# One-page decision brief

A free skill from Neosaipien. Version 1.1, as of 16 October 2026.

## What it does

You give your AI assistant your working material: notes, options, supplier quotes, figures and emails. The skill turns it into a one-page brief that asks your decision-maker for a clear yes, plus the evidence behind it.

You get four things:

1. **The one-page brief** (500 words or fewer): the decision needed and by when; every option, always including doing nothing, each with its cost, main benefit and main risk over the same period; a recommendation labelled as your draft view; and what you need from the decision-maker now.
2. **Likely questions**: the five to eight questions your decision-maker will probably ask, each with the answer from your material or "Not yet answered".
3. **A facts ledger**: every figure and date in the brief, marked Sourced (and where from), Unsourced, or Calculated (with the sum shown).
4. **Notes for you**: gaps to fill, assumptions made, claims in your notes that the figures do not support, anything left out (such as personal details) and why.

## Who it is for

Managers and team leads who need a yes from leadership, chiefs of staff, executive assistants, and executives who want the papers that reach them to be shorter and checkable.

## What is inside

| File | What it is |
|---|---|
| `decision-brief.zip` | The skill, ready to upload to Claude |
| `portable/decision-brief-for-gemini.zip` | The same skill, packed with `SKILL.md` in its main folder, for Gemini |
| `skill/SKILL.md` | The instructions the assistant follows. This is the file for ChatGPT, and for Gemini if it takes only one file |
| `skill/references/template.md` | The tested layout for the brief, the questions, the ledger and the notes |
| `skill/references/house-format.md` | Your own format: headings, word limit, period, extra sections. Edit it in any text editor |
| `skill/references/worked-examples.md` | Two complete worked examples: a money decision and a people-and-process decision |
| `skill/LICENSE.txt` | Licence terms |
| `portable/paste-in.txt` | A plain-text copy for a plan without skills: paste it into a project's instructions, or at the start of a chat |

The `skill` folder is a readable copy of what is inside the .zip files. The skill also works from `SKILL.md` alone: without the reference files it uses the layout written into its own steps.

## Add it to your AI tool (as of Oct 2026)

All three tools now take skills in the same open format, a SKILL.md file. The format began at Anthropic and is now an open standard. So this is one skill, not a version per tool. Use the tool your company approves for work data.

If you cannot see a menu below, the usual reasons are a rollout still in progress, your plan, your country or an admin setting.

### Claude

**Plans:** Pro, Max, Team and Enterprise, says Anthropic's skills page (its pricing table also ticks Free).

1. In **Settings > Capabilities**, turn on **Code execution and file creation**. Skills need it.
2. Go to **Customize > Skills**.
3. Upload `decision-brief.zip`. It holds the SKILL.md file and its reference files.
4. To use it, describe the task in a chat, or type **/** and pick **decision-brief**.

Anthropic does not review skills made by other people, so read a skill's files before you turn it on. This one is plain text: open `skill/SKILL.md` to read it. A skill you add in Claude also follows you into Claude Code when you sign in with the same account.

### ChatGPT

**Plans:** skills are a beta on Free and Plus, and generally available on Enterprise and Edu (since 9 Jul 2026). ChatGPT keeps skills inside plugins, in the Plugin Directory.

1. Start a new chat and type **@skill-creator**.
2. Attach `skill/SKILL.md` and the files in `skill/references/`, and write: "Make a skill from these files. Keep its name, description, instructions and reference files exactly as written."
3. Check that the skill it shows you matches the files.
4. To use it, describe the task, or type **@** and pick **decision-brief**.

### Gemini

**Plans:** 18 or over, with a personal Google Account. Google says work and school accounts get skills "soon".

1. Open the left menu, click **Customize**, then **Skills**.
2. Make a new skill by uploading a SKILL.md: choose `portable/decision-brief-for-gemini.zip`, which has the SKILL.md in its main folder with the reference files beside it. If your screen takes only a single file, choose `skill/SKILL.md`; it works on its own.
3. To use it, describe the task, or type **/** (Google says **@** is coming) and pick **decision-brief**.

