Varlock is a configuration system for environment-variable files that gives coding agents schemas and validation rules without revealing secret values. Developers use it to manage, validate, load, and protect application configuration across environments.
Borrowing it
Nothing to install: this file belongs to dmno-dev/varlock. 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/dmno-dev/varlock/main/.github/copilot-instructions.mdgit clone --depth 1 https://github.com/dmno-dev/varlockWrote 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/dmno-dev/varlock/copilot-instructions)<a href="https://agentmods.dev/instructions/dmno-dev/varlock/copilot-instructions"><img src="https://agentmods.dev/badge/instructions/dmno-dev/varlock/copilot-instructions/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/dmno-dev/varlock/copilot-instructions"><img src="https://agentmods.dev/badge/instructions/dmno-dev/varlock/copilot-instructions.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 | $0.00474 | $0.00474 |
| Opus 5.5 | $0.00190 | $0.00190 |
| Sonnet 5.5 | $0.00095 | $0.00095 |
| Haiku 4.5 | $0.00047 | $0.00047 |
Grade A, and why
varlock copilot-instructions.md scanned grade A 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 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.
Runs shell commandslowCapability
Expected in a hook, worth knowing in a rule or an instructions file.
6. **Risky APIs:** Flag unsafe `child_process`, `vm`, or deserialization from untrusted data. How it starts
The opening of the file, as written. The whole thing — 36 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Copilot PR code review (security)
Scope: Focus on code security. Copilot does not review dependency manifests or lockfiles; rely on Dependabot, CodeQL, and the dependency-review workflow for supply chain.
Security checklist (changed lines)
- Secrets: No hardcoded API keys, tokens, passwords, or private URLs. Preserve redaction and leak prevention for sensitive env values.
- Injection / parsing: Safe handling of user-controlled strings in @env-spec parsing and loaders; avoid
eval/new Functionon untrusted input. - Process execution:
exec/spawn/ shell (secret plugins, integrations): avoid shell injection; validate arguments; no untrusted paths. - Filesystem: No path traversal or arbitrary read/write from external input.
- Trust boundaries: Document what untrusted config can do; avoid unsafe defaults.
- Risky APIs: Flag unsafe
child_process,vm, or deserialization from untrusted data. - Crypto: Prefer standard libraries; avoid ad-hoc cryptography.
- AI safety: No prompt injection or other unsafe patterns that might allow exfiltration of secrets.
Varlock: Loaders, CLI, packages/plugins, and MCP integrations are high impact.
Copilot Instructions for Varlock
Varlock adds declarative schema to .env files using @env-spec decorator comments — validation, coercion, type safety, redaction/leak prevention for sensitive values, and multi-environment management.
All project conventions live in AGENTS.md — repo structure, bun/workspace usage, scripts, testing, versioning (bumpy changesets), linting, and branch/PR rules. Follow it.
Quick reference:
bun install # install dependencies
bun run build:libs # build all libraries (excludes website)
bun run test:ci # run tests once (CI mode)
bun run lint:fix # lint with auto-fix — run before completing any task
Before finishing any task: run bun run lint:fix, verify bun run build:libs passes, and add a bumpy changeset if publishable packages changed (see AGENTS.md for details).
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 First seen · 36 lines · 474 tokens per session scan A 10334e17e52e
varlock copilot-instructions.md is an instructions file published in the GitHub repository dmno-dev/varlock (4,830 stars, last pushed 5d ago), licensed MIT. It adds 474 tokens to every session, about $0.0019 per session on Opus 5.5. A static security scan graded it A with 1 finding (runs shell commands). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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