#601

Global Rank · of 601 Skills

openapi-to-typescript AI Agent Skill

View Source: cachemoney/agent-toolkit

Safe

Installation

npx skills add cachemoney/agent-toolkit --skill openapi-to-typescript

6

Installs

OpenAPI to TypeScript

Converts OpenAPI 3.0 specifications to TypeScript interfaces and type guards.

Input: OpenAPI file (JSON or YAML)
Output: TypeScript file with interfaces and type guards

When to Use

  • "generate types from openapi"
  • "convert openapi to typescript"
  • "create API interfaces"
  • "generate types from spec"

Workflow

  1. Request the OpenAPI file path (if not provided)
  2. Read and validate the file (must be OpenAPI 3.0.x)
  3. Extract schemas from components/schemas
  4. Extract endpoints from paths (request/response types)
  5. Generate TypeScript (interfaces + type guards)
  6. Ask where to save (default: types/api.ts in current directory)
  7. Write the file

OpenAPI Validation

Check before processing:

- Field "openapi" must exist and start with "3.0"
- Field "paths" must exist
- Field "components.schemas" must exist (if there are types)

If invalid, report the error and stop.

Type Mapping

Primitives

OpenAPI TypeScript
string string
number number
integer number
boolean boolean
null null

Format Modifiers

Format TypeScript
uuid string (comment UUID)
date string (comment date)
date-time string (comment ISO)
email string (comment email)
uri string (comment URI)

Complex Types

Object:

// OpenAPI: type: object, properties: {id, name}, required: [id]
interface Example {
  id: string;      // required: no ?
  name?: string;   // optional: with ?
}

Array:

// OpenAPI: type: array, items: {type: string}
type Names = string[];

Enum:

// OpenAPI: type: string, enum: [active, draft]
type Status = "active" | "draft";

oneOf (Union):

// OpenAPI: oneOf: [{$ref: Cat}, {$ref: Dog}]
type Pet = Cat | Dog;

allOf (Intersection/Extends):

// OpenAPI: allOf: [{$ref: Base}, {type: object, properties: ...}]
interface Extended extends Base {
  extraField: string;
}

Code Generation

File Header

/**
 * Auto-generated from: {source_file}
 * Generated at: {timestamp}
 *
 * DO NOT EDIT MANUALLY - Regenerate from OpenAPI schema
 */

Interfaces (from components/schemas)

For each schema in components/schemas:

export interface Product {
  /** Product unique identifier */
  id: string;

  /** Product title */
  title: string;

  /** Product price */
  price: number;

  /** Created timestamp */
  created_at?: string;
}
  • Use OpenAPI description as JSDoc
  • Fields in required[] have no ?
  • Fields outside required[] have ?

Request/Response Types (from paths)

For each endpoint in paths:

// GET /products - query params
export interface GetProductsRequest {
  page?: number;
  limit?: number;
}

// GET /products - response 200
export type GetProductsResponse = ProductList;

// POST /products - request body
export interface CreateProductRequest {
  title: string;
  price: number;
}

// POST /products - response 201
export type CreateProductResponse = Product;

Naming convention:

  • {Method}{Path}Request for params/body
  • {Method}{Path}Response for response

Type Guards

For each main interface, generate a type guard:

export function isProduct(value: unknown): value is Product {
  return (
    typeof value === 'object' &&
    value !== null &&
    'id' in value &&
    typeof (value as any).id === 'string' &&
    'title' in value &&
    typeof (value as any).title === 'string' &&
    'price' in value &&
    typeof (value as any).price === 'number'
  );
}

Type guard rules:

  • Check typeof value === 'object' && value !== null
  • For each required field: check 'field' in value
  • For primitive fields: check typeof
  • For arrays: check Array.isArray()
  • For enums: check .includes()

Error Type (always include)

export interface ApiError {
  status: number;
  error: string;
  detail?: string;
}

export function isApiError(value: unknown): value is ApiError {
  return (
    typeof value === 'object' &&
    value !== null &&
    'status' in value &&
    typeof (value as any).status === 'number' &&
    'error' in value &&
    typeof (value as any).error === 'string'
  );
}

