Inferensys

Prompt

Request/Response Schema Documentation Prompt Template

A practical prompt playbook for generating accurate, human-readable field tables and nested object descriptions from JSON Schema or OpenAPI schema objects, with built-in validation against schema drift and missing enum documentation.
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PROMPT PLAYBOOK

When to Use This Prompt

Understand the ideal job-to-be-done, required inputs, and clear boundaries for the schema documentation prompt.

This prompt is designed for a specific, high-value task: converting a raw JSON Schema or OpenAPI schema object into polished, developer-facing reference documentation. The ideal user is an API designer, documentation engineer, or platform team member who already has a valid, machine-readable schema and needs to generate the human-readable field-level tables that form the core of an API reference. The prompt's job is not to interpret an API's behavior or to write endpoint descriptions; it is strictly to translate structural schema definitions—types, constraints, defaults, nullability, and nested object shapes—into clear, consistent prose and markdown tables that can be embedded directly into a developer portal or SDK documentation.

You should use this prompt when your primary goal is to keep your reference documentation synchronized with a live API contract. It excels in environments where the schema is the source of truth, such as a CI/CD pipeline that lints an OpenAPI spec and then automatically regenerates documentation. The prompt assumes you are providing a complete and valid schema object as input. It will produce the best results when you also supply context like a [STYLE_GUIDE] for tone and formatting, and an [OUTPUT_SCHEMA] to strictly control the structure of the generated markdown. Do not use this prompt to generate a schema from code, to document the behavior of specific HTTP endpoints (methods, headers, auth), or to write high-level conceptual guides. It is a precision tool for a single, repeatable documentation generation step.

Before using this prompt, ensure your input schema is valid and complete. A common failure mode is providing a partial schema, which will result in documentation with missing fields or constraints. Another is schema drift, where the schema object no longer matches the live API. To mitigate this, the prompt's output should always be validated against the original schema in your implementation harness. The next step after reading this section is to prepare your schema input and review the prompt template to understand its required placeholders. Avoid the temptation to use this prompt for generating example values or endpoint-level documentation; those are separate, specialized tasks covered by other playbooks in this pillar.

PRACTICAL GUARDRAILS

Use Case Fit

This prompt template is designed for generating human-readable schema documentation from machine-readable sources like JSON Schema or OpenAPI objects. It excels at structured, repetitive documentation tasks but requires strict input contracts and validation to prevent drift.

01

Strong Fit: Schema-First API Development

Use when: You have a complete, validated JSON Schema or OpenAPI specification and need to generate consistent field tables, type definitions, and constraint documentation. Guardrail: Always validate the input schema before prompting to prevent garbage-in, garbage-out documentation.

02

Poor Fit: Undocumented Legacy APIs

Avoid when: The source of truth is only the running code with no formal schema. The model will hallucinate types and constraints. Guardrail: Use a code-analysis or traffic-capture tool to generate an OpenAPI spec first, then use this prompt on the generated spec.

03

Required Input: A Strict Schema Object

Risk: Providing a partial or invalid schema will produce incomplete or incorrect documentation. Guardrail: The prompt harness must include a JSON Schema or OpenAPI validator that rejects malformed input before the LLM call is made.

04

Operational Risk: Schema Drift

Risk: The API implementation changes but the documentation prompt is not re-run, causing the docs to become stale. Guardrail: Integrate this prompt into a CI/CD pipeline that triggers on schema file changes and fails the build if the generated docs don't match the new spec.

05

Operational Risk: Missing Enum Value Documentation

Risk: The model lists enum values but fails to explain what each value means, leaving the documentation technically accurate but practically useless. Guardrail: The prompt must explicitly instruct the model to generate a description for every enum value, and the eval harness must check for this.

06

Poor Fit: Highly Nuanced or Legal Context

Risk: The model may oversimplify complex business logic or regulatory constraints described in a schema's description field. Guardrail: Treat the generated output as a first draft. A human reviewer must verify that all business-critical constraints and legal implications are accurately and completely documented.

PROMPT PLAYBOOK

Copy-Ready Prompt Template

A reusable prompt template that converts JSON Schema or OpenAPI schema objects into human-readable field documentation tables.

