# `ExMCP.Authorization.AuthorizationServerMetadata`
[🔗](https://github.com/azmaveth/ex_mcp/blob/v1.0.0/lib/ex_mcp/authorization/authorization_server_metadata.ex#L1)

OAuth 2.1 Authorization Server Metadata Discovery (RFC 8414).

This module implements the authorization server metadata discovery mechanism
as specified in RFC 8414. It provides the /.well-known/oauth-authorization-server
endpoint that returns authorization server capabilities and configuration.

## Example

    # Generate metadata from application configuration
    metadata = AuthorizationServerMetadata.build_metadata()

    # Metadata includes required fields like issuer, endpoints, and capabilities
    %{
      "issuer" => "https://auth.example.com",
      "authorization_endpoint" => "https://auth.example.com/authorize",
      "token_endpoint" => "https://auth.example.com/token",
      "scopes_supported" => ["mcp:read", "mcp:write"],
      "response_types_supported" => ["code"],
      "grant_types_supported" => ["authorization_code"]
    }

# `metadata`

```elixir
@type metadata() :: %{required(String.t()) => term()}
```

# `build_metadata`

```elixir
@spec build_metadata() :: metadata()
```

Builds the authorization server metadata from application configuration.

Returns a map containing the authorization server metadata as specified
in RFC 8414. The metadata includes both required and optional fields
based on the application's OAuth configuration.

## Required Fields (RFC 8414)
- `issuer`: The authorization server issuer identifier
- `authorization_endpoint`: URL of the authorization endpoint
- `token_endpoint`: URL of the token endpoint

## Optional Fields
- `jwks_uri`: URL of the JWK Set document
- `scopes_supported`: List of supported OAuth 2.0 scopes
- `response_types_supported`: List of supported response types
- `grant_types_supported`: List of supported grant types
- `code_challenge_methods_supported`: List of supported PKCE methods
- `introspection_endpoint`: URL of the token introspection endpoint
- `revocation_endpoint`: URL of the token revocation endpoint

## Examples

    iex> AuthorizationServerMetadata.build_metadata()
    %{
      "issuer" => "https://auth.example.com",
      "authorization_endpoint" => "https://auth.example.com/authorize",
      "token_endpoint" => "https://auth.example.com/token",
      "scopes_supported" => ["mcp:read", "mcp:write"],
      "response_types_supported" => ["code"],
      "grant_types_supported" => ["authorization_code"]
    }

# `validate_config`

```elixir
@spec validate_config() :: :ok | {:error, term()}
```

Validates that the authorization server metadata configuration is complete.

Checks that all required fields are present in the application configuration
and returns :ok if valid, or {:error, reason} if configuration is missing
or invalid.

## Examples

    iex> AuthorizationServerMetadata.validate_config()
    :ok

    iex> AuthorizationServerMetadata.validate_config()
    {:error, {:missing_required_field, :issuer}}

---

*Consult [api-reference.md](api-reference.md) for complete listing*