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/fix-the-class-not-the-instancegit clone --depth 1 https://github.com/prisma/prisma-nextWhat 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 | $0.00403 | $0.00403 |
| Opus 5 | $0.00201 | $0.00201 |
| Sonnet 5 | $0.00081 | $0.00081 |
| Haiku 4.5 | $0.00040 | $0.00040 |
Grade A, and why
fix-the-class-not-the-instance 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.
This is a copy
100% identical to fix-the-class-not-the-instance — 0 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
Fix the class, not the instance
When a reviewer flags a defect, the flagged line is an example, not the scope. Treating it as a point-fix makes the reviewer re-find the same defect in the next round at review cost — the most expensive possible linter.
Required response to any review comment
- Name the class. State the general rule the instance violates ("SQL vocabulary on a framework type", "strategy encoded as a string enum", "logic in a shared-types module").
- Sweep the entire PR diff for the class before replying — grep plus reading, not just the flagged file. Include surface the PR added to pre-existing types, not only new types.
- Fix every instance in one round. If an instance is genuinely out of scope (pre-existing, not touched by this PR), say so explicitly with evidence and a tracking ticket — and remember grandfathering never covers surface this PR authored.
- The reply states the sweep: what class, what was searched, what was found and fixed, what was excluded and why.
Don't
- Don't fix the flagged line and re-ship — the next round finding the same class elsewhere in the diff is a process failure, not a new finding.
- Don't treat design as settled because a doc or an earlier round blessed it. Design is never settled; a reviewer comment that invalidates a design invalidates every consequence of it, and the sweep must chase those consequences.
- Don't have a reviewer subagent inherit the author's framing. Review-pass briefs state the class-sweep duty and the relevant layer/vocabulary audits explicitly (for framework-touching diffs: every added line under
packages/1-frameworkjustified against the family-blindness test).
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.
- 2d ago First seen · 22 lines · 403 tokens per session scan A ca20c2bf446a
fix-the-class-not-the-instance is a cursor rule published in the GitHub repository prisma/prisma-next (420 stars, last pushed 7d ago), licensed Apache-2.0. It adds 403 tokens to every session, about $0.0020 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to fix-the-class-not-the-instance, differing in 0 lines, and is treated as a copy.
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