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 agentmods add rules/prisma/prisma-next/use-if-definedgit clone --depth 1 https://github.com/prisma/prisma-nextWrote 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/rules/prisma/prisma-next/use-if-defined)<a href="https://agentmods.dev/rules/prisma/prisma-next/use-if-defined"><img src="https://agentmods.dev/badge/rules/prisma/prisma-next/use-if-defined.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 | $0.00000 | $0.00311 |
| Opus 5 | $0.00000 | $0.00156 |
| Sonnet 5 | $0.00000 | $0.00062 |
| Haiku 4.5 | $0.00000 | $0.00031 |
Grade A, and why
use-if-defined 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 yesterday.
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.
This is a copy
94% identical to use-if-defined — 4 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
What it actually says
Use ifDefined() for Conditional Object Spreads
CRITICAL: Use ifDefined from @prisma-next/utils/defined instead of inline conditional spread patterns.
Why?
- Cleaner, more readable syntax
- Explicit about which properties are optional
- Satisfies
exactOptionalPropertyTypes - Preserves falsy values (0, '', false, null) — only excludes
undefined
Examples
❌ WRONG: Inline conditional spread
const obj = {
required: 'value',
...(options.default ? { default: options.default } : {}),
...(options.name !== undefined ? { name: options.name } : {}),
};
✅ CORRECT: Using ifDefined
import { ifDefined } from '@prisma-next/utils/defined';
const obj = {
required: 'value',
...ifDefined('default', options.default),
...ifDefined('name', options.name),
};
Behavior
ifDefined('key', value)returns{ key: value }whenvalue !== undefinedifDefined('key', undefined)returns{}- Falsy values like
0,'',false, andnullare preserved
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.
- yesterday First seen · 45 lines · 0 tokens per session scan A 74355c228ec5
use-if-defined is a cursor rule published in the GitHub repository prisma/prisma-next (419 stars, last pushed 10d ago), licensed Apache-2.0. It costs nothing until one of its globs matches a file; then it loads 311 tokens. A static security scan graded it A with 0 findings. It is 94% identical to use-if-defined, differing in 4 lines, and is treated as a copy.
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type-extraction-from-contract
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required-key-undefined-fields
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use-if-defined
Use ifDefined() for conditional object spreads.
test-mocking-patterns
Test-only type assertions and mocking patterns (avoid brittle mocks).