A client brief for AI is a short, structured document that tells AI tools who a client is: what they sell, at what price, to whom, in what voice, and what has been decided. The template below, client.md, is a free Markdown file with fixed sections and a source and date on every fact. Fill one per client and drop it into Claude, ChatGPT, Gemini or any AI tool.
Unlike a creative brief, which describes one project, a client brief for AI describes the client. It is the client layer and decisions layer of the Agency Context Stack, written down once and shared by everyone on the account.
The template
Copy everything below into a file named client.md, one per client. Replace the bracketed text and delete any line that doesn't apply. Each fact ends with where it came from and when someone last checked it.
# [Client name] — client brief for AI
Owner: [name] · Last verified: [YYYY-MM-DD] · Version: [1]
## How to use this brief
- Treat every fact below as true as of its verified date.
- If something you need is not in this brief, say so and ask. Do not guess.
- Never mix this client's facts with another client's.
- The Rules section overrides general best practices.
## Company
- What they do: [one sentence] (source: [url] · verified [date])
- Based in / serves: [location, markets] (source: [url] · verified [date])
- Founded: [year] (source: [url] · verified [date])
## Offerings
- [Product or service]: [what it is, who it is for] (source: [url] · verified [date])
- [Product or service]: [...] (source: [url] · verified [date])
## Pricing and offers
- [Plan or package]: [price, billing period] (source: [url] · verified [date])
- Current promotion: [offer, or "none"] · valid until [date] (source: [url] · verified [date])
## Audiences
- Primary: [who, size, role, situation] (source: [url or team] · verified [date])
- Secondary: [...] (source: [...] · verified [date])
## Positioning
- In one line: [how the client describes itself] (source: [url] · verified [date])
- Main differentiators: [2–3 points] (source: [url] · verified [date])
- Competitors, for context only: [names] (source: [team] · verified [date])
## Claims and proof
- Approved claims: [statistic, award, customer name] (source: [url or client] · verified [date])
- Claims to avoid: [anything unproven or retired] (source: [client] · verified [date])
## Voice
- Tone: [3 adjectives, e.g. plain, warm, direct]
- Words we use: [...]
- Words we never use: [...]
- An on-voice sentence: "[a real sentence from the client's site]" (source: [url])
## People
- Approver: [name, role]
- Spokesperson for quotes: [name, role]
## Rules
- [Do or don't, legal wording, required disclaimers] (source: [client or team] · added [date])
## Goals and decisions
| Date | Decision | Decided by |
| --- | --- | --- |
| [YYYY-MM-DD] | [what was decided] | [name] |
## Open questions
- [Something the AI or the team needed that this brief does not answer yet]
---
Template: client.md by SagaJoe (sagajoe.com/learn/client-brief-template) · CC BY 4.0
Free to use, adapt and share under CC BY 4.0. Keep the credit line at the bottom of the file.
How to fill each section
Start with what the client's website says, then add what only your team and the client know. The sections that change fastest are the ones to check most often.
What goes in each section of client.md, where to find it, and how often to check it
Section
What goes in
Where to find it
Check it
Company
What they do, where, since when
Home and about pages
Quarterly
Offerings
Each product or service and who it is for
Services or product pages
Monthly
Pricing and offers
Plans, prices, billing, current promotions
Pricing page, recent ads, client emails
Weekly
Audiences
Who buys, in plain words
About page, sales decks, the client
Quarterly
Positioning
The one-line pitch and 2–3 differentiators
Home page headline, the client's own deck
Monthly
Claims and proof
Statistics, awards, customers you may cite, and retired claims
Case studies, the client
Monthly
Voice
Tone, words to use and avoid, one real example
Blog, brand guide, past approved work
Quarterly
People
Who approves, who can be quoted
Kickoff call, the client
When it changes
Rules
Legal wording, do's and don'ts
The client, your team's experience
When it changes
Goals and decisions
What was agreed, rejected or asked for, with a date
Meetings, emails, chat threads
Every week
Open questions
Gaps the AI or a teammate ran into
Your team
Every week
Three habits make the difference:
Write facts, not adjectives. "Starter plan is $49/month, billed monthly" beats "affordable pricing".
Keep it short. Aim for one to two pages. A long brief buries the facts the AI needs, and nobody maintains it.
Ask the client to confirm it. Send the filled brief at kickoff and once a quarter. It is the fastest way to catch what changed.
A filled example
Here is the template filled in for Acme Analytics, a fictional B2B software client. Notice how short it is: everything an AI needs, nothing it doesn't.
