The idea may be to take stock of the new papacy at its six-month mark, though the unknowns about the encounter outnumber the certainties.
At this stage, it's not clear what topics may come up, who's going to speak or in what order, and whether the pope may use the occasion to announce further personnel moves or structural changes.
The gathering is sandwiched between two key developments -- the Aug. 31 announcement of Italian Archbishop Pietro Parolin as the Vatican's new Secretary of State and the looming Oct. 1-3 meeting of the council of eight cardinals created by Francis to advise him on church governance.
As a result, it may be a chance for the pope to solicit feedback on decisions already made and to talk about what's still ahead.
In the meantime, the following are three preliminary observations about the significance of this meeting.
Benedict XVI, for instance, convoked one in 2006 to discuss relations with the traditionalist Society of St. Pius X and another in 2011 to talk about religious life.
Sometimes these sessions blend significant policy deliberations with fairly minor housekeeping matters.
In 2003, for instance, John Paul II called such a meeting both to discuss a potentially explosive turn in Catholic/Orthodox relations and to talk about how to fix the problem of Vatican employees clocking in late for work.
An open-ended gathering is, therefore, something of a novelty.
Arguably, it expresses a desire for a more collegial and collaborative mode of governance.
Especially if it's not just a one-off event, the meeting may also respond to oft-voiced frustration that the various Vatican departments don't communicate well among themselves, resulting in both duplication of effort and, at times, the impression of working at cross-purposes.
Rather than an occasion to announce reform, in other words, one could argue that the meeting itself is a reform.
Second, it's telling that the letter convoking the meeting came not from the Vatican's Secretariat of State but the Prefecture of the Papal Household.
Traditionally, the Secretariat of State has been the Vatican's "super-dicastery," meaning the office that coordinated and, to some extent, supervised the work of all the others.
As part of that picture, when department heads were brought together in the past, the Secretariat of State ran the show.
Pope Paul VI's 1967 document on the Roman Curia, Regimini Ecclesiae universale, anticipated that interdicasterial meetings would be called not by the pope but by the Cardinal Secretary of State in order "to coordinate everyone's work, to provide information and to receive suggestions."
(A longtime official of the Secretariat of State under Popes Pius XI and Pius XII, it was Paul VI who cemented its role as the Vatican's most important agency of government.)
Under Francis, however, there are signs that the Secretariat of State may be having its wings clipped.
The creation of the new council of cardinals suggests that it, not the Secretariat of State, will be the pope's most important sounding board, and because Francis is a leader who takes the reins of government very much in his own hands, he's less dependent upon the Cardinal Secretary of State to serve as a sort of "vice-pope."
The fact that Francis is bringing together the department heads himself is perhaps a small way of suggesting that they'll report directly to him rather than having to navigate the traditional gatekeepers in the Secretariat of State.
Italian Cardinal Tarcisio Bertone, the current Secretary of State, will take part in the meeting, but especially since he's now a lame duck, he's not expected to play a major part in the proceedings.
Third, it's also significant that Francis has convoked this gathering just before the meeting of the council of cardinals, since many in the Vatican privately have raised questions about what exactly that body is going to do and how it's going to work.
Given that a major part of the council's mandate is to advise the pope on Vatican reform -- which could include, for instance, eliminating or consolidating some departments, as well as changing procedures for how budgets are allocated or how personnel assignments are determined -- it's naturally created anxiety inside the system.
In that regard, Francis may need to do some hand-holding, reassuring veterans that they'll have what the Italians call una voce in capitolo, meaning a voice in how things unfold.
Francis may want to shake things up, but he also needs people with experience to help implement whatever reform he intends to launch.
Francis followed that logic in naming a veteran Vatican diplomat as his new Secretary of State, and perhaps this meeting is another acknowledgment that an outsider pope has to take special care to bring the insiders along.
In terms of what might come up, Italian media reports have speculated that Vatican insiders may want to discuss some of Francis' personnel moves.
Questions have been raised both about a cleric named by the new pope as his delegate to the Vatican bank, Msgr. Battista Ricca, accused in the Italian press of engaging in homosexual affairs when he was a Vatican diplomat in Uruguay from 1999 to 2004, as well as Francesca Immacolata Chaouqui, a laywoman named to a new body studying the Vatican's financial and administrative structures.
Not only has Chaouqui's Twitter account revealed several messages critical of Bertone and applauding the journalist who created the Vatican leaks affair, but recently a few racy pictures of the 30-year-old business professional on YouTube (since removed) have created a minor Italian sensation.
The popular magazine Panorama recently carried a piece on Chaouqui under the headline, "The sexy bomb who embarrasses the Vatican."
To date, Francis has given no indication of withdrawing either appointment. He defended Ricca directly during his airborne news conference on the way back to Rome from Brazil on July 28, saying that a preliminary investigation did not produce any confirmation of the charges against him.
The meeting also unfolds against the backdrop of the Vatican's ongoing full court press against Western military strikes in Syria, so the meeting creates an opportunity to talk about where that effort may go in the days to come, and what role the Vatican might play in the aftermath if the strikes occur.