A prompt template is a reusable prompt for a recurring task. Its instructions, constraints, and output structure remain stable; input parameters supply changing facts at runtime. Filling the parameters produces a prompt for one case without redesigning the task. section 5.1
Design the stable and changing parts separately:
- Define the task and its boundaries with instructions and, where useful, a role. State constraints that the response must not violate. section 5.2.1
- Name parameters for facts that change between runs, such as {{feature_name}}, {{acceptance_criteria}}, and {{target_release}}. Delimit dense supplied context so it remains distinguishable from instructions. section 5.2.1 section 5.3.1
- Specify the required output sections and level of detail. The template pattern can enforce a fixed output shape, but it is only one pattern a prompt template may use. section 5.0 section 5.2.1
Feature implementation plan
A reusable plan prompt can assign a senior-engineer role, require use of only the supplied feature request, and forbid invented requirements. Its input block holds {{feature_name}}, {{business_goal}}, {{acceptance_criteria}}, {{constraints}}, and {{target_release}}. Its output format requires Scope, Implementation Steps, Risks, and a Delivery Checkpoint. Inject a different ticket to obtain a comparable plan without changing those instructions or headings. section 5.2.2 section 5.2.3
For higher-risk work, use templates as a multistep workflow rather than forcing an immediate answer. A legacy-refactor workflow first asks questions about hidden dependencies, migration risk, and rollback. A second template injects the assessment answers and requests a phased plan with a checkpoint. section 5.3 section 5.3.3
Test a template with varied input combinations before real-world use: check whether it follows the required format, respects constraints, and fails visibly when details are missing. Keep it specific enough for comparison without making it too rigid for varied cases. Store reusable templates in external template files rather than inline source code; production versioning and change control require separate attention. section 5.0 section 4.4.1 section 5.1 section 5.2.3
For repeated production use, keep stable behavior in a system prompt and changing, delimited data in a user prompt template. This avoids repeating instructions across requests. A simple one-off task may not need that separation. Do not confuse a reusable prompt template with the narrower template pattern: the latter controls output structure, while a prompt template can also coordinate inputs, constraints, and multiple steps. section 6.5 section 5.0
