agentmods.dev

Vesta: Instructions file for Codex

AGENTS.md

Vesta AGENTS.md is an instructions file for Codex, OpenCode from vestaterm/Vesta. It costs 1,229 tokens per session, scanned A, original, MIT.

A set of instructions for AI agents working on Vesta, a native macOS terminal application built with Swift and AppKit.

In plain words
What is it for?
Use it when modifying Vesta's source code, building the application, running tests, or preparing a release build.
Why use it?
It gives agents the project's rules, build process, architecture, and release checks so their changes fit the existing codebase.

Instructions file for CodexOpenCode

Written for Codex and OpenCode: the file is AGENTS.md. Also seen: mentions AGENTS.md.

This is vestaterm/Vesta's own configuration. It tells Codex and OpenCode how to work on Vesta itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything Vesta configures →

not rated 24repo 2mo ago A scan 1,229 tokens original MIT
View source ↗ vestaterm/Vesta vestaterm.github.io
Reuse

Borrowing it

Nothing to install: this file belongs to vestaterm/Vesta. 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/vestaterm/Vesta/main/AGENTS.md
Clone the repo
git clone --depth 1 https://github.com/vestaterm/Vesta

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.

agentmods badge for Vesta AGENTS.md

README.md
[![agentmods](https://agentmods.dev/badge/instructions/vestaterm/vesta/agents-md/github.svg)](https://agentmods.dev/instructions/vestaterm/vesta/agents-md)
Your own site
<a href="https://agentmods.dev/instructions/vestaterm/vesta/agents-md"><img src="https://agentmods.dev/badge/instructions/vestaterm/vesta/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.

agentmods 80×15 button for Vesta AGENTS.md

Your own site · 80×15
<a href="https://agentmods.dev/instructions/vestaterm/vesta/agents-md"><img src="https://agentmods.dev/badge/instructions/vestaterm/vesta/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 1,229 This file is loaded in full into every session.
When invoked 1,229 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.01229 $0.01229
Opus 5.5 $0.00492 $0.00492
Sonnet 5.5 $0.00246 $0.00246
Haiku 4.5 $0.00123 $0.00123

Measured 2mo ago against content hash f39441cd686c, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

Vesta 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 · 90 lines

How it starts

The opening of the file, as written. The whole thing — 90 lines — stays where its author put it; the contents beside it link to each section on GitHub.

AGENTS.md — rules for AI agents working in Vesta

Vesta is a native macOS terminal built on libghostty (linked as GhosttyKit.xcframework, not a fork), with a project sidebar, tmux-style splits, a persistent-session daemon, embedded Lua plugins, and a scriptable vesta CLI. Swift/AppKit. Bundle id io.github.notnaki.vesta.

Read this before changing anything. Follow it.

Golden rules

  1. Match the surrounding code. Comment density, naming, and idioms vary by file — imitate the file you're editing. Don't reformat code you didn't change.
  2. Minimal diffs (ponytail). Ship the smallest change that works. No speculative abstractions, no scaffolding "for later", delete before adding. Mark deliberate shortcuts with a ponytail: comment.
  3. Never hardcode the version. It's stamped from the git tag by make-app.sh. Read Updater.currentVersion (or CFBundleShortVersionString) — see the past bug where About/sidebar showed a stale 0.1.0.
  4. Verify against a RELEASE build, not just swift run. Several bugs only appeared in the signed/notarized bundle (resource lookup, release-only assert elision). When in doubt, ./make-app.sh release and run the bundle.

Build / run / test

swift build                                   # fetches GhosttyKit automatically
swift run vesta selfcheck                     # pure-logic checks — MUST pass before commit
./make-app.sh [release|debug]                 # build Vesta.app (stamps version/build/commit)
open Vesta.app
  • selfcheck is the test harness — add an assertion there for non-trivial logic. It also fails loudly if bundled resources (fonts) can't be found.
  • assert(...) is compiled out in release. Never put a side-effecting call inside assert(...) — hoist the call out, assert on the result.

Architecture (where things live, all under Sources/)

  • Vesta/main.swift — AppDelegate, app lifecycle, ⌘ keybinds, Lua bridge, toasts/notifications, onboarding + update wiring.
  • Vesta/Chrome.swift — window, titlebar accessories, sidebar (incl. the update badge + version footer).
  • Vesta/Control.swift — the vesta CLI verbs + the Unix-socket server.
  • Vesta/Tabs.swift — SessionStore (app-owned pool) + Workspace (per-window view).
  • Vesta/Updater.swift — in-app self-update (download DMG → swap → relaunch).
  • Vesta/Notifier.swift, AboutWindow.swift, OnboardingOverlay.swift — self-named.
  • vestad/ — the session daemon (one forkpty'd shell per pane + raw output ring).
  • vesta-attach/ — the per-pane relay ghostty spawns; dumb byte pump over a 0600 socket.
  • VestaMux/ — shared wire protocol (MuxProtocol) + paths (MuxPaths).

Read the full file on GitHub · 90 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. 2mo ago First seen · 90 lines · 1,229 tokens per session scan A f39441cd686c

Subscribe to this mod's changes

Vesta AGENTS.md is an instructions file published in the GitHub repository vestaterm/Vesta (24 stars, last pushed 2mo ago), licensed MIT. It adds 1,229 tokens to every session, about $0.0049 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.

Kotlin and SwiftLanguagesai-agentsappkitdeveloper-toolsghosttyluamacos
Related

Vesta AGENTS.md compared with instructions from other repositories

Vesta AGENTS.md next to 6 instructions from other repositories
ModTypeStarsLast pushLicenceScanTokensWorks with
Vesta AGENTS.mdvestaterm/VestaInstructions file242mo agoMITA1,229Codex, OpenCode
vscode buildNext.instructions.mdmicrosoft/vscodeInstructions file195kyesterdayMITA9,719GitHub Copilot
next.js AGENTS.mdvercel/next.jsInstructions file143kyesterdayMITA7,461Codex, OpenCode
langchain AGENTS.mdlangchain-ai/langchainInstructions file149kyesterdayMITA4,680Codex, OpenCode
vscode oss-third-party-notices.instructions.mdmicrosoft/vscodeInstructions file195kyesterdayMITA5,516GitHub Copilot
vscode copilot-instructions.mdmicrosoft/vscodeInstructions file195kyesterdayMITA3,093GitHub Copilot
deepseek-harness AGENTS.mddeepseek-ai/deepseek-harnessInstructions file274k2d agoMITA4,313Codex, OpenCode