Full Idea
Dennett maintains that a system has states with representational content if we are able to predict its behaviour reliably and voluminously by adopting the intentional stance toward it.
Gist of Idea
States have content if we can predict them well by assuming intentionality
Source
report of Daniel C. Dennett (True Believers [1981]) by Peter Schulte - Mental Content 5
Book Reference
Schulte,Peter: 'Mental Content' [CUP 2023], p.44
A Reaction
Dennett himself seems happy to thereby attribute representational content to a chess-playing computer. This sounds like a test for content, rather than explaining what it is. Not promising, I think.