Oliver 'Oli' Cheng
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Oli Cheng 1 min read Guide

Prompting Guide for Real Products (Not Prompt Theater)

How to write prompts as contracts: role, goals, constraints, and failure behavior that hold up in production.

  • Prompting
  • AI Engineering
  • Product
Prompting Guide for Real Products (Not Prompt Theater)

A lot of prompt advice sounds clever and performs terribly in production.

The core mistake: treating prompts as magic text instead of interface contracts.

Prompt quality is mostly specification quality

A strong production prompt usually makes these explicit:

  • role
  • objective
  • allowed actions
  • disallowed actions
  • output format
  • fallback behavior

If these are missing, your model is guessing your product intent.

The production prompt template I trust

SYSTEM:
You are {role} for {product context}.

GOAL:
Deliver {concrete outcome} for {user type}.

CONSTRAINTS:
- Do not invent facts, metrics, or citations.
- If required context is missing, ask exactly {N} clarifying questions.
- If confidence is low, return "uncertain" + reasons.

OUTPUT FORMAT:
Return markdown table with columns: {A, B, C}.
Keep response under {X} words.

QUALITY BAR:
- Specific
- Actionable
- Internally consistent

This is not pretty, but it is debuggable.

Prompt anti-patterns

  1. Overloaded system prompts Trying to embed your whole strategy doc in one prompt hurts clarity.

  2. No structural output requirements Free-form prose is hard to validate and diff.

  3. Hidden assumptions If assumptions are not surfaced, reviewers can’t challenge them.

  4. No graceful failure protocol You need a standard response shape for uncertainty.

Make prompt reviews part of engineering reviews

Treat prompt changes like logic changes.

My minimum checklist:

  • What behavior changed?
  • Which evals cover it?
  • What regressions are likely?
  • How do we roll back quickly?

Prompting and UX are one system

Prompt quality can’t compensate for bad UX scaffolding.

Give users:

  • structured inputs
  • clear examples
  • explicit expected output
  • confidence cues

The easiest way to improve prompts is often to improve the input surface.

The pragmatic conclusion

Stop chasing one perfect prompt. Build a prompt + eval + UX loop that improves every week.

That is how prompting becomes an advantage instead of a maintenance nightmare.