions/pitiflautico/neobrowser/agents-md.svg)](https://agentmods.dev/instructions/pitiflautico/neobrowser/agents-md)
Your own site
<a href="https://agentmods.dev/instructions/pitiflautico/neobrowser/agents-md"><img src="https://agentmods.dev/badge/instructions/pitiflautico/neobrowser/agents-md.svg" alt="Measured on agentmods" height="20"></a>
Per session 1,759 This file is loaded in full into every session.
When invoked 1,759 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 5.1 $0.01759 $0.01759
Opus 5 $0.00879 $0.00879
Sonnet 5 $0.00352 $0.00352
Haiku 4.5 $0.00176 $0.00176

Measured 5d ago against content hash 4f2548d7fc50, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade A, and why

neobrowser 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 5d 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 · 88 lines

How it starts

The opening of the file, as written. The whole thing — 88 lines — stays where its author put it; the contents beside it link to each section on GitHub.

AGENTS.md — orientation for AI agents & contributors

NeoBrowser is an MCP server that drives a real Google Chrome via the Chrome DevTools Protocol (CDP) so AI models can use the web autonomously — stealthily, and optionally with the user's real logged-in sessions.

There are two implementations:

  • rust/ — the shipped product. A single ~5.5 MB binary (dynamically linked against the platform libc, not fully static). All new work goes here.
  • archive/python-oracle/ — the original Python implementation, archived. Not the product, not maintained; its README explains why it stopped being a useful oracle.

Build, run, test (Rust — primary)

cd rust
cargo build --release            # -> target/release/neobrowser
cargo test                       # unit + 1 live-Chrome integration test (self-skips w/o Chrome)
cargo fmt --check && cargo clippy --all-targets -- -D warnings   # CI gate
./target/release/neobrowser doctor       # environment check
./target/release/neobrowser tools --markdown > ../docs/TOOLS.md   # regenerate tool docs
python3 scripts/demo.py          # end-to-end demo against real sites
node --version                   # one test syntax-checks the JS embedded in the Rust

Archived Python oracle: cd archive/python-oracle && pip install -e ".[dev]" && python -m pytest -q.

How it works (Rust module map)

module role
cdp CDP protocol client on tokio: one connection task multiplexes commands (routed by id) and events; typed timeouts; drains on disconnect
chrome Chrome discovery/launch, stealth flags, health checks; Drop reaps the process
browser Owns the shared Chrome + tabs; lazy launch/attach; self-healing; multi-tab
capture Background listener buffering console + network events per tab
page Page-level CDP verbs (navigate, read, click, type, screenshot, find, nudge_frame)
ops JS-blob tools (fill, form_fill, submit, extract, analyze, scroll, …)
sessions Cookie snapshot/restore, save_session, scripted login
cookies Cross-platform real-profile cookie decryption (Keychain/secret-service/DPAPI)
reach browse/upload/download with an SSRF guard
search Multi-provider search that skips walled sources
policy Central pre-dispatch decision: action class, domain allow/deny, profile (developer/safe/autonomous)
action Verified-action envelope, time budgets, observe → act → verify
observe Accessibility snapshots with stable refs, and diffs between them
vault Encrypted-at-rest session material, TTL, verifiable revocation
untrusted Fencing and labelling page content; injection detection
trace Correlated event timeline, secret redaction, evidence bundles
devtools Web Vitals, computed styles, response bodies, HAR export
frames Shadow DOM / iframe piercing, dialogs, device emulation
bridge Authenticated localhost queue for the Chrome Bridge extension
config Versioned config file, env overrides, named profiles
walls Generic bot-wall / captcha / consent / rate-limit / login detection
stealth JS anti-detection patch (genuine, not spoofed)
llm Optional LLM find fallback (opt-in via ANTHROPIC_API_KEY)
playbook Record/replay tool sequences
tools / tool_impls / mcp Tool trait + registry + argument validation + JSON-RPC server

Read the full file on GitHub · 88 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. 5d ago First seen · 88 lines · 1,759 tokens per session scan A 4f2548d7fc50

Subscribe to this mod's changes

neobrowser AGENTS.md is an instructions file published in the GitHub repository pitiflautico/neobrowser (99 stars, last pushed 9d ago), licensed MIT. It adds 1,759 tokens to every session, about $0.0088 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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