schema

Like serde, but for structure instead of serialization.

Turn Rust types into JSON schemas that describe their shape. Works with Claude AI tools, OpenAPI specs, or anything else that needs to understand your data structure.

#[derive(Schema)]
struct User { name: String, age: u32 }

User::schema() // → JSON schema describing the structure

Usage

use schema::Schema;

#[derive(Schema)]
struct User {
    name: String,
    age: u32,
    email: Option<String>,
}

let schema = User::schema();

Crates

• schema - Core derive macro
• schema-anthropic - Anthropic Claude tool schemas
• schema-openapi - OpenAPI 3.0 specs

Examples

Anthropic Tools

use schema::Schema;
use schema_anthropic::to_tool_schema;

#[derive(Schema)]
struct SearchFiles {
    /// Query to search for
    query: String,
    /// Maximum results to return
    limit: Option<u32>,
}

let tool = to_tool_schema::<SearchFiles>("search_files");
// Use with Claude API

OpenAPI Specs

use schema::Schema;
use schema_openapi::to_openapi_schema;

#[derive(Schema)]
struct CreateUser {
    username: String,
    email: String,
}

let spec = to_openapi_schema::<CreateUser>();
// Returns OpenAPI 3.0 schema object

Enums

#[derive(Schema)]
enum Status {
    Active,
    Inactive,
    Pending,
}

#[derive(Schema)]
enum Message {
    Text { content: String },
    Image { url: String, width: u32 },
}

Features

• Derives from Rust types
• Doc comments → descriptions
• Option<T> → optional fields
• Enums → string enums or tagged unions
• Nested structs supported
• #[schema(skip)] to skip fields

Installation

[dependencies]
schema = { git = "https://github.com/andrewgazelka/schema" }
schema-anthropic = { git = "https://github.com/andrewgazelka/schema" }
schema-openapi = { git = "https://github.com/andrewgazelka/schema" }

License

MIT