Make Claude sound like you.
The Customize feature lets you set Claude's behavior at the account level — voice, defaults, refusal style, length, format. Most professionals never touch it past the basics. This module walks you through every setting that actually changes the output and shows you how to build three professional personas you'll use across all your work.
Here's the move that separates working professionals using Claude well from those plateauing: they've stopped asking Claude to sound like them in every prompt. They've configured Claude to sound like them — once, persistently, across every conversation. That configuration lives in the Customize panel. This module teaches you how to use it.
What you'll walk out with
A complete tour of the Customize panel — every setting, what it does, when to use it. A personal voice audit (what does YOUR writing actually sound like?). Three configured personas — your default work voice, your customer-facing voice, your strategic voice. A trigger system for switching between them mid-conversation. And a maintenance discipline that keeps the personas sharp as your work evolves.
What this module covers
- The Customize panel — every setting, what it actually does
- The personal voice audit — diagnosing what makes your writing sound like you
- Persona 1 — Your default work voice — the one you use for 80% of work
- Persona 2 — Your customer-facing voice — more warmth, more care
- Persona 3 — Your strategic/board voice — tighter, less wandering, decision-oriented
- Style switching — moving between personas without losing context
- The "never do" list — the rules every persona inherits
Every setting that actually matters.
The Customize panel has more settings than most professionals realize. Most of them are noise — defaults that you'll never touch and that don't meaningfully change the output. A small handful actually move the needle. This page focuses on those.
Where to find it
In the Claude web interface, click your profile icon (top right) → Settings → Customize. On the desktop app, same location. The settings save automatically as you change them and apply to every conversation across every Project.
The settings that move the needle
About you
One paragraph about who you are — role, industry, audience, what you do. This is the most-leveraged single field in Customize. Claude uses it as ambient context in every conversation. Without it, Claude defaults to a generic "helpful assistant" frame.
What to write: 2–4 sentences. Job + company size + industry + audience for your work + one distinctive thing about your context.
Custom Instructions / Response preferences
The standing rules Claude follows across all conversations. Voice rules, format defaults, never-do lists. This is where your universal rules live — anything that should apply to every kind of work you do.
What to write: A short paragraph or bullet list. Active vs passive voice. Paragraph length norms. Format defaults. Banned phrases. Anything that should be true regardless of what you're working on.
Trigger phrases (a hack — not a built-in feature)
This isn't a separate setting — it's a discipline you build into your Custom Instructions. You define short trigger phrases that tell Claude to switch personas. We'll build this on Page 7 once you have all three personas defined.
The settings that don't matter much
Things you don't need to overthink: avatar choice, color preferences, font size adjustments, notification settings. These shape your experience of using Claude — they don't shape Claude's output.
The 80/20
The "About you" field and the "Custom Instructions" field together produce 80% of the personalization impact. Everything else is polish. Spend your time on these two.
What does your writing actually sound like?
Before you can tell Claude how to sound like you, you have to know what "sounding like you" actually means. Most professionals can't articulate this. The voice audit fixes that in 15 minutes.
Step 1 — Pull 5 pieces of your real writing
Find five things you've written for work in the last 6 months. A mix: an email to a customer, an internal memo, a Slack message of any length, a draft of a longer document, something casual. Not your best work — a representative sample.
Step 2 — Read them looking for patterns
For each piece, note:
- Sentence length — do you tend toward short, declarative sentences? Long, structured ones? A mix?
- Active vs passive voice — count instances of each in a paragraph. Most professionals lean one way without realizing it.
- Paragraph length — one-sentence paragraphs? Three to four? More?
- Contractions — do you write "don't" or "do not"?
- Opening moves — how do you typically start emails? Memos?
- Closing moves — how do you sign off? End paragraphs?
- Words you use a lot — note any 3–5 distinctive words or phrases that show up across multiple pieces
- Words/phrases you'd never use — be honest. What corporate jargon makes you cringe?
Step 3 — Write your voice profile
Synthesize what you found into a short profile. Aim for ~150 words. This becomes the heart of your Custom Instructions.
