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.
git clone --depth 1 https://github.com/jstxn/reinWrote 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/jstxn/rein/rein-retro)<a href="https://agentmods.dev/rules/jstxn/rein/rein-retro"><img src="https://agentmods.dev/badge/rules/jstxn/rein/rein-retro/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.
<a href="https://agentmods.dev/rules/jstxn/rein/rein-retro"><img src="https://agentmods.dev/badge/rules/jstxn/rein/rein-retro.svg" alt="Reviewed on agentmods" width="80" 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 5.1 | $0.00021 | $0.00156 |
| Opus 5 | $0.00010 | $0.00078 |
| Sonnet 5 | $0.00004 | $0.00031 |
| Haiku 4.5 | $0.00002 | $0.00016 |
Grade A, and why
rein-retro 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.
What it actually says
rein-retro
Use this after a miss, failed check, or suspicious shortcut.
Steps
- State what failed.
- Identify the false assumption or missed search step.
- Classify the miss:
- bluffing
- incomplete search
- insufficient verification
- reward hacking
- other
- State what evidence would have prevented the miss.
- Propose one concrete protocol improvement.
Output
Emit a short retro note with:
- failure
- root assumption
- miss classification
- missing evidence
- rule or prompt update to add back into the harness
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.
- 9d ago First seen · 32 lines · 21 tokens per session scan A cb4944e257e0
rein-retro is a cursor rule published in the GitHub repository jstxn/rein (12 stars, last pushed 4mo ago), licensed MIT. It adds 21 tokens to every session and 156 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.
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