Detailed answer
Summarize what someone can learn or do on the particular page.
Keep it accurate and useful rather than listing repeated keywords. Search engines may choose another snippet depending on the query. A description helps describe the content but cannot substitute for useful information on the page itself.
Example
<meta name="description" content="Learn how HTML labels connect to inputs, with working examples and fixes for missing accessible names.">
Understanding the behavior
A meta description should summarize the page's actual answer or purpose in natural language. Avoid claiming information that the page does not contain. A distinctive summary is more useful than a boilerplate keyword list repeated across every discussion.
Practical implementation notes
Check the rendered head for a single description. Search snippets can vary by query and may use page text instead, so there is no fixed character count that guarantees a particular appearance.
How to check it
Rewrite it as a useful summary of the actual answer and inspect the head markup.
Expected result
The description is specific, though search engines may choose another snippet.
Watch out: Do not treat a meta description as a guaranteed search snippet.
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