If a description describes one embodiment but the claim is very broad that does not limit to that embodiment, what will be actually protected? Any embodiment under the broad claim or the specific embodiment in the description? To give an example, a transdermal biosensor using an enzyme is described but the claim is generally a sensor that uses enzymes. What will be protected?
If you are talking about an issued U.S. patent there is a reasonable chance that, if it is enforced, a court will interpret a claim more narrowly than its actual words.
There is one truism of claim interpretation that you don't import the specification into the claims. On the other hand a second truism is that the claim needs to be enabled across its scope and needs to be supported by the specification. Some judges are saying, in effect, "independent of the breadth of the words of the claim, I know what the inventor really invented and it is the preferred embodiment."
One expert has written a book about this called The Rules of Patent Drafting: Guidelines from Federal Circuit Case Law. I am not linking to Amazon since it is over $200 but the author has written about it elsewhere.