# Acme Analytics — client brief for AI
Owner: Julie Tremblay · Last verified: 2026-11-03 · Version: 7
## How to use this brief
- Treat every fact below as true as of its verified date.
- If something you need is not in this brief, say so and ask. Do not guess.
- Never mix this client's facts with another client's.
- The Rules section overrides general best practices.
## Company
- What they do: product analytics for B2B software teams (source: acme.com/about · verified 2026-11-03)
- Founded: 2019 (source: acme.com/about · verified 2026-11-03)
## Offerings
- Acme Insights: dashboards showing how customers use a software product (source: acme.com/product · verified 2026-11-03)
## Pricing and offers
- Starter: $49/month, billed monthly (source: acme.com/pricing · verified 2026-11-03)
- Free trial: 14 days, no credit card required (source: acme.com/pricing · verified 2026-11-03)
- Current promotion: none
## Audiences
- Primary: marketing teams at B2B software companies with 20–200 employees (source: acme.com/about · verified 2026-11-03)
## Positioning
- In one line: product analytics a marketer can set up without a developer (source: acme.com · verified 2026-11-03)
## Claims and proof
- Claims to avoid: "#1 analytics tool" was retired in September (source: client email · verified 2026-09-18)
## Voice
- Tone: plain, direct, friendly
- Words we use: "you", "your team"
- Words we never use: "users", "leverage", "revolutionary"
## People
- Approver: Marc Gagnon, Head of Marketing
## Rules
- Never mention competitors by name. (source: kickoff call · added 2026-03-12)
## Goals and decisions
| Date | Decision | Decided by |
| --- | --- | --- |
| 2026-10-28 | Q4 content focuses on the free trial, not the Starter plan | Marc Gagnon |
| 2026-09-18 | Drop the "#1 analytics tool" claim | Marc Gagnon |
## Open questions
- What is the refund policy for annual plans?
---
Template: client.md by SagaJoe (sagajoe.com/learn/client-brief-template) · CC BY 4.0
How to use client.md in your AI tools
The same file works everywhere. What matters is that every tool on the account reads the same, current version.
Where client.md goes in each AI tool
Tool
Where client.md goes
Tip
Claude Projects
Upload it to the client's project knowledge
One project per client; add a line to the project instructions: "Use client.md as the source of truth for this client."
ChatGPT custom GPT or Project
Add it as a knowledge file
Re-upload after each update; old copies keep answering with old facts.
Gemini Gems
Add it to the Gem's knowledge
Same rule: replace the file, don't add a second version.
One-off chats, any tool
Paste it at the top of the conversation
Fastest option for a quick task or a new tool.
Freelancers and contractors
Send the file with the brief for the job
Ask them to delete old copies when a new version arrives.
The weak point in every setup is the copy. Each tool holds its own copy of the file, and every copy goes stale on its own. Keep one master file, give it a version number, and replace it everywhere when it changes.
Six rules for a client.md that stays trustworthy
One file per client. Never a shared file for several clients; facts leak between them.
A source and a date on every fact. If you can't say where a fact came from, it doesn't go in.
One owner. A named person updates the master file. Everyone else reports errors to them.
Decisions are facts too. Log what the client approved or rejected, with a date, in the same file.
Fix the file, not the chat. When the AI gets something wrong, correct client.md so every future draft improves.
Check what moves, weekly. Pricing, offers and decisions change fastest. A brief nobody has verified in a month is drifting (what is context drift?).
FAQ
What is a client brief for AI?
A short, structured document that describes a client for AI tools: what they sell, prices, audience, voice, rules and decisions. It lets any AI assistant work from the same verified facts.
How is it different from a creative brief?
A creative brief describes one project: its goal, deliverable and deadline. A client brief for AI describes the client itself and is reused for every project.
Why Markdown?
Every AI tool reads plain text well, Markdown keeps the sections clear, and the file is easy to edit, version and paste anywhere.
How long should a client brief for AI be?
One to two pages. Long briefs bury the important facts and rarely get maintained.
How often should I update it?
Check pricing, offers and decisions weekly. Review the whole file quarterly, ideally with the client.
Can I use the same template for every client?
Yes. The sections stay the same; only the facts change. That consistency also makes briefs easier to compare and hand over.
Is client.md an official standard?
No. It is a free template published by SagaJoe. Use it, adapt it and share it.
Keep it current without the weekly chore
The template is free and works on its own. SagaJoe does the maintenance part for you: it builds the client brief from the client's website with a source on every fact, re-checks it every week, and sends one note listing only what changed, for you to approve. See how it works.
