Ask an agency how it reviews copy and the answer usually involves a person reading a page. A copywriter checks their own draft, an editor reads it again, the strategist skims it for positioning and the client marks up whatever catches their eye. Each of those reads is useful, and every one of them happens one page at a time.
That works when the problem lives on a single page. The trouble is that the voice problems clients notice most often do not. The homepage promises one thing and the pricing page says another. The new service pages sound plain and confident, while the location pages written three years ago still sound like a law firm. Nobody wrote a bad page. The site simply stopped agreeing with itself, and no single-page review was ever going to see it.
This guide covers the part of brand voice work that agencies carry and most voice advice ignores: keeping one client's voice consistent across dozens of pages written by different people at different times, while doing the same for every other client on the books. It explains why client sites drift, how to give each client a standard that can settle an argument, how to review a site rather than a page, and when to check so that drift is caught before the client finds it.
We build software that reviews websites against a brand voice, and agencies are one of the groups we built it for. Everything below works with a spreadsheet and a careful reader.
Why client sites drift faster than your own
An in-house team has one voice to protect and usually the same few people writing it. An agency has neither advantage. The copy on a typical client website was written in layers: launch copy from the original project, pages added later by the client's marketing coordinator, a services section rewritten during a rebrand, articles from a freelancer, and more recently a batch of pages drafted with AI and lightly edited. Each layer was reviewed when it went live. Nobody reviewed how the layers sat together.
Agency workflows add their own pressure. Design and development change copy late, when a headline is shortened to fit a layout or a section is cut in staging. Client feedback tends to arrive as edits rather than notes, and those edits rarely follow the guide. Retainers rotate writers, and handover documents describe the voice without carrying the judgement of the person who understood it. None of this is negligence. It is how work behaves when it passes through many hands across many accounts, and it means drift is the normal state of a client site rather than an exception.
Page problems and site problems
Most copy review catches page problems: a vague headline, a weak call to action, a paragraph that could belong to any competitor. Our guide to auditing website copy line by line covers those in detail, and they matter. Agencies also need to catch a second kind of problem that only exists between pages, and it tends to do more damage, because visitors read across pages even when reviewers do not.
Take a running example. Harbour Physio is a fictional client with four clinics and a 34-page website. The homepage was rewritten last year in a warm, direct voice, and here is how it handles booking:
Book online in about two minutes. You don't need a referral, and if you're not sure which appointment to choose, pick “Initial assessment” and we'll sort out the rest.
The Bondi clinic page was written three years earlier and has not been touched since the rebrand. Here is the same topic on that page:
Patients are advised to contact reception to arrange an appointment. A referral from a general practitioner may be required for certain services.
Each page reads acceptably on its own. Together they contradict each other on a fact (online booking or a phone call, referral or no referral) and on voice (a person talking to you, or an institution issuing notices). A visitor who lands on the Bondi page from a map search meets the old clinic. One who starts on the homepage and clicks through meets two different businesses.
Site problems usually fall into three groups. Factual conflicts are the most urgent: prices, processes, service lists or guarantees that disagree. Promise conflicts come next, where one page commits to something another page quietly walks back, such as “no waitlist” on the Harbour Physio homepage and an FAQ that mentions a two-week wait for new patients at two clinics. Voice conflicts are the slowest to notice and the most common, with pages using different pronouns, levels of formality or degrees of certainty for the same reader. All three need someone looking across the site, which is exactly the step a page-by-page process leaves out.
Give every client a standard that can settle an argument
Before anyone can say a page is off-voice, there has to be something to measure it against, and for many clients there is not. Some arrive with a forty-page brand book that says almost nothing testable. Others have no guide at all, only a website that has been drifting for years. In both cases the agency's first job is to turn whatever exists into a short set of rules that a sentence can pass or fail.
Our brand voice guide explains how to write those rules, and the principle carries straight into client work: replace adjectives with decisions. “Warm and approachable” will not settle a disagreement between your writer and the client's practice manager. “Address the reader as you, explain clinical terms the first time they appear, and never tell a patient what they are advised to do” will. For Harbour Physio, that last rule alone would have flagged the Bondi page.
When a client has no guide, infer one from their strongest pages, label it as provisional and ask the client to confirm it before treating it as the standard. We cover that process in inferred vs. documented brand voice. The labelling matters more on agency work than anywhere else, because an inferred voice presented as an agreed one is how agencies end up defending a standard the client never signed off.
