strict-api

---
name: strict-api
description: Use when the user says 'no hallucinations', 'verify APIs', 'reality check', or 'don't invent functions'; prevents calling non-existent methods, imports, or variables.
category: Engineering
version: 1.0.0
tools: []
---

# Strict API Verification

Reality-check layer applied before any code is written: use only what provably exists in the user's installed version.

## The Only Rule

Before you call a function, import, or access a method, you must answer: **Does this exist in the version the user is running?**

If the answer is "probably" or "I think so" — **stop**. You don't know. Say so.

## What This Blocks

**Made-up methods:**
- `fs.readFileLines()` does not exist in Node.js
- `path.combine()` is .NET, not Node.js
- `csv.read_csv()` is pandas, not Python's `csv` module

**Framework confusion:**
- `render_template` (Flask) vs `render()` (Django)
- `useForm()` (react-hook-form) vs nothing built into React
- `app.listen()` (Express) vs `server.listen()` (Node.js `http`)

**Deprecated APIs** break on upgrade.

## Workflow

1. Identify every API surface in the code you're about to write: imports, method calls, class instantiations
2. Verify each one against the user's stated version; ask for version if not stated
3. Flag anything uncertain with an inline comment rather than silently guess
4. Prefer verbose-but-correct over terse-but-wrong

When uncertain, annotate:
```
// verify fs.openAsBlob exists in your Node.js version (>= 20.0)
```

One comment costs nothing. A silent wrong call costs an hour of the user's time.

If uncertainty is too high, ask for the version explicitly.

## Anti-Patterns

| Anti-Pattern | What to do instead |
|---|---|
| Write a method call you vaguely remember | Stop and verify the exact signature |
| Silently use a deprecated API | Use the current API and note the deprecation |
| Assume API parity across frameworks | Explicitly name the framework and version |
| Guess import paths | Check the package's actual export structure |
| Use an API from a different language's stdlib | Verify it exists in this language |
| Write "it should work" without checking | Ask what version the user is on |