Example voice profile (Tina the management consultant from the main course)
VOICE. Tight, direct, plain English. Active voice. Short paragraphs (2–4 sentences). Conversational but professional — the way I'd talk to a smart operator over coffee, not the way an enablement deck reads. CONTRACTIONS: yes ("don't," "isn't," "we're"). OPENING MOVES: Get to the point. No "I hope this finds you well." No throat-clearing. If it's bad news or pushback, name it in the first sentence. CLOSING MOVES: Clear next step. Direct reply path. DISTINCTIVE WORDS: I use "the move" a lot. I say "the thing is" before contrarian takes. I describe options as "cheap" vs "expensive" relative to a decision, not in dollars. NEVER: "leverage," "synergize," "at the end of the day," "circle back," "let's unpack," em-dashes everywhere, sentences that start with "It's not just X — it's Y," exclamation points outside genuinely celebratory moments.
Your turn — 15 minutes
Write your voice profile. Use the example above as a template. Be honest — describe how you actually write, not how you think you should write.
This profile is the raw material for your three personas. We'll layer it into Custom Instructions and Project Instructions across the next four pages.
Your default work voice.
The voice you use for 80% of your work. Internal notes, team Slack, peer-level emails, drafts, brainstorms. Not your highest-stakes voice — your everyday voice. This is what goes in your top-level Customize settings.
The "About you" field
2–4 sentences. Identity + audience + distinctive context.
Template
I'm [ROLE] at [COMPANY TYPE/SIZE]. My day is split between [TYPICAL ACTIVITIES — 2–3 examples]. I write for [AUDIENCE — sharp internal teams, busy clients, etc.]. [ONE DISTINCTIVE THING — your industry's quirk, your company's stage, your role's tension].
Example — Marcus from Unit 4 (sales operations)
I'm head of sales operations at a 90-person B2B SaaS company. My day is split between sales leaders, finance, and revenue analytics. I write for sharp internal audiences who want the numbers and the call. We're at the stage where most of my reports go to a leadership team that already knows the basics — they don't want context, they want recommendations.
The Custom Instructions field
This is where your voice profile from page 3 lives. Paste it in, with one addition: a clear note about which voice this is. Claude can switch personas, but only if it knows the default.
Example — Marcus's full Custom Instructions
DEFAULT VOICE: Direct, conversational, plain English. Active voice. Short paragraphs. No filler phrases. I write the way I'd talk in a 1:1 — not the way an enablement deck reads. FORMAT: Default to bullets for analysis, prose for narrative or sensitive communication. Always lead with the recommendation, then the supporting numbers, then the caveats. NEVER: Use "leverage" or "synergize." Start an email with "I hope this finds you well." Hedge a recommendation behind three qualifiers — pick one. PERSONA SWITCHES: If I write "customer voice on" — switch to warmer, more careful tone for external communication. If I write "board voice on" — switch to tighter, decision-oriented, no narrative, no examples, headlines first.
The first test
Save Customize. Open a new conversation. Type a simple work request — something you'd do in a typical day. Read the output. Does it sound like you? Does it pick up your voice rules? Does it skip the corporate clichés you banned?
If yes, persona 1 is working. If not, refine the Custom Instructions — usually the fix is being more specific. "Direct" is vague; "no sentences over 25 words" is a rule Claude can act on.
Your customer-facing voice.
Same person. Different posture. Customer-facing work needs more warmth, more care, more reading-of-the-room than your internal voice. This persona lives at the Project level, not in your top-level Customize — because it only applies to specific work.
What changes from your default
- Warmth dial up — not gushing, but acknowledging the human on the other end
- Pace dial down — fewer punchy short sentences, more flowing prose
- Stakes dial up — be more careful about what gets said, what gets implied, what gets promised
- Confidence dial calibrated — direct on facts, careful on commitments
Where this persona lives
Project Instructions for any customer-facing Project. NOT in your top-level Customize. Why: if you put "warm and customer-facing" in your Custom Instructions, it bleeds into your internal work — your Slack messages become slightly mushy, your team memos lose their punch.
