every-error-regression-test

A rule requiring a regression test for every defect or failure found during development.

In plain words
What is it for?
It is used when investigating bugs or failed behavior to add a test that reproduces the issue and confirms the fix.
Why use it?
It helps prevent a fixed problem from returning unnoticed in a later change.

Cursor rule

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 rules/tacc/hpcperfstats/every-error-regression-test
Clone the repo
git clone --depth 1 https://github.com/TACC/HPCPerfStats
Per session 816 This file is loaded in full into every session.
When invoked 816 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
Origin unknown 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 $0.00816 $0.00816
Opus 5 $0.00408 $0.00408
Sonnet 5 $0.00163 $0.00163
Haiku 4.5 $0.00082 $0.00082

Measured 2d ago against content hash 8d603c52a305, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

every-error-regression-test 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.

hpcperfstats/cursor-rules/every-error-regression-test.mdc · 44 lines

The source is not reproduced here

Licensed LGPL-2.1

The repository is licensed LGPL-2.1, which this catalogue does not treat as permission to reproduce the file. Read it at the source.

Read it on GitHub

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 · 44 lines · 816 tokens per session scan A 8d603c52a305

Subscribe to this mod's changes

every-error-regression-test is a cursor rule published in the GitHub repository TACC/HPCPerfStats (58 stars, last pushed 2d ago), licensed LGPL-2.1. It adds 816 tokens to every session, about $0.0041 per session on Opus 5. 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.