This prompt template transforms raw schema objects into structured, developer-facing documentation. It accepts a JSON Schema or OpenAPI schema fragment as input and produces field-level documentation including types, constraints, defaults, nullability, and nested object descriptions. The template is designed to be dropped directly into your AI harness—replace the square-bracket placeholders with your actual schema objects, output format requirements, and any domain-specific constraints before execution.

code
You are an API documentation specialist. Your task is to convert a JSON Schema or OpenAPI schema object into a human-readable field documentation table.

## INPUT SCHEMA
[SCHEMA_OBJECT]

## OUTPUT FORMAT
[OUTPUT_SCHEMA]

## CONSTRAINTS
- Document every field present in the schema, including nested properties.
- For each field, include: field name, data type, required/optional status, default value (if specified), nullability, format constraints (min/max, pattern, enum values), and a human-readable description.
- If the schema includes `oneOf`, `anyOf`, or `allOf`, document each variant clearly and note the discriminator field if present.
- Flag any fields where the description is missing, ambiguous, or appears to be a placeholder.
- If enum values are present, list every accepted value. Flag any enum without descriptions.
- Preserve any `deprecated` annotations and include a deprecation warning in the field description.
- For nested objects, produce a separate sub-table or indented section that maintains parent-child relationships.
- Do not invent field descriptions. If no description exists in the schema, mark the field as `[DESCRIPTION MISSING]`.
- Do not alter types, constraints, or enum values from the source schema.

## EXAMPLES
[EXAMPLES]

## ADDITIONAL CONTEXT
[CONTEXT]

## RISK LEVEL
[RISK_LEVEL]

Generate the field documentation table now.

To adapt this template, replace [SCHEMA_OBJECT] with the raw JSON Schema or OpenAPI schema fragment you need documented. Set [OUTPUT_SCHEMA] to your desired output structure—typically a markdown table with columns for field name, type, required, default, nullable, constraints, and description. Use [EXAMPLES] to provide one or two correctly documented fields that demonstrate your team's preferred style and level of detail. The [CONTEXT] placeholder accepts any additional domain knowledge, such as authentication requirements, pagination conventions, or error handling patterns that should inform the descriptions. Set [RISK_LEVEL] to low, medium, or high to control validation strictness—high-risk contexts should trigger mandatory human review of all [DESCRIPTION MISSING] flags and enum documentation gaps before publication. After generating the documentation, always validate the output against the source schema to catch type mismatches, missing fields, or invented descriptions before the content reaches your developer portal.

IMPLEMENTATION TABLE

Prompt Variables

Required and optional inputs for the Request/Response Schema Documentation prompt. Validate each before calling the model to prevent hallucinated field descriptions or schema drift.

PlaceholderPurposeExampleValidation Notes

[SCHEMA_SOURCE]

Raw JSON Schema or OpenAPI schema object to document

{"type":"object","properties":{"id":{"type":"string","format":"uuid"}},"required":["id"]}

Must parse as valid JSON Schema draft-07 or later. Reject if schema fails JSON.parse or contains circular $ref not resolved.

[SCHEMA_TYPE]

Classification of the schema: request, response, webhook payload, or error body

response

Must be one of: request, response, webhook_payload, error_body. Controls which documentation template is applied.

[ENDPOINT_CONTEXT]

HTTP method, path, and operation summary for context

POST /v1/payments

Must include method and path. Used to generate example cURL and contextualize field descriptions.

[AUTH_SCOPE]

Required OAuth scope or API key permission for this endpoint

payments:write

Optional. If provided, auth requirement is documented in the output. If null, auth section is omitted.

[NESTING_DEPTH]

Maximum depth for documenting nested objects before linking to child schemas

3

Integer 1-5. Default 3. Prevents recursive schema explosion. Deeper objects get a $ref link instead of inline expansion.

[ENUM_EXPANSION]

Whether to list all enum values inline or link to a separate enum reference

Boolean. true lists values in the field table. false generates a reference link. Required when schema contains enum fields.

[EXAMPLE_STRATEGY]

How to generate example values: from schema examples, generate realistic, or omit

from_schema

Must be one of: from_schema, generate, omit. generate requires a separate validation pass to confirm examples match schema constraints.

[OUTPUT_FORMAT]

Target documentation format: markdown table, HTML, or OpenAPI description field

markdown

Must be one of: markdown, html, openapi_description. Controls output structure and escaping rules.

PROMPT PLAYBOOK

Implementation Harness Notes

How to wire the schema documentation prompt into a reliable, testable application pipeline.

