Borrowing it
Nothing to install: this file belongs to zotoio/CRUX-Compress. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/zotoio/CRUX-Compress/main/.cursor/skills/crux-utils/SKILL.mdgit 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/skills/zotoio/crux-compress/crux-utils)<a href="https://agentmods.dev/skills/zotoio/crux-compress/crux-utils"><img src="https://agentmods.dev/badge/skills/zotoio/crux-compress/crux-utils/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/skills/zotoio/crux-compress/crux-utils"><img src="https://agentmods.dev/badge/skills/zotoio/crux-compress/crux-utils.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00040 | $0.00855 |
| Opus 5 | $0.00020 | $0.00428 |
| Sonnet 5 | $0.00008 | $0.00171 |
| Haiku 4.5 | $0.00004 | $0.00085 |
Grade A, and why
crux-utils 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 12d 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.
How it starts
The opening of the file, as written. The whole thing — 112 lines — stays where its author put it; the contents beside it link to each section on GitHub.
CRUX Utils
Multi-purpose utility for CRUX compression workflows. Provides deterministic tools for token estimation and checksum calculation.
Quick Start
# Token count estimation
python3 .cursor/skills/crux/crux-utils/scripts/crux-utils.py --token-count <file>
# Compare source vs CRUX (ratio mode, default target 25%)
python3 .cursor/skills/crux/crux-utils/scripts/crux-utils.py --token-count --ratio <source> <crux>
# Compare with custom target (e.g. 40%)
python3 .cursor/skills/crux/crux-utils/scripts/crux-utils.py --token-count --ratio <source> <crux> --target 40
# Get checksum for sourceChecksum frontmatter
python3 .cursor/skills/crux/crux-utils/scripts/crux-utils.py --cksum <file>
Modes
--token-count <file>
Estimate token count for a single file.
Output:
=== Token Estimate: example.md ===
Prose tokens: 397
Code tokens: 0
Special tokens: 0
---
TOTAL TOKENS: 397
--token-count --ratio <source> <crux> [--target <n>]
Compare source file vs CRUX file and calculate compression ratio.
The --target option sets the compression target percentage (1-100). Defaults to 25 if omitted, matching the CRUX spec's recommended target for text/code content.
Output:
=== Compression Ratio Analysis ===
=== Token Estimate: source.md ===
...
=== Token Estimate: source.crux.md ===
...
=== Compression Summary ===
Source tokens: 397
CRUX tokens: 140
Ratio: 35.2% of original
Reduction: 64.8%
Target (≤25%): NO
--cksum <file>
Get checksum of a file, formatted for CRUX frontmatter sourceChecksum field.
Output:
=== Checksum: example.md ===
Checksum: 1234567890
---
FRONTMATTER: "1234567890"
Token Estimation Method
| Content Type | Chars/Token | Notes |
|---|---|---|
| Prose (markdown) | 4.0 | English text, headers, lists |
| Code blocks | 3.5 | More symbols, shorter identifiers |
| Special chars | 1.0 | CRUX Unicode symbols |
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 12d ago First seen · 112 lines · 40 tokens per session scan A e14528591106
crux-utils is a skill published in the GitHub repository zotoio/CRUX-Compress (8 stars, last pushed 5d ago), licensed MIT. It adds 40 tokens to every session and 855 once invoked, about $0.0002 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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