Under the Hood: Prompt tuning Shake to Summarize for recipes

Firefox’s Shake to Summarize feature, available on iOS and Android since May, uses a smaller language model to create concise summaries of web content. Mozilla explains the prompt engineering process behind the feature, focusing on how specificity improves output quality for smaller models. The company notes that smaller models require clearer instructions than larger ones, as they lack the ability to infer unstated intentions.

The team discovered that summary expectations vary by content type. For recipes, summaries must retain exact ingredient amounts and steps, while novel summaries can omit verbatim text. This led Mozilla to develop separate instructions for each content category, ensuring summaries meet user needs for different use cases.

Mozilla collaborated with the product team to define summary requirements for each article type. Recipes required ingredients, steps, time, and tips; news needed key details like events and consequences; how-to guides listed materials, steps, and warnings; reviews included ratings, pros, cons, price, and audience; research highlighted findings, confidence, and impact.

After testing the initial prompt, Mozilla found it worked well for most content but struggled with recipes, often omitting key ingredients or the entire recipe. A revised prompt explicitly instructed the model to include essential recipe details while discarding less critical narrative elements, improving usability for mobile users.