Borrowing it
Nothing to install: this file belongs to mishahanin/heading-os. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/mishahanin/heading-os/main/CLAUDE.mdgit clone --depth 1 https://github.com/mishahanin/heading-osWrote 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/mishahanin/heading-os/claude-md)<a href="https://agentmods.dev/instructions/mishahanin/heading-os/claude-md"><img src="https://agentmods.dev/badge/instructions/mishahanin/heading-os/claude-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 5.1 | $0.03077 | $0.03077 |
| Opus 5 | $0.01538 | $0.01538 |
| Sonnet 5 | $0.00615 | $0.00615 |
| Haiku 4.5 | $0.00308 | $0.00308 |
Grade C, and why
heading-os CLAUDE.md scanned grade C with 1 finding 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 today.
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.
Hidden instructionshighPrompt injection
Directives inside HTML comments, invisible characters or bidirectional overrides are read by the model and not by the person reviewing the file.
<!-- Deliberately the LAST thing in the rendered system prompt. Anthropic's Opus 5 prompt-engineering guidance: effort does not reliably shorten a visible response, so length is controlled by an explicit instruction, and How it starts
The opening of the file, as written. The whole thing — 211 lines — stays where its author put it; the contents beside it link to each section on GitHub.
CLAUDE.md — HEADING OS Engine
HEADING OS is an operations engine for an AI executive assistant: a library of skills, always-on rules, automation scripts, and daemons that let Claude Code act as a strategic assistant across sessions. This repository is the engine — code only, no private data. It is a personal project built and maintained by Misha Hanin and shared as an open framework. Misha is the Founder & CEO of 31 Concept (31C) and uses HEADING OS himself, but 31 Concept is not involved in it and bears no responsibility for it; any 31C-like vocabulary here is illustrative example data only.
Engine / data separation
The engine never contains real data, secrets, or PII. Anything
operator-specific — contacts, knowledge, outputs, threads, real identities,
credentials — lives outside this repo: in a separate private data overlay and in
gitignored runtime files (.env, .sessions). Routing is declared in
config/routing-map.yaml and enforced by scripts/leak-guard.py,
scripts/utils/engine_guard.py, and the unbypassable push-time content scan in
scripts/push-all.py.
If you run this as your own operator workspace, your private operational notes
load from a local overlay via the import at the bottom of this file; on a public
clone that overlay is simply absent and the engine runs on its defaults and
*.example.* templates.
Layout
.claude/skills/— skills (one folder per skill:SKILL.md, optionalreferences/,triggers.json).claude/rules/— always-on and path-scoped behavioral rulesscripts/— CLI utilities and daemons; shared modules inscripts/utils/tests/— pytest suiteconfig/— engine configuration (real instance values stay private); the*.example.*per-instance templates live beside the scripts that read them, inscripts/docs/,reference/,examples/— documentation and scaffolding
Setup
Canonical toolchain is uv; pyproject.toml is the source of truth and uv.lock
pins the resolved set.
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.
- today Changed 70cf0334dd98
- 2d ago Changed · +31 lines · +623 tokens per session 850244147bb3
- 3d ago Changed · +39 lines · +591 tokens per session 2f737ffc5974
- 4d ago First seen · 141 lines · 1,863 tokens per session scan C e60d2756ef74
heading-os CLAUDE.md is an instructions file published in the GitHub repository mishahanin/heading-os (11 stars, last pushed yesterday), licensed Apache-2.0. It adds 3,077 tokens to every session, about $0.0154 per session on Opus 5. A static security scan graded it C with 1 finding (hidden instructions). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.
Other instructions, from other repositories
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AGENTS.md instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.
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AGENTS.md instructions for openai/codex, covering rust/codex-rs, the codex-core crate, code review rules, crate api surface and model visible context.
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).
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).
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.
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.