Borrowing it
Nothing to install: this file belongs to unjs/std-env. 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/unjs/std-env/main/AGENTS.mdgit clone --depth 1 https://github.com/unjs/std-envWrote 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/unjs/std-env/agents-md)<a href="https://agentmods.dev/instructions/unjs/std-env/agents-md"><img src="https://agentmods.dev/badge/instructions/unjs/std-env/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/unjs/std-env/agents-md"><img src="https://agentmods.dev/badge/instructions/unjs/std-env/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 | $0.02417 | $0.02417 |
| Opus 5.5 | $0.00967 | $0.00967 |
| Sonnet 5.5 | $0.00483 | $0.00483 |
| Haiku 4.5 | $0.00242 | $0.00242 |
Grade A, and why
std-env 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 1mo 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 — 151 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Agents
Project Overview
std-env — runtime-agnostic JS utility library for detecting environments, runtimes, CI providers, and AI coding agents. Published as std-env on npm under unjs/std-env.
Maintenance
AGENTS.md— Keep updated with technical details, architecture, and conventions for AI agents working on this projectREADME.md— Keep updated with user-facing documentation (usage, installation, exported APIs, examples)
When adding new features or changing behavior, update both files accordingly.
After finishing any code updates, always run pnpm lint:fix then pnpm test to auto-fix lint/formatting issues and verify everything passes.
- ESM-only (
"type": "module", single.mjsoutput) - Linted with
oxlint+oxfmt, typechecked withtsgo - Tested with
vitest - Built with
obuild
Scripts
| Script | Description |
|---|---|
pnpm run build |
Build with obuild (dist/index.mjs, dist/index.d.mts) |
pnpm run dev |
Start vitest in watch mode |
pnpm run test |
Lint + typecheck + vitest with coverage |
pnpm run lint |
Run oxlint and oxfmt |
pnpm run lint:fix |
Auto-fix lint/format issues |
pnpm run typecheck |
Run tsgo --noEmit |
Source Structure
All source lives in src/, single entry point at src/index.ts which re-exports everything.
| File | Purpose |
|---|---|
src/index.ts |
Barrel re-export of all modules |
src/agents.ts |
AI coding agent detection (detectAgent, agentInfo, agent, isAgent) |
src/providers.ts |
CI/CD provider detection (detectProvider, providerInfo, provider) |
src/runtimes.ts |
JS runtime detection (runtime, runtimeInfo, isNode, isBun, isDeno, etc.) |
src/flags.ts |
Environment flags (isCI, isDebug, isTest, isProduction, isDevelopment, isMinimal, platform, etc.) |
src/env.ts |
Universal env proxy + nodeENV constant |
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.
- 1mo ago Changed · +4 lines · +229 tokens per session d1638861d0bb
- 2mo ago First seen · 147 lines · 2,188 tokens per session scan A 91048081a5a7
std-env AGENTS.md is an instructions file published in the GitHub repository unjs/std-env (646 stars, last pushed today), licensed MIT. It adds 2,417 tokens to every session, about $0.0097 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.
std-env AGENTS.md compared with instructions from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| std-env AGENTS.mdunjs/std-env | Instructions file | 646 | today | MIT | A | 2,417 | 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 | today | 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 |