explain

A command that explains how a requested part of a NestJS codebase works after reading the relevant source files. NestJS is a framework for building server-side TypeScript applications.

In plain words
What is it for?
Use it to understand request handling, authentication, module wiring, database access, response formatting, or error handling in the codebase.
Why use it?
It grounds the explanation in the project's actual implementation instead of relying only on general framework knowledge.

Command for Claude Code

Install

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.

agentmods
npx agentmods add commands/hmake98/nestjs-starter/explain
Clone the repo
git clone --depth 1 https://github.com/hmake98/nestjs-starter

Made for: Claude Code.

Per session 0 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 476 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00000 $0.00476
Opus 5 $0.00000 $0.00238
Sonnet 5 $0.00000 $0.00095
Haiku 4.5 $0.00000 $0.00048

Measured 2d ago against content hash dc51b6d5df18, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

explain 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 2d 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.

.claude/commands/explain.md · 26 lines

What it actually says

Explain how the following works in this NestJS codebase: $ARGUMENTS

Before answering, read the relevant source files so your explanation is grounded in actual code, not general NestJS knowledge.

Use this map to find the right files quickly:

Topic Files to read
Request lifecycle src/common/request/request.module.ts, src/common/request/guards/jwt-access.guard.ts, src/common/request/guards/roles.guard.ts, src/common/response/interceptors/response.interceptor.ts, src/common/response/filters/response.exception.filter.ts
Auth flow src/modules/auth/services/auth.service.ts, src/modules/auth/providers/jwt-access.strategy.ts, src/modules/auth/providers/jwt-refresh.strategy.ts
Module wiring src/app/app.module.ts, src/common/common.module.ts, src/common/database/database.module.ts
Database / Prisma src/common/database/services/database.service.ts, prisma/schema.prisma, prisma/prisma.config.ts
Response shaping src/common/response/interceptors/response.interceptor.ts, src/common/response/services/response.serializer.service.ts, src/common/response/dtos/response.success.dto.ts
Error handling src/common/response/filters/response.exception.filter.ts, src/common/message/services/message.service.ts
Caching src/common/cache/services/cache.service.ts, src/common/cache/cache.module.ts
Logging src/common/logger/services/logger.service.ts, src/main.ts
API docs src/common/doc/decorators/doc.api-endpoint.decorator.ts, src/swagger.ts
Docker setup Dockerfile, docker-compose.yml, docker-entrypoint.sh
Testing patterns test/modules/user.service.spec.ts, test/modules/auth.service.spec.ts, test/jest.json

Structure your explanation as:

  1. What it does — one sentence summary
  2. How it works — step-by-step with file:line references for each step
  3. Key design decisions — why it's built this way (patterns, trade-offs)
  4. How to extend it — what to change if someone wants to add to or modify this behaviour
Changes

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.

  1. 2d ago First seen · 26 lines · 0 tokens per session scan A dc51b6d5df18

Subscribe to this mod's changes

explain is a command published in the GitHub repository hmake98/nestjs-starter (61 stars, last pushed 3mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 476 tokens. 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 2026-08-30.