0افehknqtwz░◈Ξ∞xcلgjmpsvy▒◇∆π1بdفilorux▓◆∇∑0افehknqtwz░◈Ξ∞xcلgjmpsvy▒◇∆π1بdفilor

dفilorux▓◆∇∑0افehknqtwz░◈Ξ∞xcلgjmpsvy▒◇∆π1بdفilorux▓◆∇∑0افehknqtwz░◈Ξ∞xcلgjmpsvy

jmpsvy▒◇∆π1بdفilorux▓◆∇∑0افehknqtwz░◈Ξ∞xcلgjmpsvy▒◇∆π1بdفilorux▓◆∇∑0افehknqtwz░◈

qtwz░◈Ξ∞xcلgjmpsvy▒◇∆π1بdفilorux▓◆∇∑0افehknqtwz░◈Ξ∞xcلgjmpsvy▒◇∆π1بdفilorux▓◆∇∑0

x▓◆∇∑0افehknqtwz░◈Ξ∞xcلgjmpsvy▒◇∆π1بdفilorux▓◆∇∑0افehknqtwz░◈Ξ∞xcلgjmpsvy▒◇∆π1بd

◇∆π1بdفilorux▓◆∇∑0افehknqtwz░◈Ξ∞xcلgjmpsvy▒◇∆π1بdفilorux▓◆∇∑0افehknqtwz░◈Ξ∞xcلgj

∞xcلgjmpsvy▒◇∆π1بdفilorux▓◆∇∑0افehknqtwz░◈Ξ∞xcلgjmpsvy▒◇∆π1بdفilorux▓◆∇∑0افehknq

فehknqtwz░◈Ξ∞xcلgjmpsvy▒◇∆π1بdفilorux▓◆∇∑0افehknqtwz░◈Ξ∞xcلgjmpsvy▒◇∆π1بdفilorux

ilorux▓◆∇∑0افehknqtwz░◈Ξ∞xcلgjmpsvy▒◇∆π1بdفilorux▓◆∇∑0افehknqtwz░◈Ξ∞xcلgjmpsvy▒◇

psvy▒◇∆π1بdفilorux▓◆∇∑0افehknqtwz░◈Ξ∞xcلgjmpsvy▒◇∆π1بdفilorux▓◆∇∑0افehknqtwz░◈Ξ∞

wz░◈Ξ∞xcلgjmpsvy▒◇∆π1بdفilorux▓◆∇∑0افehknqtwz░◈Ξ∞xcلgjmpsvy▒◇∆π1بdفilorux▓◆∇∑0اف

◆∇∑0افehknqtwz░◈Ξ∞xcلgjmpsvy▒◇∆π1بdفilorux▓◆∇∑0افehknqtwz░◈Ξ∞xcلgjmpsvy▒◇∆π1بdفi

π1بdفilorux▓◆∇∑0افehknqtwz░◈Ξ∞xcلgjmpsvy▒◇∆π1بdفilorux▓◆∇∑0افehknqtwz░◈Ξ∞xcلgjmp

cلgjmpsvy▒◇∆π1بdفilorux▓◆∇∑0افehknqtwz░◈Ξ∞xcلgjmpsvy▒◇∆π1بdفilorux▓◆∇∑0افehknqtw

hknqtwz░◈Ξ∞xcلgjmpsvy▒◇∆π1بdفilorux▓◆∇∑0افehknqtwz░◈Ξ∞xcلgjmpsvy▒◇∆π1بdفilorux▓◆

orux▓◆∇∑0افehknqtwz░◈Ξ∞xcلgjmpsvy▒◇∆π1بdفilorux▓◆∇∑0افehknqtwz░◈Ξ∞xcلgjmpsvy▒◇∆π

vy▒◇∆π1بdفilorux▓◆∇∑0افehknqtwz░◈Ξ∞xcلgjmpsvy▒◇∆π1بdفilorux▓◆∇∑0افehknqtwz░◈Ξ∞xc

░◈Ξ∞xcلgjmpsvy▒◇∆π1بdفilorux▓◆∇∑0افehknqtwz░◈Ξ∞xcلgjmpsvy▒◇∆π1بdفilorux▓◆∇∑0افeh

∑0افehknqtwz░◈Ξ∞xcلgjmpsvy▒◇∆π1بdفilorux▓◆∇∑0افehknqtwz░◈Ξ∞xcلgjmpsvy▒◇∆π1بdفilo

بdفilorux▓◆∇∑0افehknqtwz░◈Ξ∞xcلgjmpsvy▒◇∆π1بdفilorux▓◆∇∑0افehknqtwz░◈Ξ∞xcلgjmpsv

gjmpsvy▒◇∆π1بdفilorux▓◆∇∑0افehknqtwz░◈Ξ∞xcلgjmpsvy▒◇∆π1بdفilorux▓◆∇∑0افehknqtwz░

nqtwz░◈Ξ∞xcلgjmpsvy▒◇∆π1بdفilorux▓◆∇∑0افehknqtwz░◈Ξ∞xcلgjmpsvy▒◇∆π1بdفilorux▓◆∇∑

ux▓◆∇∑0افehknqtwz░◈Ξ∞xcلgjmpsvy▒◇∆π1بdفilorux▓◆∇∑0افehknqtwz░◈Ξ∞xcلgjmpsvy▒◇∆π1ب

▒◇∆π1بdفilorux▓◆∇∑0افehknqtwz░◈Ξ∞xcلgjmpsvy▒◇∆π1بdفilorux▓◆∇∑0افehknqtwz░◈Ξ∞xcلg

rehan@neural-mesh :~

$ ▊

rehan.osRehan Rao

AI · Prompts 2025 · 04 6 min

Prompt engineering isn't clever — it's contract design.

The best prompts read like function signatures. Types, constraints, error paths. Cleverness is fragility.

Rehan Rao

AI & Backend Systems Engineer

architectureprompt.contract

The prompts that survive contact with production do not read like poetry. They read like typed function signatures with pre- and post-conditions. Cleverness is a liability because it hides intent from the next engineer — and from the model.

The principle

A prompt is a contract between your system and a stochastic function. The contract has an input schema, an output schema, and a set of error paths. Anything else is decoration.

The contract shape

SYSTEM:
You are a citation extractor.

INPUT (JSON):
  { "doc": string, "max_citations": int }

OUTPUT (JSON, strict):
  { "citations": [{ "quote": string, "page": int }],
    "confidence": number,
    "error": null | "no_source" | "ambiguous" }

RULES:
- Never invent quotes not present verbatim in "doc".
- If unsure, set error and return [].

Error paths

Give the model a way to say “I don't know.” A prompt without an error slot forces hallucination — the model has no legal way to abstain.

caveat

Every prompt in production should have an error field in its output schema. Downstream code that treats abstention as a valid response is dramatically more reliable than one that assumes success.

Testing prompts

Snapshot tests on the JSON schema — any drift fails CI.
A small golden set of 20-50 cases, graded deterministically.
Adversarial cases: empty doc, contradictory doc, prompt-injection doc.

Ship the prompt like you ship any other function: typed, tested, versioned, monitored.