Clear instructions matter, but production quality depends on the full system around a model: context, tools, evaluation, safety and user feedback.
Treat prompts as product logic
Version important instructions, define the intended audience and output format, and keep business rules separate from untrusted user content.
Create representative test sets
Collect normal, difficult and adversarial examples. Score factuality, relevance, tone and task completion using criteria that reflect the real user journey.
Design for graceful failure
Let the system ask for missing information, cite approved sources and hand off when confidence is low. A trustworthy refusal is better than a fluent invention.
Further learning
Use these primary resources to continue learning: