rein-review

rein-review is a cursor rule for Cursor from jstxn/rein. It costs 24 tokens per session (416 once invoked), scanned A, original, MIT.

A review of the current code changes before they are committed to version control.

In plain words
What is it for?
Use it after a multi-file change and before committing. It checks the full difference and examines each changed file for scope and test integrity.
Why use it?
It catches problems that automated checks may miss, such as unrelated edits, debugging leftovers, weakened tests, or work that drifted beyond the request.

Cursor rule for Cursor

Written for Cursor: installed under .cursor/.

Good fit Use it after a multi-file change and before committing. It checks the full difference and examines each changed file for scope and test integrity.

Compare 6 cursor rules from other repositories ↓
Install with agentmods
npx agentmods add rules/jstxn/rein/rein-review
View source ↗ jstxn/rein
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.

Clone the repo
git clone --depth 1 https://github.com/jstxn/rein

Made for: Cursor.

Wrote 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.

agentmods badge for rein-review

README.md
[![agentmods](https://agentmods.dev/badge/rules/jstxn/rein/rein-review/github.svg)](https://agentmods.dev/rules/jstxn/rein/rein-review)
Your own site
<a href="https://agentmods.dev/rules/jstxn/rein/rein-review"><img src="https://agentmods.dev/badge/rules/jstxn/rein/rein-review/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for rein-review

Your own site · 80×15
<a href="https://agentmods.dev/rules/jstxn/rein/rein-review"><img src="https://agentmods.dev/badge/rules/jstxn/rein/rein-review.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 24 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 416 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original 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 5.1 $0.00024 $0.00416
Opus 5 $0.00012 $0.00208
Sonnet 5 $0.00005 $0.00083
Haiku 4.5 $0.00002 $0.00042

Measured 9d ago against content hash ea02958a7ab2, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

rein-review 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 9d 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.

.cursor/rules/rein-review.mdc · 53 lines

What it actually says

rein-review

Use this after implementation and before committing to review your own diff for problems that verification commands alone will not catch.

When To Use

  • Before any commit that touches more than a trivial change
  • After a multi-file implementation pass
  • When you are about to declare work complete

When Not To Use

  • The change is a single-line typo fix with no surrounding edits
  • rein-verify has already been run and covers diff review (avoid duplication)

Steps

  1. Read the full diff (staged and unstaged).
  2. For every changed file, verify you read it before editing it.
  3. Check for unrelated changes:
    • files modified that are not part of the task
    • formatting-only changes in files you did not need to touch
    • import reordering or whitespace changes outside the task scope
  4. Check for debug leftovers:
    • console.log, print, debugger statements
    • commented-out code that should be removed
    • TODO/FIXME comments added without justification
  5. Check for test and fixture integrity:
    • tests removed or weakened without explanation
    • assertions loosened (exact match to contains, strict to loose)
    • test data changed to make failures disappear
    • new tests that only assert the happy path
  6. Check for scope drift:
    • refactors beyond what the task required
    • new abstractions or helpers for one-time use
    • feature additions not in the original scope
  7. If any issue is found, fix it before committing.
  8. If all checks pass, state what was reviewed and confirm the diff is clean.

Output

Emit a short review note with:

  • files reviewed
  • issues found (if any) and how they were resolved
  • confirmation that the diff is limited to the task scope
  • any caveats or remaining concerns
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. 9d ago First seen · 53 lines · 24 tokens per session scan A ea02958a7ab2

Subscribe to this mod's changes

rein-review is a cursor rule published in the GitHub repository jstxn/rein (12 stars, last pushed 4mo ago), licensed MIT. It adds 24 tokens to every session and 416 once invoked, about $0.0001 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.