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/zotoio/CRUX-CompressWrote 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/zotoio/crux-compress/_crux-rule)<a href="https://agentmods.dev/rules/zotoio/crux-compress/_crux-rule"><img src="https://agentmods.dev/badge/rules/zotoio/crux-compress/_crux-rule/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/zotoio/crux-compress/_crux-rule"><img src="https://agentmods.dev/badge/rules/zotoio/crux-compress/_crux-rule.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 | $0.00408 | $0.00408 |
| Opus 5 | $0.00204 | $0.00204 |
| Sonnet 5 | $0.00082 | $0.00082 |
| Haiku 4.5 | $0.00041 | $0.00041 |
Grade A, and why
_CRUX-RULE 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
Foundational CRUX Rules (MUST FOLLOW)
If not already loaded in context, load CRUX.md and AGENTS.md from the project root.
When you encounter CRUX notation, use the 'CRUX Rule Compression Specification' in CRUX.md to help you understand and adhere to the rules or intents it contains.
CRUX Decompression - CRITICAL
Always interpret, understand and adhere to the meaning compressed in CRUX notation! NEVER forget this.
Path Construction - CRITICAL
When constructing paths, URIs, or tool calls from CRUX references, preserve the literal path, filename, and extension exactly as they exist in the repository.
CRUX Compression - CRITICAL
When asked to compress a markdown rule file, delegate this to the crux-cursor-rule-manager subagent that adheres to this spec.
CRUX Compressed File Protection - CRITICAL
NEVER edit files that are CRUX compression output. These are:
- Files with
.crux.mdor.crux.mdcextensions - Files whose frontmatter contains both
generated:andsourceChecksum:orsourceUrl: - Files that carry the banner
> [!IMPORTANT] > Generated file - do not edit!
Always edit the corresponding SOURCE file instead, then re-generate the derived CRUX output.
[name].crux.md/[name].crux.mdc-> edit the real source file such as[name].mdAGENTS.mdis a source file in this repository; do not inventAGENTS.source.md
If you are about to edit a file and it contains sourceChecksum, sourceUrl, or the generated-file banner, stop and move the change to the source file instead.
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 · 34 lines · 408 tokens per session scan A e50424945f9e
_CRUX-RULE is a cursor rule published in the GitHub repository zotoio/CRUX-Compress (8 stars, last pushed 2d ago), licensed MIT. It adds 408 tokens to every session, about $0.0020 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 2026-08-31.
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