What is mars AGENTS.md?

A set of development instructions for Yazelix's Mars terminal, a command-line application derived from Rio. It describes project workflow, source-code boundaries, validation, and release practices.

Use it when developing Mars features, planning changes with Beads, checking related terminal behavior, updating packaging or documentation, and recording validated changes.

It gives coding agents clear rules for changing Mars while keeping updates small and easier to merge with the upstream project. It also helps distinguish Mars-owned files from inherited code.

How Yazelix/mars configures Codex and OpenCode

Reuse

Borrowing it

Nothing to install: this file belongs to Yazelix/mars. 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/Yazelix/mars/main/AGENTS.md

Clone the repo

git clone --depth 1 https://github.com/Yazelix/mars

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/yazelix/mars/agents-md/github.svg)](https://agentmods.dev/instructions/yazelix/mars/agents-md)

Your own site

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

Per session 510 This file is loaded in full into every session.

When invoked 510 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	$0.00510	$0.00510
Opus 5.5	$0.00204	$0.00204
Sonnet 5.5	$0.00102	$0.00102
Haiku 4.5	$0.00051	$0.00051

Measured 2mo ago against content hash fffdc75e0ab7, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

mars 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 · 53 lines

How it starts

The opening of the file, as written. The whole thing — 53 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Mars Agent Guide

Mars is a Rio-derived terminal fork maintained for Yazelix and agent-driven development. Keep changes small, measured, and easy to rebase against upstream Rio.

Workflow

Use br for Beads planning in this repository
Plan behavior work in Beads before editing Rio-owned source
Prefer additive Mars-owned files over broad Rio source rewrites
Keep each feature small, measurable, and easy to remove or upstream
Compare relevant Ghostty and WezTerm behavior before terminal-behavior edits
Search Rio issues and current upstream Rio commits before local Rio-owned source changes
Record Mars-owned code or runtime-behavior commits in docs/yazelix/change_scorecard.md
Preserve normal non-Nix packaging routes where practical, but avoid public support claims until each path is validated

Source Boundaries

Rio-owned source includes the inherited crates and frontend/backend terminal code
Mars-owned surfaces include pkgMars.nix, flake.nix, misc/mars.desktop, tools/mars_*, and docs/yazelix/*
Prefer package, wrapper, config, desktop, docs, and tool changes before renderer, PTY, parser, event-loop, or window changes
If a direct Rio-owned source edit is smaller than an abstraction, keep it direct and document why in the Bead or scorecard

Validation

Choose checks proportional to the touched surface:

README/docs only: git diff --check
GitHub workflow changes: actionlint .github/workflows/<file>.yml
Nix package or metadata changes: nix eval --json .#packages.x86_64-linux.mars.passthru.marsPackageMetadata --no-write-lock-file
Mars package changes: nix build .#mars --no-link --print-build-logs
Rust changes: cargo fmt -- --check --color always, cargo clippy --all-targets --all-features, and cargo test --features wgpu

Release Workflow

The release workflow runs for v*.*.* tags and manual dispatch only. Do not re-enable ordinary main push releases unless the GoReleaser Pro and Apple signing secret policy is decided and documented. The release-secrets evaluation is tracked by Bead yzt-c2d.

Read the full file on GitHub · 53 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 · 53 lines · 510 tokens per session scan A fffdc75e0ab7

Subscribe to this mod's changes

mars AGENTS.md is an instructions file published in the GitHub repository Yazelix/mars (25 stars, last pushed 20d ago), licensed MIT. It adds 510 tokens to every session, about $0.0020 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.

GPU Git and workflow Releases Rust mars rio terminal terminal-emulator

mars AGENTS.md next to 6 instructions from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
mars AGENTS.mdYazelix/mars	Instructions file	25	20d ago	MIT	A	510	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

mars: Instructions file for Codex