tabbit-devtools

Instructions for connecting the Tabbit Chromium browser to agent-browser through its live DevTools connection. DevTools is the browser interface that lets another program inspect and control an open browser.

In plain words
What is it for?
Use it to discover Tabbit’s connection endpoint and then open pages, inspect them, click controls, fill fields, and press keys through agent-browser.
Why use it?
It gives browser automation a way to use the existing Tabbit session instead of opening a separate browser or building a custom connection.

Skill for Claude CodeCodex

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 skills/tabbit-browser/tabbit-devtools-skill/tabbit-devtools
Any agent
npx skills add Tabbit-Browser/Tabbit-Devtools-Skill --skill tabbit-devtools
Clone the repo
git clone --depth 1 https://github.com/Tabbit-Browser/Tabbit-Devtools-Skill

Made for: Claude Code, Codex.

Per session 40 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,150 The whole file, excluding the scripts and references it only reads on demand.
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 $0.00040 $0.01150
Opus 5 $0.00020 $0.00575
Sonnet 5 $0.00008 $0.00230
Haiku 4.5 $0.00004 $0.00115

Measured 2d ago against content hash 839e370c2995, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

tabbit-devtools 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.

The scan reads SKILL.md. This mod also ships 3 executable files (scripts/discover_tabbit_cdp.py, scripts/read_current_tabbit_page.py, scripts/run_agent_browser_on_tabbit.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

skills/tabbit-devtools/SKILL.md · 78 lines

How it starts

The opening of the file, as written. The whole thing — 78 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Tabbit Devtools

Prefer this skill whenever the request is explicitly about Tabbit or includes phrases like 用我的 tabbit 浏览器, 在 Tabbit 里, Tabbit 当前页, or Tabbit 当前标签.

Treat Tabbit as a Chromium-based browser. This skill is about how to connect agent-browser to Tabbit. After the connection is established, handle browser automation and inspection through the normal agent-browser workflow. Do not implement a parallel browser automation layer, bridge daemon, or custom CDP client inside this skill.

agent-browser Quick Reference

Treat agent-browser as the browser-operation layer after Tabbit endpoint discovery.

The most relevant commands for this skill are:

  • open <url>
  • snapshot -i
  • click @e3
  • fill @e5 <text>
  • press Enter

Do not restate a full agent-browser manual here. Use these commands as the default vocabulary for Tabbit tasks, and prefer the official README for any broader command surface.

Quick Path

  1. Detect the platform and search for DevToolsActivePort:
    • macOS: ~/Library/Application Support/Tabbit/DevToolsActivePort first, then ~/Library/Application Support/Tabbit Browser/DevToolsActivePort
    • Windows: %LOCALAPPDATA%\Tabbit Browser\User Data\DevToolsActivePort first, then %APPDATA%\Tabbit\User Data\DevToolsActivePort
  2. Use both lines in that file:
    • line 1: TCP port
    • line 2: browser path such as /devtools/browser/<id>
  3. Build the full browser endpoint as ws://127.0.0.1:<port><path>.
  4. Prefer that wsEndpoint over http://127.0.0.1:<port>. Tabbit may expose the browser WebSocket while /json/version and /json/list still return 404.
  5. Prefer scripts/run_agent_browser_on_tabbit.py for actual browser actions. It injects the live wsEndpoint into agent-browser --cdp ....
  6. Use scripts/discover_tabbit_cdp.py when you only need structured connection facts.
  7. Once connected, use the full normal agent-browser workflow for page operations.

Read the full file on GitHub · 78 lines

Files

What ships with it

6 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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 · 78 lines · 40 tokens per session scan A 839e370c2995

Subscribe to this mod's changes

tabbit-devtools is a skill published in the GitHub repository Tabbit-Browser/Tabbit-Devtools-Skill (45 stars, last pushed 3mo ago), licensed MIT. It adds 40 tokens to every session and 1,150 once invoked, about $0.0002 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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