What is zenAgent AGENTS.md?

Repository instructions for coding agents working on Zen Agent, a project that controls a browser the user is actively using.

They guide agents on repository commands, file layout, TypeScript style, browser-tab discovery, stable tab identification, and the separation between browser automation and setup tools.

They prevent automated changes from unexpectedly switching windows, tabs, or browser spaces, and require the agent to handle uncertainty explicitly.

How fschrhunt/zenAgent configures Codex and OpenCode

Reuse

Borrowing it

Nothing to install: this file belongs to fschrhunt/zenAgent. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/fschrhunt/zenAgent/main/AGENTS.md

Clone the repo

git clone --depth 1 https://github.com/fschrhunt/zenAgent

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.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/fschrhunt/zenagent/agents-md/github.svg)](https://agentmods.dev/instructions/fschrhunt/zenagent/agents-md)

Your own site

<a href="https://agentmods.dev/instructions/fschrhunt/zenagent/agents-md"><img src="https://agentmods.dev/badge/instructions/fschrhunt/zenagent/agents-md/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.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/fschrhunt/zenagent/agents-md"><img src="https://agentmods.dev/badge/instructions/fschrhunt/zenagent/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 1,276 This file is loaded in full into every session.

When invoked 1,276 The same file — it is already loaded in full.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

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.

Model	Per session	Once invoked
Fable 5.1	$0.01276	$0.01276
Opus 5.5	$0.00510	$0.00510
Sonnet 5.5	$0.00255	$0.00255
Haiku 4.5	$0.00128	$0.00128

Measured 2mo ago against content hash 0b366a96c5c4, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

zenAgent 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 2mo 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 · 113 lines

How it starts

The opening of the file, as written. The whole thing — 113 lines — stays where its author put it; the contents beside it link to each section on GitHub.

AGENTS.md

Working rules for coding agents in this repository. Read .context/todo.md for what to build next and docs/adr/0001-browser-transport.md for why the architecture is what it is.

The product invariants come first

Zen Agent drives a browser the user is actively working in. These are not preferences; a change that breaks one of them is a bug even if every test passes:

Never focus a Zen window, select a tab, or switch the visible Space as a side effect. browsingContext.activate and tabs.update({active: true}) are the two calls that violate this most easily. The spike keeps activate around only as a positive control.
Look before you open. Discover windows, Spaces, and tabs before deciding to create one.
Address tabs by stable ID, never by whichever tab happens to be active.
Keep browser policy in one shared daemon. MCP is the browser automation surface; the CLI is limited to setup, configuration, and diagnostics.
Fail loudly on ambiguity. Return an explicit ambiguity or unsupported-capability error rather than falling back to something that might disturb the browser.
Model what you do not know. Use the Observation<T> three-way known/unknown/unsupported from src/browser/model.ts instead of inventing a value. Selected and focused state is observable only when the privileged transport reports the corresponding named capability; otherwise it must remain an Observation of unknown or unsupported.
Keep page content out of logs by default — URLs, titles, form values, cookies, and tokens included.

Commands

npm run check          # format:check, lint, typecheck, test, build — the CI gate
npm test               # vitest, no browser required
npm run dev -- --help  # run the CLI from source via tsx
npm run build          # tsc to dist/

npm run check is exactly what CI runs. Run it before opening a pull request.

Read the full file on GitHub · 113 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.

2mo ago First seen · 113 lines · 1,276 tokens per session scan A 0b366a96c5c4

Subscribe to this mod's changes

zenAgent AGENTS.md is an instructions file published in the GitHub repository fschrhunt/zenAgent (0 stars, last pushed 2mo ago), licensed MIT. It adds 1,276 tokens to every session, about $0.0051 per session on Opus 5.5. 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 2026-08-31.

zenAgent AGENTS.md next to 6 instructions from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
zenAgent AGENTS.mdfschrhunt/zenAgent	Instructions file	0	2mo ago	MIT	A	1,276	Codex, OpenCode
vscode buildNext.instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	9,719	GitHub Copilot
next.js AGENTS.mdvercel/next.js	Instructions file	143k	yesterday	MIT	A	7,461	Codex, OpenCode
langchain AGENTS.mdlangchain-ai/langchain	Instructions file	149k	yesterday	MIT	A	4,680	Codex, OpenCode
vscode oss-third-party-notices.instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	5,516	GitHub Copilot
vscode copilot-instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	3,093	GitHub Copilot
deepseek-harness AGENTS.mddeepseek-ai/deepseek-harness	Instructions file	274k	2d ago	MIT	A	4,313	Codex, OpenCode

zenAgent: Instructions file for Codex