Gemini wants skill names in lowercase with hyphens, which this one has, and allows up to 100 active skills.

### No skills on your plan? Use a project

- **Claude or ChatGPT:** make a project for this job and paste the whole of `portable/paste-in.txt` into the project's instructions. Every chat in that project then follows it. In ChatGPT: select **New project** in the sidebar, name it, then add instructions from the **•••** menu under **Project settings**.
- **Gemini with a work account, or any single chat:** paste `portable/paste-in.txt` as your first message. It lasts for that one chat.

There is no custom GPT or Gem version: OpenAI plans to retire custom GPTs in favour of plugins, and Google is moving Gems to skills from Nov 2026 for personal accounts and in 2027 for work and school accounts.

**For your whole organisation.** Ask whoever runs your company's Claude, ChatGPT or Gemini account to add it for your staff. Each tool has its own admin settings, and on Team and Enterprise plans an owner often has to allow things first.

## Which tool, mode and model to use

**My recommendation: Claude first, ChatGPT second, Gemini third.** (Samson, Neosaipien.) A decision brief is a careful document with sums in it, and finished documents are where Claude is strongest.

| | Claude | ChatGPT | Gemini |
|---|---|---|---|
| Where to run it | Any ordinary Claude conversation | Chat for the draft; Work if you want a finished document file | Chat; at a Google Workspace company, Gemini in Docs |
| Model | Opus 5.5 (Sonnet 5.5 for a quick first pass) | GPT-6 at High | Pro, thinking High |
| The finished file | Ask for a Claude Doc, then export it to Word, PDF or Google Docs | Work makes documents and reports | Gemini in Docs (Workspace editions) |
| Worth setting up | A project holding your house format and past briefs | A project holding your house format | Nothing extra |

- **Where to pick the model:** Claude, the model name next to the send button. ChatGPT, GPT-6 in the model menu, then the Thinking slider. Gemini, the current model at the bottom of the chat box.
- **Plans:** Opus 5.5 needs Claude Pro or above. GPT-6 at High needs ChatGPT Plus or above. Gemini's Pro needs a Google AI plan.
- **Where another tool wins:** if the brief must go into your company's own slide template, ChatGPT Work with GPT-6 Astra (limited on Plus; Pro and Business Premium seats have the full allowance) is worth a try: OpenAI calls it its best model for following existing templates (that is OpenAI's own claim). For a very high-stakes decision, Claude Fable 5.1 thinks hardest, but it is slow and uses your limit fastest.

## How to use it

1. Start a new chat with the skill on, or open the project you keep for briefs.
2. Paste or attach your material: notes, quotes, emails, figures.
3. Ask in plain words, for example: "Draft a decision brief for the Head of Operations from these notes." Say which option you favour if you have a view; if you do not, the assistant drafts one for you to replace.
4. Read the notes for you first, fill the gaps, and ask for a new version if needed.
5. Do the checks below before the brief goes anywhere.

To use your organisation's own format:

1. Open `skill/references/house-format.md` in any text editor, change the settings (headings, word limit, cost period, extra sections) and save a copy.
2. Easiest: paste your edited settings at the start of a chat with the skill on, or add them to the instructions of the project you use for briefs. The skill uses pasted settings instead of its own file.
3. To build them into the skill itself, put your copy in place of `references/house-format.md` and add the skill again, as in "Add it to your AI tool" above.

Some things cannot be switched off: doing nothing as an option, the same period for every option, the facts ledger, the draft label, and keeping personal data out.

## What you must check

The skill drafts; a person decides. Before you send a brief:

- Check every figure against the original quotes and documents, and redo the sums and dates.
- Make sure the recommendation is really your view, and that the risks are fair to each option, including the ones you do not favour.
- Check that no salary, health or other personal data is included beyond what the decision needs.
- Fill or remove every gap listed in the notes for you.

