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 dkmqflx/nestjs-best-practices-plugin --skill nestjs-interceptorsgit clone --depth 1 https://github.com/dkmqflx/nestjs-best-practices-pluginWrote 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/dkmqflx/nestjs-best-practices-plugin/nestjs-interceptors)<a href="https://agentmods.dev/skills/dkmqflx/nestjs-best-practices-plugin/nestjs-interceptors"><img src="https://agentmods.dev/badge/skills/dkmqflx/nestjs-best-practices-plugin/nestjs-interceptors/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/dkmqflx/nestjs-best-practices-plugin/nestjs-interceptors"><img src="https://agentmods.dev/badge/skills/dkmqflx/nestjs-best-practices-plugin/nestjs-interceptors.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 | $0.00053 | $0.00604 |
| Opus 5 | $0.00026 | $0.00302 |
| Sonnet 5 | $0.00011 | $0.00121 |
| Haiku 4.5 | $0.00005 | $0.00060 |
Grade A, and why
nestjs-interceptors 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 10d 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 — 52 lines — stays where its author put it; the contents beside it link to each section on GitHub.
NestJS Interceptors
Interceptors are @Injectable() classes implementing NestInterceptor. Their
intercept(context: ExecutionContext, next: CallHandler) method runs logic
before the route handler and transforms the response stream returned by
next.handle() using RxJS operators. They are the idiomatic place for
cross-cutting concerns — response shaping, logging, timeouts, caching — that
should stay out of controllers and services.
When to Apply
Apply these rules when you are:
- Writing or reviewing a class that implements
NestInterceptor. - Wrapping handler responses in a consistent envelope.
- Adding request/response logging or latency measurement.
- Enforcing per-request timeouts.
- Caching GET responses with
CacheInterceptor. - Deciding whether to bind an interceptor globally, per-controller, or per-route.
Do not reach for an interceptor when the work is core business logic — that
belongs in a service (see interceptors-not-for-mutation-logic).
Rules
| Rule | Impact | Summary |
|---|---|---|
| response-transform-interceptor | HIGH | Wrap responses in a consistent envelope via map(). |
| logging-interceptor | MEDIUM | Measure handler duration with tap(); log method/url/time. |
| timeout-interceptor | HIGH | Fail slow requests with timeout() + RequestTimeoutException. |
| cache-interceptor | MEDIUM | Cache GET responses with CacheInterceptor + CacheModule. |
| interceptors-not-for-mutation-logic | HIGH | Keep business logic in services; interceptors are cross-cutting only. |
| bind-globally-vs-scoped | MEDIUM | Prefer APP_INTERCEPTOR for DI-friendly global binding. |
How to Use
- Identify the cross-cutting concern (transform, log, timeout, cache).
- Open the matching rule file and follow the Correct pattern.
- Keep
intercept()thin — pipe RxJS operators ontonext.handle(), never put domain logic inside. - Choose a binding scope with
bind-globally-vs-scoped: route, controller, or global viaAPP_INTERCEPTOR.
What ships with it
6 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.
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.
- 10d ago First seen · 52 lines · 53 tokens per session scan A 1aab0a98977c
nestjs-interceptors is a skill published in the GitHub repository dkmqflx/nestjs-best-practices-plugin (1 stars, last pushed 2mo ago), licensed MIT. It adds 53 tokens to every session and 604 once invoked, about $0.0003 per session on Opus 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.
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