Article V: prompt schema standards

The law of syntax

Prompts are not emails to a helpful assistant. They are compiled programs that execute on probabilistic hardware. They deserve the same rigor as application code.

Section 1: zero-tolerance for prose formatting

Natural language format requests (“Please format this as a JSON object with the following fields…”) are illegal. All formatting must be enforced via JSON Schema, XML, or strict function signatures.

Prohibited:

Please respond with a JSON object containing "title" and "summary" fields.

Required:

{
  "response_format": {
    "type": "json_schema",
    "json_schema": { ... }
  }
}

Prose formatting instructions waste tokens, fail unpredictably, and cannot be validated in CI. Schema-enforced outputs can.

Section 2: the scaffolding ban

System prompts cannot contain development notes, redundant instructions, or “politeness tokens.”

Audit your system prompts for constitutional violations:

• "You are a helpful assistant": politeness tax, delete it
• "Take a deep breath and think step by step": unmeasurable, delete it
• // TODO: update this when we switch models: development debris, delete it
• Repeated instructions already enforced by schema: redundant, delete it

Every token in a system prompt is a token paid on every request. System prompts are not draft documents. They are production configuration.

Section 3: CI/CD token regression

Any pull request that increases the token footprint of a core prompt template by more than 5% must trigger a manual cost-review blocker.

Prompt changes are code changes. They require:

• Token counting in CI: measure input token count of every prompt template on every PR
• Regression thresholds: >5% increase blocks merge without FinOps sign-off
• Cost projection: estimate monthly cost impact based on current request volume
• Version history: prompt templates are versioned artifacts, not string literals scattered across files

A prompt that grows 200 tokens does not sound expensive. At 10 million requests per month, it is a line item.

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Practice: Prompt hygiene