The customer voice template
Project Instructions — Customer-facing work
CONTEXT: This Project handles customer-facing communication. Audience is the customer's primary contact — usually a manager or director. Sharp but time-pressed. They read on mobile. VOICE LAYERED ON DEFAULT: - Open with their first name on its own line (humanizes immediately) - Reference their specific situation in the first sentence (proves we read their context) - Default length 80–150 words (mobile reading) - Lead with the substance, not preamble - End with a direct reply path to me WARMTH RULES: - "I appreciate you bringing this up" instead of "Thank you for reaching out" - "Let me get this right" instead of "I'd like to understand" - Acknowledge frustration directly if present — don't paper over it NEVER (in addition to global never-dos): - "We apologize for any inconvenience" - "Just to circle back" - "Per my last email" (even if accurate) - Promise specific dates without checking with engineering/ops first ESCALATION: If the customer mentions legal, attorneys, "considering alternatives," or any compensation issue — stop, flag, route to me. Don't draft a response.
The test
Inside the customer-facing Project, send a real customer scenario: a complaint, a renewal question, a feature request denial. Read the draft. Does it sound warm without being sycophantic? Direct without being curt? Does it match what you'd send if you wrote it from scratch?
Your turn — 10 minutes
Write your customer-facing persona's Project Instructions. Adapt the template above to your specific audience and situation.
Your strategic / board voice.
For high-stakes audiences who don't have time for the conversational tone. Board memos. Executive briefings. Investor updates. Anything where the reader's attention budget is measured in seconds.
What changes from your default
- Density up significantly — every sentence carries weight
- Examples and narrative cut — readers infer from context; they don't need scaffolding
- Headlines lead everything — top-of-document, top-of-section, top-of-paragraph
- Numbers replace adjectives — "down meaningfully" → "down 14%"
- Recommendations precede reasoning — the call, then the why
The strategic voice template
Project Instructions — Board / Executive work
CONTEXT: This Project handles board memos, executive briefings, investor updates. Audience is busy senior people who read at 9pm between meetings. They want my conclusion first and my reasoning available if they need it. VOICE LAYERED ON DEFAULT: - Every memo opens with a one-sentence headline that is the takeaway - Every section opens with a one-sentence headline that is the takeaway - Every paragraph opens with the most important sentence - No narrative scaffolding ("As we discussed..." "You'll recall..." "It's worth noting...") - No hedging language ("we believe," "it seems," "it appears") — make the call FORMAT: - Default 400–600 words for memos - Use bold sparingly — only on the single most important phrase in each section - Numbers as raw figures with one-line context. "Revenue +$320K week-over-week (+4.1%)" not "Revenue increased significantly" - If a recommendation has a real downside, name it in the same paragraph as the recommendation, not later NEVER: - Bury bad news. Name it in the headline. - Use the words "robust," "leverage," "strategic," "synergy" - End a memo without a single clear ask or decision needed LENGTH DISCIPLINE: Default to shorter. If draft exceeds 600 words, ask whether the audience truly needs the additional context. They almost never do.
The board voice in 3 sentences
"Pipeline +$320K week-over-week (+4.1%) — best week of the quarter, but loss patterns suggest a competitive pricing shift worth our attention. Recommend we run a pricing review by Q3 end and adjust before October renewals. Need your call on whether to involve external benchmarking."
Three sentences. Headline metric. The complication. The recommendation. The ask. That's the entire pattern for strategic-voice writing.
Your turn — 10 minutes
Write your strategic-voice Project Instructions. Use the template. Reference one or two specific examples of high-stakes work you do (or wish you did better).
Switch voices mid-conversation.
The Project approach handles persistent voice changes — open the customer Project, get the customer voice. But sometimes you want to switch within a single conversation. The trigger-phrase pattern handles that.
The trigger phrase pattern
You define short phrases in your Custom Instructions that tell Claude to shift voice. Then you use those phrases inline as you work. The mechanism: Claude reads your Custom Instructions every turn, sees the trigger definitions, and applies whichever one is active.
Setting up the triggers
Add this to your Custom Instructions at the bottom (after your default voice rules):
VOICE SWITCHING: When I write "customer voice on" — switch to the customer-facing voice: warmer opening, length 80–150 words, "I appreciate" instead of "Thank you," direct reply path at the end. Stay in this voice until I write "voice off" or "back to default." When I write "board voice on" — switch to the strategic voice: headline-first paragraphs, numbers with one-line context, no narrative, recommendation precedes reasoning, 400–600 words max. Stay in this voice until I write "voice off" or "back to default." When I write "voice off" or "back to default" — return to my default work voice.
