Borrowing it
Nothing to install: this file belongs to CobaltBlue3699/mysql-mcp-server. 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/CobaltBlue3699/mysql-mcp-server/main/.agents/skills/nestjs-best-practices/SKILL.mdgit clone --depth 1 https://github.com/CobaltBlue3699/mysql-mcp-serverWrote 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/skills/cobaltblue3699/mysql-mcp-server/nestjs-best-practices)<a href="https://agentmods.dev/skills/cobaltblue3699/mysql-mcp-server/nestjs-best-practices"><img src="https://agentmods.dev/badge/skills/cobaltblue3699/mysql-mcp-server/nestjs-best-practices/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/skills/cobaltblue3699/mysql-mcp-server/nestjs-best-practices"><img src="https://agentmods.dev/badge/skills/cobaltblue3699/mysql-mcp-server/nestjs-best-practices.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 | $0.00050 | $0.01142 |
| Opus 5 | $0.00025 | $0.00571 |
| Sonnet 5 | $0.00010 | $0.00228 |
| Haiku 4.5 | $0.00005 | $0.00114 |
Grade A, and why
nestjs-best-practices 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 11d 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.
This is a copy
100% identical to nestjs-best-practices — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 131 lines — stays where its author put it; the contents beside it link to each section on GitHub.
NestJS Best Practices
Comprehensive best practices guide for NestJS applications. Contains 40 rules across 10 categories, prioritized by impact to guide automated refactoring and code generation.
When to Apply
Reference these guidelines when:
- Writing new NestJS modules, controllers, or services
- Implementing authentication and authorization
- Reviewing code for architecture and security issues
- Refactoring existing NestJS codebases
- Optimizing performance or database queries
- Building microservices architectures
Rule Categories by Priority
| Priority | Category | Impact | Prefix |
|---|---|---|---|
| 1 | Architecture | CRITICAL | arch- |
| 2 | Dependency Injection | CRITICAL | di- |
| 3 | Error Handling | HIGH | error- |
| 4 | Security | HIGH | security- |
| 5 | Performance | HIGH | perf- |
| 6 | Testing | MEDIUM-HIGH | test- |
| 7 | Database & ORM | MEDIUM-HIGH | db- |
| 8 | API Design | MEDIUM | api- |
| 9 | Microservices | MEDIUM | micro- |
| 10 | DevOps & Deployment | LOW-MEDIUM | devops- |
Quick Reference
1. Architecture (CRITICAL)
arch-avoid-circular-deps- Avoid circular module dependenciesarch-feature-modules- Organize by feature, not technical layerarch-module-sharing- Proper module exports/imports, avoid duplicate providersarch-single-responsibility- Focused services over "god services"arch-use-repository-pattern- Abstract database logic for testabilityarch-use-events- Event-driven architecture for decoupling
2. Dependency Injection (CRITICAL)
di-avoid-service-locator- Avoid service locator anti-patterndi-interface-segregation- Interface Segregation Principle (ISP)di-liskov-substitution- Liskov Substitution Principle (LSP)di-prefer-constructor-injection- Constructor over property injectiondi-scope-awareness- Understand singleton/request/transient scopesdi-use-interfaces-tokens- Use injection tokens for interfaces
What ships with it
48 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
- AGENTS.md 159 KB
- README.md 4.4 KB
- rules/_sections.md 2.1 KB
- rules/_template.md 631 B
- rules/api-use-dto-serialization.md 4.3 KB
- rules/api-use-interceptors.md 5.4 KB
- rules/api-use-pipes.md 5.3 KB
- rules/api-versioning.md 4.9 KB
- rules/arch-avoid-circular-deps.md 2.0 KB
- rules/arch-feature-modules.md 2.3 KB
- rules/arch-module-sharing.md 3.8 KB
- rules/arch-single-responsibility.md 2.9 KB
- rules/arch-use-events.md 3.0 KB
- rules/arch-use-repository-pattern.md 2.8 KB
- rules/db-avoid-n-plus-one.md 3.8 KB
- rules/db-use-migrations.md 3.7 KB
- rules/db-use-transactions.md 3.9 KB
- rules/devops-graceful-shutdown.md 5.8 KB
- rules/devops-use-config-module.md 4.3 KB
- rules/devops-use-logging.md 5.6 KB
- rules/di-avoid-service-locator.md 2.9 KB
- rules/di-interface-segregation.md 5.1 KB
- rules/di-liskov-substitution.md 7.1 KB
- rules/di-prefer-constructor-injection.md 2.3 KB
- rules/di-scope-awareness.md 2.6 KB
- rules/di-use-interfaces-tokens.md 2.5 KB
- rules/error-handle-async-errors.md 3.4 KB
- rules/error-throw-http-exceptions.md 3.1 KB
- rules/error-use-exception-filters.md 3.6 KB
- rules/micro-use-health-checks.md 5.8 KB
- rules/micro-use-patterns.md 5.0 KB
- rules/micro-use-queues.md 6.1 KB
- rules/perf-async-hooks.md 2.8 KB
- rules/perf-lazy-loading.md 3.7 KB
- rules/perf-optimize-database.md 3.2 KB
- rules/perf-use-caching.md 3.4 KB
- rules/security-auth-jwt.md 4.0 KB
- rules/security-rate-limiting.md 3.2 KB
- rules/security-sanitize-output.md 3.7 KB
- rules/security-use-guards.md 3.6 KB
- rules/security-validate-all-input.md 3.3 KB
- rules/test-e2e-supertest.md 4.7 KB
- rules/test-mock-external-services.md 4.5 KB
- rules/test-use-testing-module.md 4.3 KB
- scripts/build-agents.ts 8.5 KB runs code
- scripts/build.sh 369 B runs code
- scripts/package-lock.json 8.5 KB
- scripts/package.json 428 B
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.
- 11d ago First seen · 131 lines · 50 tokens per session scan A b699d2245ddc
nestjs-best-practices is a skill published in the GitHub repository CobaltBlue3699/mysql-mcp-server (0 stars, last pushed 1mo ago), licensed MIT. It adds 50 tokens to every session and 1,142 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to nestjs-best-practices, differing in 0 lines, and is treated as a copy.
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