Promising a “once in a generation” rapprochement with Germany, Britain’s prime minister, Keir Starmer, on Wednesday pushed his plan to boost post-Brexit ties across Europe.

But while his visit to Berlin generated warm rhetoric and underscored a change of tone from the previous Conservative government’s approach, little detail was forthcoming on how repairing relations with European member states would bring about actual policy change.

After talks with the German chancellor, Olaf Scholz, Mr. Starmer said he expected that a new Anglo-German treaty, covering defense, technology, business and culture, would be struck by the end of the year as part of a broader reset of relations with the European Union.

Even as the prime minister smiled and said he was “delighted” to be standing alongside Mr. Scholz, he did not commit to specific policy changes and reiterated his election pledge that Britain would not rejoin the bloc’s economic structures. He said that Britain had “no plans” to agree a mobility scheme — of the type favored by Germany — that would help young Britons and their European counterparts cross the channel to work, though he did not rule out that prospect when asked later by reporters.

Britain’s 2016 referendum, in which the country voted by a narrow majority to leave the European Union, plunged it into a sustained political crisis and raised tensions with its member states. In the years that followed, fractious Brexit negotiations under the pugilistic prime minister Boris Johnson torched ties with many European capitals. His short-lived successor, Liz Truss, once pointedly refused to say whether the French president, Emmanuel Macron, was a friend or enemy.