Speaking to Gazzetta dello Sport, Capello praised the club's business over the summer and identified Jones as the final piece of a squad he now considers ready to defend the title.
"Was he the player that was missing? I'd say yes. Something with real substance was missing in midfield. Jones brings physicality and personality.
"On paper it all makes sense, the club have strengthened the team well and this signing is the ideal finishing touch.
"Of course we'll need to wait for him to settle into the new team to judge him fully. But the feeling is positive."
Jones will formally become the fifth arrival of Inter Milan's summer, following the permanent additions of Ivan Provedel, John Stones and Djed Spence, and the activation of Aleksandar Stankovic's buy-back clause from Club Brugge.
He landed in Milan on Thursday evening and is due to undergo his medical on Friday morning before signing his contract with the reigning Serie A champions, meaning he is unlikely to be involved when Cristian Chivu's side open the new campaign at home to Monza. He should, though, be available for Inter's second fixture of the season, along with Spence, who has trained separately in recent days to build up his fitness.
While Jones completes the formalities in Milan, Chivu will hold his own pre-match press conference at Appiano Gentile ahead of the visit of newly promoted Monza, coached by Ivan Juric.
Capello also gave his verdict on the wider title race, naming Inter clear favourites.
"On paper Inter shouldn't have any rivals, they'll just need to be careful not to lose focus in matches that look easy. Behind them, the team best prepared, partly because they haven't changed anything, is Roma. Napoli are at the same level as Roma, but it remains to be seen how quickly the group gels with what Allegri is asking of them.
"Juventus are working well, we'll see with time whether they become a team to consider, but they can't be ruled out. Milan need to be watched too, though the new project is starting the right way. Their season will depend on how quickly Amorim gets into the players' heads: that's the most important thing."