Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add AmariahAK/atlarix-skills --skill express-fastifygit clone --depth 1 https://github.com/AmariahAK/atlarix-skillsWrote 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/amariahak/atlarix-skills/express-fastify)<a href="https://agentmods.dev/skills/amariahak/atlarix-skills/express-fastify"><img src="https://agentmods.dev/badge/skills/amariahak/atlarix-skills/express-fastify/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/amariahak/atlarix-skills/express-fastify"><img src="https://agentmods.dev/badge/skills/amariahak/atlarix-skills/express-fastify.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 | $0.00006 | $0.00422 |
| Opus 5 | $0.00003 | $0.00211 |
| Sonnet 5 | $0.00001 | $0.00084 |
| Haiku 4.5 | $0.00001 | $0.00042 |
Grade A, and why
Express/Fastify Backend Patterns 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 7d 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.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
- **Debug**: capture full error + stack; reproduce with a single curl/HTTP request. What it actually says
Express/Fastify Backend Patterns
When to use this skill
Use this skill when building Node.js HTTP APIs with Express or Fastify and you want safe request validation, predictable error handling, and maintainable routing/service layering.
Core patterns
Boundary validation
Validate at the edge (request body/params/query):
- reject invalid shapes early
- normalize types (numbers, booleans)
- avoid passing raw request objects into services
Layering
Keep:
- routes/controllers: parsing + HTTP response
- services: business logic
- repositories/adapters: DB/external APIs
Error handling
Rules:
- throw domain errors in services
- map to HTTP status codes in one place (middleware/error handler)
- include request IDs in logs
Timeouts and retries
- apply timeouts to outbound HTTP/DB calls
- retries must be bounded and idempotent
Observability
- structured logs (no secrets)
- basic metrics for request duration/error rates (if available)
Atlarix tool notes
- Explore: locate route registration and middleware order with
grep/glob. - Build: make small edits; run API tests; keep handlers thin.
- Debug: capture full error + stack; reproduce with a single curl/HTTP request.
- Review: check validation, authz, and that errors don’t leak secrets.
Common mistakes to avoid
- No validation (passing raw JSON deep into code)
- Controllers doing business logic
- Swallowing errors in catch blocks
- Missing timeouts on outbound calls
Mini-checklist
- Validation at boundaries
- Centralized error mapping
- Clear layering
- Timeouts on outbound calls
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.
- 7d ago First seen · 61 lines · 6 tokens per session scan A a96065e13963
Express/Fastify Backend Patterns is a skill published in the GitHub repository AmariahAK/atlarix-skills (2 stars, last pushed 3d ago), licensed Apache-2.0. It adds 6 tokens to every session and 422 once invoked, about $0.0000 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.
Other skills, from other repositories
fastify
Production Fastify (TypeScript) patterns: schema validation, plugins, typed routes, error handling, security hardening, logging, testing with inject, and graceful shutdown.
Express.js Testing Patterns
Express.js API testing with supertest, middleware testing, route handler testing, error handling verification, and authentication testing.
backend
Backend development with Node.js, Express, NestJS, and server patterns.
darto-add-route
Add or modify HTTP endpoints in a Darto (Dart) web app — verbs, path/query params, request-body reading, route groups, and Context response helpers. Use when building or changing API routes in a project that depends on the darto package (import 'package:darto/darto.dart'). Not for Express/Node — Darto handlers take a…
darto-validate-request
Validate the body, query, params, or headers of a Darto (Dart) request using the zValidator middleware and zard (Zod-style) schemas. Use when adding input validation to a Darto endpoint, defining a z.map/z.string/z.int schema, reading validated data with c.req.valid, or customizing the validation error response.…
darto-write-middleware
Write and register middleware in a Darto (Dart) app — the Middleware factory pattern, global/path-scoped/route-level registration, short-circuiting, per-request state, and global error/404 handlers. Use when adding cross-cutting behavior (auth, logging, CORS, timing) or configuring app.onError / app.notFound in a…