Integrating the Request/Response Schema Documentation prompt into a production workflow requires treating it as a deterministic documentation generator with strict validation gates, not a one-off chat interaction. The prompt expects a JSON Schema or OpenAPI schema object as its primary input and produces structured documentation including field tables, type constraints, nullability flags, and nested object descriptions. The harness must ensure that the input schema is valid before the prompt runs, that the output matches the expected documentation structure, and that any drift between the schema and the generated docs is caught before publication. This is a high-accuracy workflow where missing an enum value or misrepresenting a required field directly harms downstream API consumers.

Build the harness around a validate → generate → validate → repair loop. Before calling the model, validate the input schema against its specification (JSON Schema Draft 2020-12 or OpenAPI 3.x) using a standard parser. Feed the validated schema into the prompt along with any [OUTPUT_SCHEMA] that defines the expected documentation format. After generation, run structural validation on the output: confirm every field in the source schema appears in the documentation, every documented type matches the schema type, all required fields are marked as required, all enum values are listed, and nested objects are recursively documented. If validation fails, route the errors back into a repair prompt that includes the original schema, the failed output, and the specific validation failures. Limit repair attempts to 2 retries before flagging for human review. Log every generation attempt, validation result, and repair action for auditability.

For model selection, prefer models with strong JSON mode and structured output support (GPT-4o, Claude 3.5 Sonnet, or equivalent). Set response_format to json_object or use the model's native structured output feature with the documentation schema as the target. Implement a human approval gate for any schema that contains deprecated fields, breaking changes, or security-sensitive parameters (auth tokens, PII fields). The approval step should present a diff between the previous documentation version and the new generated version. Avoid wiring this prompt directly into a CI/CD pipeline without the validation and approval gates—schema documentation errors propagate to every API consumer and are expensive to correct after publication.

IMPLEMENTATION TABLE

Expected Output Contract

Define the exact fields, types, and validation rules the model must produce when generating schema documentation. Use this contract to build a parser, validator, or retry loop in your application harness.

Field or ElementType or FormatRequiredValidation Rule

schema_title

string

Must match the top-level title from the source schema or a human-readable derivative. Reject if empty or generic placeholder like 'Untitled'.

field_table

array of objects

Each object must contain name, type, required, description, and constraints keys. Reject if the array is empty when the source schema has properties.

field_table[].name

string

Must exactly match a property name in the source JSON Schema or OpenAPI schema object. Case-sensitive check required.

field_table[].type

string

Must be a valid JSON Schema type or custom format string. Reject if type is not in the allowed set: string, number, integer, boolean, array, object, null, or a defined format.

field_table[].required

boolean

Must be true if the field is in the source schema's required array, otherwise false. Boolean mismatch triggers a validation failure.

field_table[].description

string

Must be a non-empty string. Reject if null, empty, or a verbatim copy of the field name. Minimum 10 characters unless the field is self-evident.

field_table[].constraints

string or null

If present, must describe enum values, min/max, pattern, or format rules. Reject if it contradicts the source schema constraints. Null allowed for unconstrained fields.

nested_object_tables

array of objects

If the source schema has nested objects, a separate field table must be generated for each. Reject if a nested object is flattened into the parent table without a reference.

PRACTICAL GUARDRAILS

Common Failure Modes

Schema documentation prompts fail in predictable ways. These cards cover the most common failure modes when generating request/response schema documentation from JSON Schema or OpenAPI objects, along with concrete guardrails to prevent them.

01

Silent Enum Value Omission

What to watch: The model documents some enum values but skips others, especially when enum arrays are long or contain similar-looking variants. The output looks plausible but is incomplete. Guardrail: Post-process the output by extracting all documented enum values and diffing against the source schema's enum array. Flag any missing values and re-prompt with the specific missing entries listed explicitly.

02

Nullability and Required Field Confusion

What to watch: The model conflates nullable: true with required: false, or documents a field as optional when the schema marks it required but nullable. This causes integrators to mishandle null payloads. Guardrail: Include an explicit instruction in the prompt template: 'For each field, state whether it is required in the request, whether it can be null, and whether a missing key is treated differently from a null value.' Validate output against the schema's required array and nullable properties.

03

Nested Object Depth Collapse

What to watch: Deeply nested objects (3+ levels) get flattened or summarized as 'complex object' without documenting the full substructure. Downstream consumers lose visibility into inner field constraints. Guardrail: Add a constraint: 'Document all nested objects recursively to full depth. If a nested object exceeds 5 levels, document the first 5 levels and note the remaining depth.' Use a recursive schema walker in the harness to verify that every properties key in the source appears in the output.

