Free starter lessonClaude22 min

Build a brand-voice system in a Claude Project

By the end you will have a reusable Claude Project that loads your brand voice, rules, and audience personas into every new chat, so drafts start on-brand instead of generic.

Every caption you write starts from a blank doc, so the first ten minutes go to reminding the tool who you are and who you are talking to. A voice project moves that briefing out of every chat and into one place, so drafts open on-brand and your edits are about the idea, not the tone.

It is the foundation the rest of the weekly system stacks on.

This is the free first module of urfired.ai's Content & Marketing path. No signup, no card. The steps note what Claude access you need.

The workflow

8 steps, start to finish

Create the project

In claude.ai, open Projects in the left sidebar and click New Project. Name it for your brand or channel, like "Acme social voice," not "Project 1," and add a one-line description of what it is for.

Free accounts can hold up to five projects, so dedicate one to voice and keep it. Every chat you start inside it inherits its instructions and files automatically.

Gather your real voice inputs first

Before writing anything, pull three of your best posts, the ones that sounded most like you and actually landed. Add one longer piece you are proud of and a short note of words and phrases you never use.

This is the raw material for the whole project. Do not skip ahead to describing your voice in adjectives; show it with real work.

Write the custom instructions, constraints first

Inside the project, click Set project instructions. Lead with what Claude must not do (no "in today's fast-paced world," no em dashes, no hashtag stacks unless asked), then your role and the platforms you write for, then your tone in three or four concrete words.

Put the hardest rules first, since earlier lines carry more weight. Keep this to behavior and rules, not background.

Reverse-engineer a one-page voice brief and upload it

Open a chat in the project, paste your three posts, and ask Claude to derive a one-page voice brief: sentence length, rhythm, vocabulary, how you open and close, how you sound when you disagree. Edit it until it is actually true to you.

Save it as a text or PDF file and upload it to the knowledge base using the + on the right of the project page. Keep it to one to three pages so the signal stays dense.

Define two audience personas as a second file

Write a short file describing the two people you actually post for: what they want, what they scroll past, the words that land, the objections they carry. Upload it alongside the voice brief.

This is what turns an on-voice draft into an on-target one, so posts are aimed rather than just well-written.

Add a do-not and AI-tells kill list

Add a short, specific list of the tells you want gone: cliches, hedges, corporate filler, and any phrasing that reads as machine-written. Put it in the instructions or as its own short file.

This is the highest-leverage piece, because it directly kills the sameness that makes AI drafts sound identical.

Test on one real brief and compare

Start a fresh chat in the project and give it one real one-line brief you owe this week. Set the draft next to something you would normally write by hand.

Where it drifts off-voice or off-audience, that gap is a missing rule, not a reason to abandon the setup.

Iterate the instructions from what it got wrong

Fix the setup, not the single output. Tighten a rule, add a missed phrase to the kill list, or sharpen a persona, then rerun the same brief.

After roughly three passes the project should start most drafts close enough to edit rather than rewrite. Update it again whenever you catch it repeating a mistake.

Do this now

Take one real one-line brief you owe this week and build a Claude Project around your own voice to draft it. Create the project, paste in your three best-performing posts, and have Claude derive a one-page voice brief you correct and upload.

Add a two-persona file and a do-not list, then run your brief in a fresh project chat and set the output next to what you would have written. Tighten the instructions from what it missed and rerun until the draft needs edits, not a rewrite.

What you keep

A Claude Project named for your brand, with custom instructions holding your voice rules and a do-not list, plus a one-page voice brief and a two-persona file in its knowledge base, tested on one real brief so new chats start on-brand automatically.

What good looks like
  • A new chat in the project produces a draft that sounds like you with light edits, not a full rewrite.
  • The draft avoids every phrase on your do-not list and speaks to one of your two personas.
  • Someone else could open the project, read the instructions and files, and describe your voice without asking you.
  • You stop pasting a voice reminder into each chat because the project loads it for you.
Common traps
Describing your voice in adjectives ("punchy, authentic") instead of showing it.
Paste three real posts and have Claude derive the brief from them, then correct it line by line until it is true.
Cramming company background and product facts into the custom instructions.
Keep instructions to behavior and rules; move all background context into the uploaded knowledge files where it belongs.
Writing the instructions once and treating the first draft as done.
Run three real briefs through the project and update the instructions and kill list from what it got wrong each time.
Saved on this device
Next in this path

Module 02: Turn positioning into a month of angles and hooks with ChatGPT (ChatGPT, 18 min)

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