What is Tabminal AGENTS.md?

Repository instructions for Tabminal, a Node.js web application with persistent terminal sessions, AI assistants, and a workspace that can connect to multiple hosts.

Working on the server, web interface, progressive web app, terminal sessions, AI-agent tabs, and stored configuration or login-session files.

They record important product contracts so changes do not break host isolation, agent interactions, authentication, or mobile use.

How Leask/Tabminal configures Codex and OpenCode

Reuse

Borrowing it

Nothing to install: this file belongs to Leask/Tabminal. 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/Leask/Tabminal/main/AGENTS.md

Clone the repo

git clone --depth 1 https://github.com/Leask/Tabminal

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/leask/tabminal/agents-md/github.svg)](https://agentmods.dev/instructions/leask/tabminal/agents-md)

Your own site

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

Per session 3,412 This file is loaded in full into every session.

When invoked 3,412 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	$0.03412	$0.03412
Opus 5.5	$0.01365	$0.01365
Sonnet 5.5	$0.00682	$0.00682
Haiku 4.5	$0.00341	$0.00341

Measured 2mo ago against content hash 5aaa9bac8a85, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

Tabminal 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 · 483 lines

How it starts

The opening of the file, as written. The whole thing — 483 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Tabminal Agent Notes

Last updated: 2026-03-27

This file is for future coding agents working in this repo. Keep it current, specific, and operational. The main goal is to preserve the current product contracts so later work does not regress multi-host behavior, ACP agent UX, or mobile ergonomics.

1) Project Snapshot

Runtime: Node.js >= 22, ESM project.
Backend entry: src/server.mjs
Frontend entry: public/app.js
PWA shell:
- public/index.html
- public/sw.js
Native app workspace:
- apps/Apple
- apps/ghostty-vendor

Current product shape:

Persistent terminal sessions remain the core product.
There are now two AI surfaces:
- terminal-native assistant in src/terminal-session.mjs
- ACP agent workspace in src/acp-manager.mjs + public/app.js
One web UI can connect to multiple Tabminal hosts.
The workspace bar now mixes file tabs, agent tabs, and pinned terminal tabs.

Important persistence files under ~/.tabminal:

config.json
cluster.json
agent-tabs.json
agent-config.json
auth-sessions.json

2) Non-Negotiable Contracts

2.1 Host model and state isolation

UI term is Host, not Server, for user-facing labels.
Every session belongs to exactly one host.
Session state, editor state, file tree state, ACP agent tabs, and workspace tabs are host-isolated.
Do not merge runtime state across hosts.

Relevant code:

public/app.js
public/modules/session-meta.js

2.2 Auth model

Main host (id = 'main') controls the global login modal.
Only main-host 401/403 should trigger app-wide login UI.
Sub-host auth failures must stay local to that host.
Sub-hosts may require Cloudflare Access login without password change.

Relevant code:

public/app.js
- ServerClient.handleUnauthorized
- ServerClient.handleAccessRedirect

2.3 Token storage

Auth state is browser-owned.
All hosts persist auth state in browser localStorage.
Key format:
- tabminal_auth_state:<hostId>
Stored auth state currently includes:
- short-lived access token
- access token expiry
- refresh token
- refresh token expiry
Legacy password-hash token storage is no longer supported or migrated.
Removing a host should also remove any stale local auth state keyed to that host.

Read the full file on GitHub · 483 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 · 483 lines · 3,412 tokens per session scan A 5aaa9bac8a85

Subscribe to this mod's changes

Tabminal AGENTS.md is an instructions file published in the GitHub repository Leask/Tabminal (392 stars, last pushed 14d ago), licensed MIT. It adds 3,412 tokens to every session, about $0.0136 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 2026-08-30.

Tabminal AGENTS.md next to 6 instructions from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
Tabminal AGENTS.mdLeask/Tabminal	Instructions file	392	14d ago	MIT	A	3,412	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

Tabminal: Instructions file for Codex