04

Constraint and Validation Rule Drift

What to watch: Numeric constraints (minimum, maximum, multipleOf), string patterns (pattern, minLength, maxLength), and array limits (minItems, maxItems) are paraphrased inaccurately or omitted entirely. Guardrail: Require the prompt to output constraints in a structured format (e.g., a dedicated constraints column) rather than prose. Validate constraint values programmatically against the source schema after generation.

05

Polymorphic Schema Misrepresentation

What to watch: oneOf, anyOf, and allOf combinators are documented as if they are a single flat object, losing discriminator fields and variant-specific properties. Integrators cannot determine which variant applies. Guardrail: Add a dedicated section in the prompt template for polymorphic types: 'For any schema using oneOf, anyOf, or allOf, document each variant separately with its discriminator value and variant-specific fields. Include a decision table showing which variant applies under which conditions.'

06

Example Payload Schema Mismatch

What to watch: The model generates example request or response payloads that violate the schema they are supposed to illustrate—wrong types, missing required fields, or invented enum values. Guardrail: Run every generated example through a JSON Schema validator against the source schema. If validation fails, feed the validation errors back into a repair prompt. Include a note in the output: 'Example validated against schema v[X.Y].'

IMPLEMENTATION TABLE

Evaluation Rubric

Use this rubric to test the quality of generated schema documentation before shipping. Each criterion targets a specific failure mode common in request/response schema documentation prompts.

CriterionPass StandardFailure SignalTest Method

Schema Completeness

Every field in the source [JSON_SCHEMA] appears in the output documentation

Output omits a required field, optional field, or nested property present in the source schema

Parse source schema keys recursively; diff against documented field names

Type Accuracy

Documented type matches the source schema type for every field, including nullability

Type mismatch (e.g., string documented as integer) or nullability not indicated when type array includes null

Schema comparison script: for each field, assert documented_type == source_type

Constraint Documentation

All constraints (minLength, maxLength, minimum, maximum, pattern, enum, minItems, maxItems) are documented

Constraint present in source schema but absent from documentation row for that field

Extract constraints from source schema; verify each appears in the corresponding field description

Enum Value Completeness

Every enum value is listed exactly as defined in the source schema

Enum values truncated, reworded, or missing; placeholder text like 'various values' used instead

String match each enum member from source against documented enum list

Nested Object Handling

Nested objects and arrays of objects are documented with their own field tables or inline field descriptions

Nested object documented only as 'object' without sub-fields; array items type undocumented

Recursive walk of source schema; verify sub-schema documentation exists for every object and array item definition

Default Value Documentation

Default values from the source schema are documented when present

Default value omitted from documentation row when source schema includes a default keyword

For each field with a default in source, assert default value appears in documentation

Deprecation Flagging

Fields marked deprecated in source schema are flagged in documentation with deprecation notice

Deprecated field documented without any deprecation indicator or migration guidance

Check deprecated: true fields in source; verify documentation row contains deprecation language

Example Validity

Provided examples validate against the field schema they illustrate

Example value fails validation against source schema (wrong type, violates constraint, invalid enum)

Run each documented example through a JSON Schema validator against the corresponding field schema

ADAPTATION OPTIONS

Adapt This Prompt

How to adapt

Use the base prompt with a single schema object and lighter validation. Remove strict output format constraints and allow the model to describe fields in natural paragraphs before enforcing the field table structure. Start with a well-known schema like a User or Order object to calibrate output quality.

Watch for

  • Missing enum value documentation when enums are present
  • Overly verbose descriptions that bury type information
  • Nullable fields described as required
  • Nested object flattening without preserving parent-child relationships
Prasad Kumkar

About the author

Prasad Kumkar

CEO & MD, Inference Systems

Prasad Kumkar is the CEO & MD of Inference Systems and writes about AI systems architecture, LLM infrastructure, model serving, evaluation, and production deployment. Over 5+ years, he has worked across computer vision models, L5 autonomous vehicle systems, and LLM research, with a focus on taking complex AI ideas into real-world engineering systems.

His work and writing cover AI systems, large language models, AI agents, multimodal systems, autonomous systems, inference optimization, RAG, evaluation, and production AI engineering.