In practice
You're in a regular conversation. You need to draft a customer email. You type:
customer voice on. Draft a reply to Jenna at Riverside — she's asking why we missed her Q3 onboarding milestone. The miss was on us (engineering delay on a feature she needed). Acknowledge directly, propose a recovery plan, ask for a 15-min call this week.
The output uses the customer-facing voice. You read it, edit if needed, send. The next message in the same conversation — without any trigger — goes back to your default work voice.
When to use Projects vs Triggers
- Use a Project when most of your work in this domain happens here. Customer success work happens dozens of times a week — give it a dedicated Project.
- Use a trigger when you need a voice occasionally but not enough to justify a separate Project. Board memos written quarterly — trigger is fine. Customer emails written hourly — Project.
The discipline
Keep the trigger list short — 2 or 3 max. More than that and you'll forget the phrases. The strength of triggers is they're frictionless to use; that frictionless quality dies the moment you have to look up which phrase activates which voice.
The "never do" list — across all personas.
Personas change voice. Rules don't. Every persona you've built inherits a set of universal "never do" rules — the things that should be true regardless of context. This page is how to maintain that list.
What belongs in the never list
Two categories:
1. Voice rules you hold across all contexts
- Specific words/phrases you refuse to use
- Punctuation rules (e.g., no em-dashes used decoratively)
- Opening lines you refuse to use (e.g., "I hope this finds you well")
- Closing patterns you refuse to use (e.g., "Thanks in advance")
2. Safety rules that prevent real damage
- Never send external email without my review
- Never quote specific pricing without checking the current pricing matrix
- Never make claims about engineering timelines without verification
- Never reply to legal/regulatory inquiries — escalate immediately
What does NOT belong in the never list
- Things that depend on context (those go in persona-specific instructions)
- Things that are "would be nice to avoid" rather than "must avoid"
- Vague aspirations ("never be boring") — be specific or skip
Where the list lives
The voice rules go in your top-level Custom Instructions (so they're enforced across every conversation in every Project). The safety rules can live either there or in specific Project Instructions where they apply.
Maintaining the list
The "never do" list grows over time. Every time Claude produces output that makes you wince, ask: "Is this a one-off, or should I add a rule?" If it's the second time the same phrase has shown up, it's a rule.
Conversely: review the list once a quarter. Anything that's become irrelevant? Anything that was added in a moment of frustration but isn't actually a problem? Prune.
The complete starter list (steal this)
UNIVERSAL NEVER-DOS: WORDS/PHRASES: - "leverage" (as a verb) - "synergize," "synergy" - "unlock" - "circle back" - "at the end of the day" - "moving forward" (as a transition) - "robust" (as a quality descriptor) - "I hope this finds you well" - "Per my last email" - "Just to circle back" - "Thanks in advance" PUNCTUATION: - Em-dashes used decoratively in every paragraph — fine occasionally, not as a tic - Exclamation points outside genuinely celebratory contexts - Ellipses to imply something I haven't said PATTERNS: - Sentences that start with "It's not just X — it's Y" - The "5 tips for..." or "10 ways to..." listicle template (unless I specifically ask) - Recommendations hedged behind three qualifiers — pick one and own it - Burying bad news under wins in the same paragraph SAFETY: - Sending external email without my review - Making specific date commitments without checking - Quoting prices without referencing the current pricing matrix - Responding to legal language — always escalate
Your turn — 10 minutes
Build your own never-do list. Start with the template above. Add 3–5 things specific to your work or your pet peeves. Cut any items from the template that don't actually bother you.
Customize module — done.
You have a voice profile, three configured personas, a trigger system for switching between them, and a universal never-do list. Together, these make every Claude conversation start already sounding like you.
What you walk away with
The voice audit.
Five samples of your real writing produced a profile that describes how you actually sound — not how you think you should sound.
Three configured personas.
Default work voice (Custom Instructions). Customer-facing voice (Project Instructions). Strategic/board voice (Project Instructions). Each one a deliberate, separate configuration.
Trigger-based switching.
Short phrases that activate persona switches mid-conversation. Two or three triggers max — kept frictionless on purpose.
The never-do list.
Universal rules inherited by every persona. Voice rules and safety rules together. Pruned quarterly.