The claim that Pete Hegseth is using his Tuesday gathering of military personnel to impose a loyalty test requiring a direct pledge to Trump rather than the USA is misleading because available sources confirm a large, unusual meeting of military leaders focused on topics like 'warrior ethos' and organizational changes, but there is no verified evidence that a loyalty pledge to Trump is being demanded.
Sources have confirmed that Pete Hegseth is using his Tuesday gathering of military personnel to impose a loyalty test, where they will be required to directly pledge to Trump, rather than the USA.

Pete Hegseth summons hundreds of generals to rare, urgent meeting: Confusion sweeps through ranks - Daily Mail Online
Source: dailymail.co.uk
Key Evidence
CNN reports the meeting is for discussing 'warrior ethos' and departmental changes without mentioning loyalty pledges.
cnn.comcnn.comHegseth’s surprise gathering of top military brass is to deliver speech on...
The New York Times and The Washington Post describe the meeting as unusual but do not confirm any loyalty test.
nytimes.comnytimes.comHegseth Is Said to Have Summoned U.S. Military Brass From Around the Globe
washingtonpost.comwashingtonpost.comHegseth orders rare, urgent meeting of hundreds of generals, admirals
An opinion article warns about potential risks of politicizing the military but does not provide evidence of an actual loyalty oath requirement.
thehill.comthehill.comTrump and Hegseth want to turn the military into a tool of personal loyalty
What the Evidence Shows
Multiple reputable sources report that Defense Secretary Pete Hegseth has summoned hundreds of top military officers to a rare and urgent meeting in Virginia. The stated or inferred purposes include delivering speeches on 'warrior ethos,' discussing the reinvention of the Department of Defense, and addressing recent personnel changes such as firing top officers and reducing four-star ranks.cnn.comcnn.comHegseth’s surprise gathering of top military brass is to deliver speech on...
nytimes.comnytimes.comHegseth Is Said to Have Summoned U.S. Military Brass From Around the Globe However, none of these sources provide verified confirmation that attendees are being required to take a loyalty oath directly to former President Donald Trump instead of the United States. Opinion and editorial pieces express concerns or fears that the military might be turned into a tool of personal loyalty to Trump, but these are speculative and interpretive rather than factual reports. Social media discussions reflect confusion and debate within military communities but do not provide authoritative evidence supporting the claim. Official statements from the White House downplay the meeting's significance without mentioning any loyalty tests.+6 more
In summary, while the meeting is unusual and has raised questions and concerns about its intent, no credible source confirms that a loyalty pledge to Trump is being imposed on military personnel at this event. The claim appears to conflate speculation or opinion with verified fact.