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.
npx agentmods add instructions/marcello-a/planchette/agents-mdgit clone --depth 1 https://github.com/marcello-a/PlanchetteWrote 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.
[](https://agentmods.dev/instructions/marcello-a/planchette/agents-md)<a href="https://agentmods.dev/instructions/marcello-a/planchette/agents-md"><img src="https://agentmods.dev/badge/instructions/marcello-a/planchette/agents-md.svg" alt="Measured on agentmods" height="20"></a>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 | $0.02650 | $0.02650 |
| Opus 5 | $0.01325 | $0.01325 |
| Sonnet 5 | $0.00530 | $0.00530 |
| Haiku 4.5 | $0.00265 | $0.00265 |
Grade A, and why
Planchette 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 4d 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.
How it starts
The opening of the file, as written. The whole thing — 166 lines — stays where its author put it; the contents beside it link to each section on GitHub.
AGENTS.md — guide for AI contributors
This file orients an AI (or a new engineer) working in Planchette. Read it before making changes. It complements docs/ARCHITECTURE.md (how the code is structured) and CONTRIBUTING.md (how to build, test, release).
What Planchette is
A native macOS terminal IDE for running many AI coding agents at once, built on the Ghostty engine (libghostty). It shows which session needs attention (asking / done / free), keeps layouts persistent across restart & reboot, and groups terminals by project. See README.md and docs/CONCEPT.md.
Ground rules
- No new external dependencies without asking. The app deliberately links
only Apple frameworks + our self-built
GhosttyKit. The updater uses the GitHub REST API directly instead of Sparkle; AI summaries shell out to the user's existingclaudeCLI instead of an SDK. Keep it that way unless the user explicitly approves a dependency. - libghostty is pinned.
vendor/ghosttyis a submodule fixed to a tag (currently v1.3.1). Its embedding API is not stable across versions — do not bump it casually; a bump is its own reviewed change. - Everything user-facing is localized. Never hardcode a display string.
Add an
LKeycase and a value in all language tables inLocalization.swift(EN is the required fallback — a test enforces it). - State changes go through
AppStateand must be persisted. If you add a persisted field, updatePersistedState(bothinits),saveNow,applyRestore,startFresh, andAppState.init's early load. - A user-facing feature is not done until it is in the Help tab. Every
feature the user can reach appears in
Help.sections(Help.swift), which is what the searchable Help tab in Settings renders. Add the entry in the same change as the feature, reusing theLKeys you already added for the control itself — the catalogue deliberately holds keys, not its own copy of the text, so help cannot drift from the UI. A test walks every entry and fails on an untranslated key. If a feature has no tooltip worth listing, that is a sign the control needs one, not that the feature skips the catalogue. - Keep the main thread free. Subprocess/network work (
claude -p, AppleScript,lsof, GitHub API) runs off-main; only touch@MainActorstate after awaiting back. - Verify by driving the app, not just building. See "Verifying" below.
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.
- 4d ago First seen · 166 lines · 2,650 tokens per session scan A 0256d9d540cf
Planchette AGENTS.md is an instructions file published in the GitHub repository marcello-a/Planchette (3 stars, last pushed 4d ago), licensed MIT. It adds 2,650 tokens to every session, about $0.0132 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 2026-08-31.
Other instructions, from other repositories
vscode buildNext.instructions.md
Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).
spec-kit AGENTS.md
AGENTS.md instructions for github/spec-kit, covering agents.md, about spec kit and specify, quickstart — add a new integration in 5 steps, integration architecture and integrationmanifest — file tracking.
codex AGENTS.md
AGENTS.md instructions for openai/codex, covering rust/codex-rs, the codex-core crate, code review rules, crate api surface and model visible context.
langchain AGENTS.md
AGENTS.md instructions for langchain-ai/langchain, covering global development guidelines for the langchain monorepo, corridor security analysis, project architecture and context, monorepo structure and development tools & commands.
vscode oss-third-party-notices.instructions.md
Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, applying the notice (cutover) and fallback chain (never fail the build).
next.js AGENTS.md
Instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.