$ref Resolution

When encountering {"$ref": "#/components/schemas/Product"}:

  1. Extract the schema name (Product)
  2. Use the type directly (don't resolve inline)
// OpenAPI: items: {$ref: "#/components/schemas/Product"}
// TypeScript:
items: Product[]  // reference, not inline

Complete Example

Input (OpenAPI):

{
  "openapi": "3.0.0",
  "components": {
    "schemas": {
      "User": {
        "type": "object",
        "properties": {
          "id": {"type": "string", "format": "uuid"},
          "email": {"type": "string", "format": "email"},
          "role": {"type": "string", "enum": ["admin", "user"]}
        },
        "required": ["id", "email", "role"]
      }
    }
  },
  "paths": {
    "/users/{id}": {
      "get": {
        "parameters": [{"name": "id", "in": "path", "required": true}],
        "responses": {
          "200": {
            "content": {
              "application/json": {
                "schema": {"$ref": "#/components/schemas/User"}
              }
            }
          }
        }
      }
    }
  }
}

Output (TypeScript):

/**
 * Auto-generated from: api.openapi.json
 * Generated at: 2025-01-15T10:30:00Z
 *
 * DO NOT EDIT MANUALLY - Regenerate from OpenAPI schema
 */

// ============================================================================
// Types
// ============================================================================

export type UserRole = "admin" | "user";

export interface User {
  /** UUID */
  id: string;

  /** Email */
  email: string;

  role: UserRole;
}

// ============================================================================
// Request/Response Types
// ============================================================================

export interface GetUserByIdRequest {
  id: string;
}

export type GetUserByIdResponse = User;

// ============================================================================
// Type Guards
// ============================================================================

export function isUser(value: unknown): value is User {
  return (
    typeof value === 'object' &&
    value !== null &&
    'id' in value &&
    typeof (value as any).id === 'string' &&
    'email' in value &&
    typeof (value as any).email === 'string' &&
    'role' in value &&
    ['admin', 'user'].includes((value as any).role)
  );
}

// ============================================================================
// Error Types
// ============================================================================

export interface ApiError {
  status: number;
  error: string;
  detail?: string;
}

export function isApiError(value: unknown): value is ApiError {
  return (
    typeof value === 'object' &&
    value !== null &&
    'status' in value &&
    typeof (value as any).status === 'number' &&
    'error' in value &&
    typeof (value as any).error === 'string'
  );
}

Common Errors

Error Action
OpenAPI version != 3.0.x Report that only 3.0 is supported
$ref not found List missing refs
Unknown type Use unknown and warn
Circular reference Use type alias with lazy reference

Installs

Installs 6
Global Rank #601 of 601

Security Audit

ath Safe
socket Safe
Alerts: 0 Score: 90
snyk Low

How to use this skill

1

Install openapi-to-typescript by running npx skills add cachemoney/agent-toolkit --skill openapi-to-typescript in your project directory. Run the install command above in your project directory. The skill file will be downloaded from GitHub and placed in your project.

2

No configuration needed. Your AI agent (Claude Code, Cursor, Windsurf, etc.) automatically detects installed skills and uses them as context when generating code.

3

The skill enhances your agent's understanding of openapi-to-typescript, helping it follow established patterns, avoid common mistakes, and produce production-ready output.

What you get

Skills are plain-text instruction files — not executable code. They encode expert knowledge about frameworks, languages, or tools that your AI agent reads to improve its output. This means zero runtime overhead, no dependency conflicts, and full transparency: you can read and review every instruction before installing.

Compatibility

This skill works with any AI coding agent that supports the skills.sh format, including Claude Code (Anthropic), Cursor, Windsurf, Cline, Aider, and other tools that read project-level context files. Skills are framework-agnostic at the transport level — the content inside determines which language or framework it applies to.

Data sourced from the skills.sh registry and GitHub. Install counts and security audits are updated regularly.

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