Borrowing it
Nothing to install: this file belongs to puristajs/harness. 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/puristajs/harness/main/AGENTS.mdgit clone --depth 1 https://github.com/puristajs/harnessWrote 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/puristajs/harness/agents-md)<a href="https://agentmods.dev/instructions/puristajs/harness/agents-md"><img src="https://agentmods.dev/badge/instructions/puristajs/harness/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/puristajs/harness/agents-md"><img src="https://agentmods.dev/badge/instructions/puristajs/harness/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 | $0.00516 | $0.00516 |
| Opus 5.5 | $0.00206 | $0.00206 |
| Sonnet 5.5 | $0.00103 | $0.00103 |
| Haiku 4.5 | $0.00052 | $0.00052 |
Grade A, and why
harness 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.
How it starts
The opening of the file, as written. The whole thing — 46 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Agent Guidance
This repository defines a self-hosted enterprise agent harness. It is lower-level harness infrastructure, not a SaaS product.
Source of Truth
- Approved specs:
specs/ - Approved readiness gate:
specs/.readiness-report.yaml - Product, architecture, and scope:
specs/00-overview.md,specs/01-architecture.md - Stack and public API:
specs/02-harness-config.md,specs/13-public-api.md - Interfaces and ports:
specs/04-state-queue-stream.md,specs/05-sandbox.md,specs/06-models.md,specs/07-tools.md - Failure handling:
specs/15-error-catalog.md - Test strategy:
specs/16-testing.md - Plans, reviews, and tickets:
plans/(review findings and implementation plans live here, not underdocs/) - Implementation conventions:
.agent/IMPLEMENTATION.md
Use specs/ and plans/ as the only approved definition sources. Historical
review material and previous implementation code are not source of truth.
Repository Rules
- Use npm workspaces for TypeScript packages unless the specs are changed by a human.
- Keep shared harness logic in
packages/. - v1 has no deployable service/workers/apps package; examples under
examples/are private workspaces. - Core harness code depends on ports and contracts, not concrete provider SDKs.
- Adapter packages own provider SDK dependencies and must pass shared contract tests.
- Harness code must not depend on
evals/,k8s/, or repo-localskills/.
Expected Commands
npm run lintnpm run buildnpm testnpm run test:coveragenpm run test:typesnpm run test:contractsnpm run test:integrationnpm run test:failure
Implementation Rules
- Follow each ticket's
write_scopeandread_scope. - Do not invent missing contracts, interfaces, data models, or failure behavior during implementation.
- If a ticket depends on missing definition work, flag it in
specs/.readiness-report.yamlor add a gap report underplans/instead of guessing. - Preserve timeout, retry, idempotency, cleanup, DLQ/manual-intervention, backpressure, and telemetry behavior from specs.
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 · 46 lines · 516 tokens per session scan A baedfe2b291a
harness AGENTS.md is an instructions file published in the GitHub repository puristajs/harness (5 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 516 tokens to every session, about $0.0021 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 2026-08-31.
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).
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.