A meta description is HTML text that summarizes a page and may be used as a search-result snippet; Google can instead select visible page text.
For example, <meta name="description" content="Compare repair options, costs and booking requirements."> is a candidate summary, not a command. Google can choose visible wording that better matches a query.
What a meta description does
The description meta tag gives a concise candidate summary of a page. Google can use it in a result snippet, but it can generate a different snippet from visible page content when that better matches the query. It is therefore an editorial and technical input, not a promise about what searchers will see and not a switch for rankings.
Write it for the page’s actual purpose. A product category can state the selection and decision context; a how-to page can state the task and result; a policy page can state the scope. Reusing one boilerplate sentence across pages makes it less useful to readers and offers little page-specific context.
Build it from the page
Read the final title, H1, first explanatory section and any facts that can change. Capture the page’s distinct answer in one sentence without inventing price, availability, dates or outcomes. Avoid quotations that merely repeat the title, a stack of query terms, and calls to action that say nothing about the destination.
Then inspect the rendered HTML rather than a CMS field. Check that one intended description is present, that templates do not append a conflicting tag, and that the canonical URL points to the page you described. A description cannot resolve duplicate pages, redirects or a mismatch between a page’s promise and its visible content.
Review the snippet separately
Search-result snippets vary by query, device, search feature and time. When reviewing a result, record the query, displayed title, displayed snippet, target URL and date. If Google selected a different passage, first ask whether the page contains a clearer answer to that query; changing the tag may not be the right repair.
Use Search Console to view queries and clicks in context, not as an instruction to rewrite every low-CTR description. A low rate can reflect ranking, intent, ads or an answer directly in the result page. The technical check is whether the tag is accurate and specific; performance interpretation needs a comparable segment.
Frequent mistakes
Do not require a fixed character count, stuff keywords, write descriptions before the content exists, or claim that a tag guarantees a rich result or a particular snippet. The durable standard is one truthful, page-specific summary that remains useful if search engines choose it and harmless if they do not.