AI Max Text Guidelines: Control Generated Copy With Clear Instructions

Know which copy the setting affects

Text customization generates headlines and descriptions using inputs such as your existing ads, keywords and website. Generated text joins the assets Google can use in responsive search ads. Keeping old promises on the website while trying to prohibit them in ads is therefore a poor starting point.

Imagine a service business that once offered same-day appointments but no longer does. First remove the stale offer from the pages customers and the system can encounter. Then inspect existing advertising and add a clear restriction against the discontinued promise. A guideline is an additional control, not a repair for contradictory source material.

The text-guidelines beta is campaign-level and requires text customization. It applies to text-customization assets, not every manually authored ad. Newly added rules also affect existing Google-optimized text: nonconforming assets can stop serving and be marked removed.

There is also a transition to know about. In its April 2026 AI Max announcement, Google introduced AI Brief and said existing text guidelines move into its messaging guidelines when an advertiser starts using it. The announcement describes an English-language rollout for Search first, with other campaign types following. Check which interface your account has; this guide explains the text-guidelines controls, not every AI Brief feature.

Choose the control that matches the problem

Google supports two controls in text guidelines:

Term exclusions: up to 25 exact words or phrases per campaign. They ignore letter case but are language-specific.

Messaging restrictions: up to 40 requirements about concepts or style, applied across asset languages.

Instructions must be definite. These controls do not target search queries or guarantee returns. In campaign Settings → AI Max, find Add text guidelines under Asset optimization, with text customization enabled. Copied guidelines are independent, not a synchronized master list.

The examples are starting points, not a reusable policy for every advertiser. Before adding one, ask whether it describes your actual offer. A subscription with a genuine lifetime option should not inherit another company's prohibition.

Specificity does not mean writing a page of instructions. One clear requirement is easier to inspect than a paragraph mixing tone, discounts, locations and product claims. Keep separate concerns separate, and avoid filling every available slot simply because it exists.

Here are hypothetical examples of how an advertiser might make an instruction more useful:

Read the ad as a customer would

A technically compliant sentence can still leave the wrong impression. Read the message beside its destination: what does a reasonable visitor expect to get, pay or do next? Ask someone unfamiliar with the campaign to explain that expectation in their own words. Their answer may reveal a gap that a prohibited-word list cannot.

AI Max's URL expansion and text customization work together. When a different URL is selected, pinned responsive-search-ad assets may not be used. Do not assume pinning alone guarantees that a required phrase will accompany every expanded destination. Where exact wording is essential, review whether the chosen automation settings are appropriate.

Google's setup guide explains the asset settings and their dependency: switching text customization off also disables final URL expansion. Treat that as a campaign behavior change, not merely a way to hide one awkward headline.

The right remedy depends on what failed. An outdated page needs a content fix. A misleading generated phrase needs an asset or guideline correction. An unsuitable destination needs attention to URL controls. Changing all three together may solve the symptom while making the original cause harder to understand.

Check the result, not just the saved instruction

After saving, inspect generated assets and their status. Google's reporting documentation identifies customized assets through the Added by value Google AI and provides removal controls. Check the actual wording; the presence of a saved rule is not proof that every customer-facing message is suitable.

Do not wait for a performance trend before addressing a false offer. Conversely, do not assume that removing a phrase will improve cost per acquisition. Accuracy and effectiveness are related questions, but they are not interchangeable.

If click-through rate rises while qualified enquiries fall, investigate the query mix, destination and conversion definitions before blaming a single headline. Assets serve in combinations and under different conditions. The more useful question is what expectation the ad created and whether the business fulfilled it, not which isolated sentence gets credit for the entire campaign.

Keep a few representative examples of the issue and the corrected instruction. That is usually more useful than a recurring spreadsheet in which every asset must be marked “allow, block or revise.” Use a formal review only where the business actually needs it.