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/jstxn/rein/rein-scopegit 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-scope)<a href="https://agentmods.dev/rules/jstxn/rein/rein-scope"><img src="https://agentmods.dev/badge/rules/jstxn/rein/rein-scope.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 | $0.00027 | $0.00338 |
| Opus 5 | $0.00014 | $0.00169 |
| Sonnet 5 | $0.00005 | $0.00068 |
| Haiku 4.5 | $0.00003 | $0.00034 |
Grade A, and why
rein-scope 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 5d 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-scope
Use this when the work as stated is too large for a single pass, contains contradictions, or needs explicit boundaries before implementation begins.
When To Use
- The request implies more work than can be safely completed in one session
- Requirements contradict each other or contradict existing behavior
- The user asks for everything but constraints demand tradeoffs
- Scope creep is likely without an explicit boundary
When Not To Use
- The task is already well-scoped with clear acceptance criteria
- Deep-interview has already produced a spec with explicit non-goals
- The user explicitly asks to skip scoping
Steps
- Restate the full request as understood.
- Identify every distinct deliverable implied by the request.
- Classify each deliverable:
- must: required for the work to be considered complete
- should: valuable but deferrable without breaking the core intent
- will not: explicitly out of scope for this pass
- For each contradiction or tension, state the conflict and propose a resolution with tradeoffs.
- Identify what information is missing to commit to the scope.
- Present the scope contract for user confirmation before proceeding.
Output
Emit a scope contract with:
- restated request
- must / should / will-not classification
- conflicts identified and proposed resolutions
- missing information
- explicit confirmation request
Do not begin implementation until the user confirms the scope contract.
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.
- 5d ago First seen · 46 lines · 27 tokens per session scan A e602ca392a26
rein-scope is a cursor rule published in the GitHub repository jstxn/rein (12 stars, last pushed 3mo ago), licensed MIT. It adds 27 tokens to every session and 338 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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