Cognitive and metacognitive prompts are a central support procedure in eHELp a computer-based environment that supports the writing of learning protocols. In order to investigate the effectiveness of adapting prompts, 79 students revised a learning protocol in eHELp either supported by prompts that were adapted on the basis of the results of an integrated learning-strategy questionnaire or a meta-knowledge test, respectively, by randomly selected prompts, or without any support. Adaptive prompts improved the quality of the learning protocols and fostered the acquisition of declarative knowledge and deep understanding, irrespective of the applied diagnostic instrument. In conclusion, open-ended learning tasks like the writing of learning protocols can be made more effective by adaptive support based on prior strategy assessment.