Three days after U.S. President Donald Trump announced a deal with Mexico to stem the flow of migrants at the southern border, the two countries appear unable to agree on exactly what’s in it. Stung by criticism that the agreement mostly ramps up border protection efforts already underway, Trump on Monday hinted at other, secret agreements he says will soon be revealed. “We have fully signed and documented another very important part of the Immigration and Security deal with Mexico, one that the U.S. has been asking about getting for many years,” Trump wrote Monday, saying it would “be revealed in the not too distant future.” Not so, said Mexican Foreign Secretary Marcelo Ebrard, holding up a paper and pointing to the previously announced details. He told reporters the two countries agreed on two actions made public Friday and said if those measures didn’t work to slow migration, they would discuss further options. “There is no other thing beyond what I have just explained,” he said. The episode revealed the complicated political dynamics at play as Trump and Mexican President Andrés Manuel López Obrador tussle over who made out best in the agreement hashed out under Trump’s threat of new tariffs on Mexico. Trump appeared eager to declare his negotiation tactics successful, even as he tried to hype the deal with made-for-TV drama and invented measures, sparking questions and confusion. Mexico’s leaders showed they weren’t willing to play along. The White House did not respond to inquiries about Trump’s tweets….