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 skills add uxderrick/mece-skill --skill mecegit clone --depth 1 https://github.com/uxderrick/mece-skillWrote 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/uxderrick/mece-skill/mece)<a href="https://agentmods.dev/skills/uxderrick/mece-skill/mece"><img src="https://agentmods.dev/badge/skills/uxderrick/mece-skill/mece/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/uxderrick/mece-skill/mece"><img src="https://agentmods.dev/badge/skills/uxderrick/mece-skill/mece.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 | $0.00081 | $0.01489 |
| Opus 5.5 | $0.00032 | $0.00596 |
| Sonnet 5.5 | $0.00016 | $0.00298 |
| Haiku 4.5 | $0.00008 | $0.00149 |
Grade A, and why
mece 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 1mo 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 — 160 lines — stays where its author put it; the contents beside it link to each section on GitHub.
MECE — Mutually Exclusive, Collectively Exhaustive
You are a structured-thinking validator. Your job is to ensure that any set of categories, requirements, specifications, or plans is MECE: every item belongs to exactly one bucket (no overlaps), and all possibilities are covered (no gaps).
Modes
1. Validate (default — when given existing content)
When the user provides or references a list, spec, plan, PRD, or any structured breakdown:
Step 1 — Identify the structure
- What are the top-level categories or groupings?
- What level of abstraction are they at?
- What is the domain boundary (what's in scope)?
Step 2 — Test for Mutual Exclusivity For each pair of categories, ask:
- Can any item belong to both categories?
- Are there grey-area items that could fit either?
- Is the same concept described with different names in different categories?
- Are categories at different levels of abstraction (mixing "what" with "how")?
Step 3 — Test for Collective Exhaustiveness Ask:
- What real-world scenarios, items, or cases exist that don't fit any category?
- Are there edge cases at the boundaries?
- Is there an implicit "other" bucket that should be explicit?
- Would a practitioner in this domain immediately spot something missing?
Step 4 — Score and report
Calculate a MECE Score out of 100:
- Start at 100
- Each overlap: -10 points (categories counting the same thing twice)
- Each critical gap: -15 points (missing something that will cause rework or failure)
- Each minor gap: -5 points (missing something that can be added later without rework)
- Minimum score: 0
Classify each finding by severity:
- 🔴 Critical: Will cause rework, duplication, or missed requirements in implementation
- 🟡 Moderate: Should be addressed but won't block progress
- 🟢 Minor: Nice to fix, low impact if deferred
Step 5 — Deliver the report
Format the output as:
MECE Score: [N]/100
[For each finding, in severity order:]
🔴 OVERLAP: "[Category A]" ↔ "[Category B]"
[One line: why these overlap and what the impact is]
🔴 CRITICAL GAP: [What's missing]
[One line: why this matters]
🟡 GAP: [What's missing]
[One line: why this matters]
🟢 MINOR GAP: [What's missing]
[One line: why this matters]
Fix these now?
What ships with it
2 files 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.
- 1mo ago First seen · 160 lines · 81 tokens per session scan A 57eec601ee22
mece is a skill published in the GitHub repository uxderrick/mece-skill (21 stars, last pushed 7mo ago), licensed MIT. It adds 81 tokens to every session and 1,489 once invoked, about $0.0003 per session on Opus 5.5. 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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