Borrowing it
Nothing to install: this file belongs to burin-labs/harn. 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/burin-labs/harn/main/AGENTS.mdgit clone --depth 1 https://github.com/burin-labs/harnWrote 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/burin-labs/harn/agents-md)<a href="https://agentmods.dev/instructions/burin-labs/harn/agents-md"><img src="https://agentmods.dev/badge/instructions/burin-labs/harn/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.
<a href="https://agentmods.dev/instructions/burin-labs/harn/agents-md"><img src="https://agentmods.dev/badge/instructions/burin-labs/harn/agents-md.svg" alt="Reviewed on agentmods" width="80" 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 | $0.04228 | $0.04228 |
| Opus 5.5 | $0.01691 | $0.01691 |
| Sonnet 5.5 | $0.00846 | $0.00846 |
| Haiku 4.5 | $0.00423 | $0.00423 |
Grade A, and why
harn 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 3d 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 — 309 lines — stays where its author put it; the contents beside it link to each section on GitHub.
AGENTS.md
Harn is a programming language and runtime for orchestrating AI agents.
This file is the repository contract for Codex, Claude, and other coding
agents. CLAUDE.md must remain a symlink to it. The durable design principles
live in Engineering principles:
- ambitious outcomes behind boring seams;
- one owner with many projections;
- structure over prose;
- evidence matched to claims;
- canonical paths;
- controllable autonomy;
- cross-surface convergence;
- operationally complete launches.
Ownership
- Harn owns orchestration, transcript lifecycle, replay/eval, delegated-worker lineage, capability policy, and mutation-session audit metadata.
- Hosts own native presentation, approval UX, concrete file mutations, and undo/redo semantics.
- Prefer the Harn runtime and stdlib over new host glue.
- A semantic decision has one owner. CLI, TUI, IDE, headless, and cloud behavior should be projections or adapters, not parallel implementations.
- Prefer deep modules: small interfaces that hide substantial behavior.
- Make contracts structural with types, registries, events, generated projections, and drift checks. Prose should explain the contract, not enforce it.
Working agreement
- Research, implement, verify, recover, and ship autonomously inside the approved scope.
- Pause for genuine ambiguity, destructive or out-of-scope action, production impact, exceptional spend, or new authority—not routine reversible work.
- Treat stop, wait, stand down, and pivot as control events. Do not continue stale work after one arrives.
- Start from the claim and name a plausible falsifier. Match evidence to the claim; test counts alone are not proof.
- Exercise the canonical user path for product claims and progress, interruption, recovery, and terminal state for liveness claims.
- Use multiple trials and calibrated graders for stochastic quality claims.
- "Ship" means landed on the intended main branch with required post-merge or release checks complete.
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.
- 3d ago Changed · +4 lines · +72 tokens per session bedaf7dfea1f
- 4d ago Changed · -8 tokens per session ec349d2a2d71
- 5d ago Changed · -5 tokens per session a98c5f176f48
- 7d ago Changed · +2 lines · +31 tokens per session 5b6b38dde2ef
- 15d ago Changed · +2 lines · +40 tokens per session 24d1661ea692
- 16d ago Changed · +1 lines · +32 tokens per session 78f662b51a8e
- 18d ago Changed · +7 lines · +118 tokens per session bc8cae75c8f9
- 19d ago Changed · -11 lines · -176 tokens per session 7a3decd9a19e
- 20d ago Changed · +8 lines · +148 tokens per session 32a5ac8f7b80
- 23d ago First seen · 296 lines · 3,976 tokens per session scan A c0220e7a3d12
harn AGENTS.md is an instructions file published in the GitHub repository burin-labs/harn (28 stars, last pushed today), licensed Apache-2.0. It adds 4,228 tokens to every session, about $0.0169 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.
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).
next.js AGENTS.md
AGENTS.md instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.
vscode oss-third-party-notices.instructions.md
Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, cache eligibility and rollout and applying the notice (cutover).
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 copilot-instructions.md
Copilot instructions for microsoft/vscode, covering vs code copilot instructions, project overview, root folders, core architecture (src/ folder) and built-in extensions (extensions/ folder).
deno copilot-instructions.md
Copilot instructions for denoland/deno, covering deno development guide for github copilot, network access, high level overview, key directories and key files to understand first.