opentabs AGENTS.md

Project instructions for OpenTabs, a Chrome extension and local MCP server that lets coding agents interact with web applications through an authenticated browser.

In plain words
What is it for?
Use them when developing or debugging OpenTabs plugins, the MCP server, Chrome-extension adapters, plugin discovery, or communication between the agent and browser.
Why use it?
They explain how the extension, server, and plugins communicate and how plugins are discovered and injected into matching browser tabs. This gives contributors the context needed to work within the project’s architecture.

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

Made for: Codex, OpenCode.

Per session 7,070 This file is loaded in full into every session.
When invoked 7,070 The same file — it is already loaded in full.
Security scan B 2 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 $0.07070 $0.07070
Opus 5 $0.03535 $0.03535
Sonnet 5 $0.01414 $0.01414
Haiku 4.5 $0.00707 $0.00707

Measured 3d ago against content hash b0cac6e4d3ca, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade B, and why

opentabs AGENTS.md scanned grade B with 2 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 3d 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.

Asks for rootmediumPrivilege escalation

A mod that escalates privileges can change anything on the machine, not only the project.

ssh pc "sudo systemctl stop ralph-consolidator" # Stop the consolidator

Runs shell commandslowCapability

Expected in a hook, worth knowing in a rule or an instructions file.

**Production code** (`platform/*/src/`): Uses Node.js APIs directly (`node:fs/promises`, `node:child_process`, `node:crypto`, `process.env`, `process.argv`).
Origin

Copies of this mod

1 near-identical copy found in the catalogue:

AGENTS.md · 463 lines

How it starts

The opening of the file, as written. The whole thing — 463 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Project Instructions for Codex

Project Overview

OpenTabs Platform is a Chrome extension + MCP server with a plugin-based architecture. A plugin SDK allows anyone to create OpenTabs plugins as standalone npm packages. The MCP server discovers plugins at runtime, and the Chrome extension dynamically injects plugin adapters into matching tabs — giving AI agents access to web applications through the user's authenticated browser session.

Architecture

┌─────────────┐  Streamable HTTP  ┌─────────────┐  WebSocket  ┌──────────────────┐
│ Codex │ ←───────────────→ │ MCP Server  │ ←─────────→ │ Chrome Extension │
│             │  /mcp             │ (localhost) │             │   (Background)   │
└─────────────┘                   └──────┬──────┘             └────────┬─────────┘
                                         │                             │
                                  ┌──────▼──────┐            ┌────────▼─────────┐
                                  │   Plugin    │            │  Adapter IIFEs   │
                                  │  Discovery  │            │  (per plugin,    │
                                  │ (npm + local│            │   injected into  │
                                  │  paths)     │            │   matching tabs) │
                                  └─────────────┘            └────────┬─────────┘
                                                                      │ Same-origin
                                                             ┌────────▼─────────┐
                                                             │   Web APIs       │
                                                             │ (user's session) │
                                                             └──────────────────┘

MCP Server (platform/mcp-server): Plugin discovery, tool dispatch via WebSocket, browser tools, audit log. See platform/mcp-server/AGENTS.md for details.

Chrome Extension (platform/browser-extension): Adapter injection, tool dispatch relay, React side panel UI. Published to npm as @opentabs-dev/browser-extension and bundled as a CLI dependency so opentabs start can auto-install it. See platform/browser-extension/AGENTS.md for details.

Read the full file on GitHub · 463 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. 3d ago First seen · 463 lines · 7,070 tokens per session scan B b0cac6e4d3ca

Subscribe to this mod's changes

opentabs AGENTS.md is an instructions file published in the GitHub repository opentabs-dev/opentabs (926 stars, last pushed 9d ago), licensed MIT. It adds 7,070 tokens to every session, about $0.0353 per session on Opus 5. A static security scan graded it B with 2 findings (asks for root, runs shell commands). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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