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.

In plain words
What is it for?
Working on the server, web interface, progressive web app, terminal sessions, AI-agent tabs, and stored configuration or login-session files.
Why use it?
They record important product contracts so changes do not break host isolation, agent interactions, authentication, or mobile use.

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/leask/tabminal/agents-md
Clone the repo
git clone --depth 1 https://github.com/Leask/Tabminal

Made for: Codex, OpenCode.

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. 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 $0.03412 $0.03412
Opus 5 $0.01706 $0.01706
Sonnet 5 $0.00682 $0.00682
Haiku 4.5 $0.00341 $0.00341

Measured 2d ago against content hash 5aaa9bac8a85, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, 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 2d 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.

  1. 2d 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 (384 stars, last pushed 2mo ago), licensed MIT. It adds 3,412 tokens to every session, about $0.0171 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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