I have either worked in government or for government my entire adult life. I’ve worked daily with the DoD, DoS, and the intelligence community every day for the last 20 years.
The days of Tip O’Neil and Ronald Reagan sitting on opposite sides of almost every possible issue, but remaining cordial and professional and actually communicating have long since ceased to exist in American politics.
If you work for or with congress in any capacity you know that they do indeed get briefed after the fact when military operations or offensive intelligence operations occur. Sometimes it Is only limited people on select committees due to security clearance requirements and need to know… but there are very clear and very specific rules about who gets briefed and when… and those rules are very rarely broken… when they are broken we end up with National/International scandals like Iran/Contra.. people lose jobs, people go to jail, people don’t get re-elected..
It should be noted that historically it’s members of congress that break the rules with far more frequency than the executive branch or any of the cabinet appointees..
Trump himself won’t be briefing congress… but senior cabinet officials will at a minimum be briefing committee chairs if/when something happens..