Keep each client's standard separate and specific. It is tempting to build one house checklist and run every client through it, but a sentence that suits a founder-led software company can be wrong for a healthcare provider whose readers need caution and proof. The review criteria can stay the same across clients. What counts as passing should change with the client.
Review the site, not the page in front of you
With a standard in place, the review needs a different shape. Start with an inventory of every live page grouped by type: home, services, locations, pricing, about, FAQ and articles. Then read across each group before reading down any single page. Four location pages read side by side will show inconsistencies within minutes that could take hours to notice one at a time, because the differences only appear in comparison.
Next, pick the handful of facts and promises that appear on several pages, such as how to book, what it costs, who it is for and what the client guarantees, and trace each one across the site. Log every version you find in a simple table:
| Topic | Page | What it says | Conflicts with |
|---|---|---|---|
| Booking | Homepage | Book online, no referral needed | Bondi and Manly pages: call reception, referral may be required |
| Waiting times | Homepage | No waitlist | FAQ: two-week wait for new patients at two clinics |
| Voice | Location pages | Third person, formal (“patients are advised”) | Rest of site uses “you” and plain language |
This table is often the most useful thing you will hand the client, because it turns “the site feels inconsistent” into a list of decisions. Someone has to decide whether referrals are needed, and that decision belongs to the client, not the copywriter. Once it is made, every conflicting page has a clear fix and the edits can be briefed in an afternoon.
Finally, give the pages nobody is working on the same attention as the ones in the current scope. Drift concentrates on old pages because they are the ones no one opens. A rebrand that rewrites the homepage and services but leaves thirty older pages untouched has created a two-voice website, and the client will usually be the one who notices.
Separate the first pass from the judgement
Much of an agency's review time goes on finding problems rather than deciding what to do about them. Spotting vague claims, unsupported superlatives, generic phrasing and pronoun shifts across thirty pages is repeatable work. Deciding whether the client should soften a promise, or which of two conflicting facts is true, is not. Splitting the two lets senior people spend their time on the calls that need them.
The first pass should apply the same criteria to every page so that findings from different reviewers can be compared, and it should point at sentences rather than impressions. Compare two pieces of feedback on the same Harbour Physio page:
Before: The Bondi location page feels a bit dated and might need a refresh.
After: Four sentences on the Bondi page conflict with the rest of the site. Two describe phone-only booking, one says a GP referral may be required, and one uses “patients are advised”, which breaks the plain, second-person rule in the voice standard.
The second version is no less human. It is easier for the client to agree with, easier for the writer to act on and easier to check afterwards. That last part is the step agencies most often skip. Once the edits are live, re-read the changed pages against the same criteria to confirm the problem is actually gone rather than assuming it is.
Check at the moments drift happens
A one-off audit fixes today's site and says nothing about next quarter's. Client sites drift at predictable moments, so it makes sense to build checks around those moments rather than around the calendar alone.
Before launch, review the assembled site after design, development and final edits have all had their turn, since late changes are where launch copy most often breaks. During a rebrand, look for pages still using the old voice or the old positioning, because rebrands rarely reach every page. Before handover, run a full pass so the client inherits a consistent site and a written standard rather than an undocumented one. After any batch of AI-drafted pages, check them against the client's standard specifically, since AI drafts tend to be fluent, generic and confidently wrong about details only the client knows. On a retainer, re-check changed pages regularly so drift is caught within weeks rather than discovered at the next annual review.
For the audit itself, our guide to running a brand voice audit walks through the process step by step. The agency version is the same audit, run per client and scheduled around those moments, with the conflict table added on top.
Making it repeatable
Keeping a client's voice consistent comes down to a few habits: writing each client's voice as a standard someone can test, reviewing the whole site rather than the page in front of you, and checking at the moments drift tends to happen. Good writers help, but most of this is process, and most of the process can be repeated for every client you look after.
Revisi handles the repeatable part. It scans each client site against that client's own voice profile, ranks the pages that need attention, flags conflicts between pages and points to the sentences behind every finding, with re-scans and scheduled monitoring to catch drift between reviews. Your team keeps the judgement. If you look after several client sites, tell us about them and we will set your agency up.