## What it does not do

- It does not look anything up. It works only from what you give it, so it cannot know about facts you leave out or tell you whether a quote is still current.
- It does not invent figures, estimate missing ones, or turn staff time into money unless you give it a rate.
- It does not send, post or share anything, and it does not contact anyone. It creates a file only if you ask.
- It does not make the decision, and it does not score or rank people.
- It can misread numbers in scans, photos and complicated tables. That is one reason the checks above matter.
- It promises no result: no approval, saving or outcome.

## Compatibility, as of October 2026

| Tool | Who can add skills (vendor's own pages) | Which file |
|---|---|---|
| Claude | Pro, Max, Team and Enterprise (the pricing table also ticks Free), with code execution on | `decision-brief.zip` |
| ChatGPT | A beta on Free and Plus; generally available on Enterprise and Edu | `skill/SKILL.md` and its reference files, through @skill-creator |
| Gemini | 18 or over, personal Google Accounts; work and school accounts "soon" | `portable/decision-brief-for-gemini.zip`, or `skill/SKILL.md` on its own |
| A plan without skills | Everyone, through a project's instructions or one chat | `portable/paste-in.txt` |

"Who can add skills" is what each vendor's own page says, as of October 2026. These tools change often.

Built to the open Agent Skills standard, using only its standard fields, with no scripts and no internet access. The skill's description is 194 characters.

## Your data

The skill sends nothing anywhere and needs no internet access. It works only with what you give it inside your assistant, and that assistant's own terms and data policies apply. Follow your organisation's rules on what you may paste into an AI assistant.

## Licence and support

Free, under the Neosaipien free licence, Version 2. Use it as much as you like, at work or at home, in any organisation. Change it to fit your team, and hand the changed version to people inside your own organisation, team, class or group, with the credit, the date and a line saying it was changed. Share unchanged copies with anyone, free of charge. Do not sell it, and do not publish a changed version outside your own group. No warranty of results. Full terms: `skill/LICENSE.txt`. Questions: samson@neosaipien.com

Neosaipien is not affiliated with Anthropic, OpenAI or Google. Product names belong to their owners.

## Sources for the setup steps (all read 16 October 2026)

- Anthropic, Skills overview: https://claude.com/docs/skills/overview.md
- Anthropic, Claude plans and pricing: https://claude.com/pricing
- Anthropic, What are projects: https://support.claude.com/en/articles/9517075-what-are-projects
- Anthropic, Connectors, skills, and plugins: https://claude.com/docs/extend/overview
- Anthropic, Change the model, effort, and thinking settings: https://support.claude.com/en/articles/8664678-change-the-model-effort-and-thinking-settings
- OpenAI, Skills and plugins: https://learn.chatgpt.com/docs/skills-and-plugins.md
- OpenAI, Build skills: https://developers.openai.com/plugins/build/skills.md
- OpenAI, ChatGPT release notes: https://help.openai.com/en/articles/6825453-chatgpt-release-notes
- OpenAI, ChatGPT plans and pricing: https://chatgpt.com/pricing/
- OpenAI, Projects in ChatGPT: https://help.openai.com/en/articles/10169521-projects-in-chatgpt
- OpenAI, GPT-6 and other models in ChatGPT: https://help.openai.com/en/articles/20001354-gpt-6-and-other-models-in-chatgpt
- Google, Create and manage skills for Gemini Apps: https://support.google.com/gemini/answer/17094296
- Google, About the transition from Gems to skills: https://support.google.com/gemini/answer/18560919
- Google, About Gemini models: https://support.google.com/gemini/answer/18648722
- Agent Skills overview: https://agentskills.io/
- OpenAI, GPT-6 Astra (3 Sep 2026): https://openai.com/index/gpt-6-astra/
- Anthropic, What are artifacts and how do I use them: https://support.claude.com/en/articles/17153992-what-are-artifacts-and-how-do-i-use-them