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 ericrisco/rsc-harness --skill nestjsgit clone --depth 1 https://github.com/ericrisco/rsc-harnessWrote 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/ericrisco/rsc-harness/nestjs)<a href="https://agentmods.dev/skills/ericrisco/rsc-harness/nestjs"><img src="https://agentmods.dev/badge/skills/ericrisco/rsc-harness/nestjs.svg" alt="Measured on agentmods" 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 | $0.00081 | $0.02764 |
| Opus 5 | $0.00041 | $0.01382 |
| Sonnet 5 | $0.00016 | $0.00553 |
| Haiku 4.5 | $0.00008 | $0.00276 |
Grade A, and why
nestjs 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 3d 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 — 218 lines — stays where its author put it; the contents beside it link to each section on GitHub.
NestJS
Build server-side Node apps the way NestJS intends: feature modules, providers wired through the DI container, controllers, and a cross-cutting layer bound at a deliberate scope. This skill is about Nest-specific mechanics — how DI scopes resolve, what order the request lifecycle runs in, where to bind guards/pipes/interceptors/filters, and how to test it with Test.createTestingModule.
Not this — route instead
- Bare Express/Fastify/
httpservice, no@Module/@Injectable→../nodejs/SKILL.md. Nest starts the moment the DI container appears. - REST resource modeling, versioning, status codes, idempotency (framework-agnostic) →
../api-design/SKILL.md. Nest is where you implement those decisions. - Designing the schema / writing queries / migrations →
../prisma-orm/SKILL.md. Injecting a repo orDataSourceprovider stays here; designing the table does not. - Generic JS/TS test infra (Jest config, coverage thresholds, monorepo) →
../testing-web/SKILL.md. The Nest harness (TestingModule,overrideProvider, Supertest bootstrap) stays here.
Mental model
Everything is a provider in a directed DI graph. Modules draw the boundaries of that graph — a provider is only reachable where it is provided or imported. Cross-cutting concerns (guards, interceptors, pipes, filters) are decorators bound at a scope you choose: global, controller, or route. Get those three right and the rest is plumbing.
The request lifecycle runs in a fixed order. Memorize it — most "my guard can't see the validated body" bugs are an ordering misunderstanding:
req → middleware → guards → interceptors(pre) → pipes → handler → interceptors(post) → exception filters → res
So pipes run after guards (a guard cannot read a transformed DTO), and filters catch everything thrown downstream. Source: NestJS request-lifecycle docs.
Module design
One feature module per bounded context. Rules, each with its why:
exportsis the module's public API. A provider not exported is private to that module — that is the encapsulation, lean on it.importsbrings in another module's exports; it does not re-declare providers. Re-declaring a provider in two modules gives you two singletons and silent state bugs.- Keep
AppModulethin. It wires feature modules and global config, nothing else. A godAppModulethat declares every controller becomes an untestable circular-dependency magnet. - Use a dynamic module (
forRoot/forRootAsync) for configurable infrastructure (DB, cache, mailer) so consumers pass options instead of editing the module.
What ships with it
5 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.
- 3d ago First seen · 218 lines · 81 tokens per session scan A 9aedff493c45
nestjs is a skill published in the GitHub repository ericrisco/rsc-harness (65 stars, last pushed yesterday), licensed MIT. It adds 81 tokens to every session and 2,764 once invoked, about $0.0004 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 2026-09-03.
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