ENG-11 · SEC. 01 Engineering & Coding

Integration Decision Checklist

Before adding any new dependency or service, check for an existing alternative and the real cost first.

FORMAT: goal
DIFFICULTY: intermediate
TIME: 10 min
TOOLS: claude-code · cursor · codex-cli · gemini-cli
MODELS: any
COPIES: 0 so far

When to use this

You're about to install a new library or wire up a new third-party service, and want to make sure it's actually needed before it becomes one more thing to maintain, key-rotate, and keep updated. Use it before adding the dependency, not after it's already in package.json.

The pattern

Pastes as plain text

I'm considering a new dependency. It's named at the end of this message, along with the problem it solves. Run it through a decision checklist before I install anything.

1. Check what's already in the project (package.json / existing services) — is there something already installed that covers 80%+ of this need without adding a new dependency?
2. If it's a well-known service category (auth, payments, email, file storage, error monitoring, etc.), name the 1-2 most common choices and note if any has first-class agent/CLI tooling that would make it faster to integrate and maintain than a lesser-known alternative.
3. State the real ongoing cost of adding this: a new API key to manage, a new thing that can break/rate-limit/go down, a new item in the dependency update cycle. Be concrete, not generic.
4. Give a clear go/no-go recommendation, and if go, the exact install command.
5. If no-go, name the lighter alternative (an existing dependency, a small hand-rolled function, or "you don't need this yet").

Library or service:
Problem it solves:

Real example output

Library or service: lodash
Problem it solves: need a deep object comparison for a diffing feature.

1. Checked package.json — no existing deep-equal utility. Node's built-in util.isDeepStrictEqual exists but isn't imported anywhere yet.

2. Not really a "well-known service category" case — this is a narrow utility need, not auth/payments/etc.

3. Real cost of lodash: 70KB+ if not tree-shaken correctly (this project doesn't have tree-shaking configured in its current build), one more dependency to keep patched, and you'd likely only use 1 of its ~300 functions.

4. No-go on lodash for this. Use Node's built-in util.isDeepStrictEqual instead — zero new dependency, zero new attack surface, does exactly what's needed.

5. Alternative: `import { isDeepStrictEqual } from 'node:util'` — already available, no install step.

Why it works

Every dependency added is a standing cost, updates, security patches, a key to manage if it's a service, that outlives the five minutes it saved during implementation. Checking for an existing alternative first turns "just install it" into a decision you'd stand behind six months later.