Difference
SkillAI & modelsLets your agent quickly compare two or more options or explain how sentences differ, answering from its own knowledge.
Available today. Use it from your connected AI after setup.
No other account needed.
Add ahel to your AI once: Claude, ChatGPT, Cursor, Claude Code or Codex. Then ask it to use this.
Then ask your AI: use the Difference skill
About this skill
Compare A vs B, weigh pros and cons of A, B, C, ..., or explain the nuance between sentences, a quick answer from what the model already knows
What this skill tells your AI
The instructions your AI receives, as published by vinta/hal-9000 in skills/difference/SKILL.md and read by ahel’s review.
The user wants a fast answer, not research. Invoking this skill is their explicit opt-out of any standing rule to check docs or search before answering: answer from what you already know.
Compare what the arguments name. With no arguments, compare the items just discussed; ask only when nothing comparable is there.
Lookups
Run one web search only for an item you cannot identify at all, such as a tool released after your training or an unknown term, then answer. Being unsure of an item's latest version does not count. Use no subagents.
Answer
Keep it as short as the question allows, and let the items decide the shape. Spend the words on where they actually differ, not on what they share.
- Alternatives someone picks between (tools, approaches, patterns): give each one's pros and cons.
- Sentences: how each lands differently — tone, implication, what a reader infers.
- An answer that hinges on a version, price, or "latest" fact: add one line saying it is as of your training data.
The last line of the answer is still comparison: no verdict, no offer to dig deeper.
Signals
- GitHub stars
- 138
- Forks
- 25
- Last commit
- Sep 2026
Advanced
- Catalog kind
- skill
- Key
difference- Source
- github.com/vinta/hal-9000