Prompt Engineering Foundations
Where an instruction belongs — tool description, system prompt, or user turn — why emphasis that worked on older models now causes over-triggering, and the prompt patterns that have expired.
Last updated
After this section you can
- Place an instruction in the right surface — tool description, system prompt, or user turn — and say what breaks when it is in the wrong one
- Strip emphasis that made older models comply and now causes over-triggering
- Recognise the prompt patterns that expired, and name the API feature that replaced each
Prompt Engineering Foundations
Where an instruction lives decides whether it is followed, cached, or quietly ignored. And the current models follow the system prompt closely enough that prompts written to overcome older ones now overshoot.
Most prompt problems are not wording problems — they are placement problems. A prompt is three surfaces rendered in a fixed order (tools, then system, then messages), and each has a different lifetime, a different cost, and a different moment at which the model reads it. Put an instruction in the wrong surface and it either gets ignored at the moment it mattered or destroys your prompt cache. The second half of the job is volume: emphasis was a workaround for models that under-followed instructions, and on current models the same emphasis causes over-triggering.