Use the summary to create context
A summary is useful when a reader needs help connecting your experience to the role in front of them. That can be true when you have a long work history, a clear specialty, or a career transition that would otherwise take a few lines to understand.
It is not a mandatory ceremony. If the opening only says that you are motivated, hardworking, or seeking an opportunity, the space is probably better used for evidence elsewhere.
Name the relevant pattern
A practical summary usually names your professional area, the strongest relevant experience, and one or two qualifications the role actually values. It should make the reader curious to scan the experience section, not repeat it line by line.
Write it after you have tailored the rest of the resume. At that point, you know which pattern the page is trying to show.
Keep it short enough to scan
One line can work as a headline. Two or three concise sentences can work as a summary. Anything longer starts to compete with the experience section and asks the reader to work too hard before seeing your proof.
Check the language against the job posting, then remove anything that is broad enough to describe almost anyone.
Sources consulted
This guide is an original synthesis of the following career guidance. Read the source material for its full context.