David Cameron hopes to get agreement for his proposed renegotiation at a meeting of EU leaders on 18 February, paving the way for a future referendum.
Draft conclusions of the summit, issued in advance, state any deal would be “fully compatible with EU treaties”.
No more detail is given about the final agreement still being negotiated.
The two-day meeting is a crucial moment in the debate over the UK’s future in the EU. Mr Cameron requires the approval of all 28 EU members for a draft package of reforms to the UK’s membership outlined earlier this month.
If he secures it, he is expected to proceed with an in-out referendum on the UK’s membership by the end of June.