skills / davila7 / claude-code-templates / openapi-to-typescript 
openapi-to-typescript 
$ npx skills add https://github.com/davila7/claude-code-templates --skill openapi-to-typescript SKILL.md 
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 
Request the OpenAPI file path (if not provided) 
Read and validate the file (must be OpenAPI 3.0.x) 
Extract schemas from 
components/schemas 
Extract endpoints from 
paths (request/response types) 
Generate TypeScript (interfaces + type guards) 
Ask where to save (default: 
types/api.ts in current directory) 
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"} : 
Extract the schema name ( 
Product ) 
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 Weekly Installs 79 Repository davila7/claude-code-templates First Seen Jan 25, 2026 Security Audits Gen Agent Trust Hub Pass Socket Pass Snyk Pass Installed on claude-code 63 opencode 55 cursor 53 antigravity 52 gemini-cli 50 codex 40