aether-auth

OAuth credential storage and authorization flows for Aether. Provides a pluggable credential storage trait, an OS-keychain-backed implementation, and an end-to-end OAuth authorization-code flow for MCP servers.

Table of Contents

• Key Types
• Usage
• Feature Flags
• License

Key Types

• OAuthCredentialStorage -- Trait for persisting OAuth credentials keyed by provider ID, MCP server ID, or another credential key.
• OAuthCredential -- Access token, refresh token, client ID, and expiry timestamp for a single OAuth identity.
• OAuthHandler -- Trait implemented by consuming applications to drive the OAuth UI/UX (open a browser, wait for the redirect).
• BrowserOAuthHandler -- Default OAuthHandler that opens the system browser and listens on a dynamic local port.
• OsKeyringStore -- OAuthCredentialStorage backed by the OS keychain (macOS Keychain, Windows Credential Manager, Linux/FreeBSD Secret Service). Available under the keyring feature.
• FakeOAuthCredentialStore -- In-memory OAuthCredentialStorage for tests.
• McpCredentialStore -- Per-server adapter that binds an OAuthCredentialStorage to one MCP server ID and implements rmcp::transport::auth::CredentialStore. Available under the mcp feature.
• OAuthError -- Error enum returned by every fallible API in this crate.

Usage

Implement OAuthCredentialStorage for your own backend, or use the OS keychain store under the keyring feature:

use aether_auth::{OAuthCredential, OAuthCredentialStorage, OsKeyringStore};

# async fn example() -> Result<(), aether_auth::OAuthError> {
let store = OsKeyringStore::with_platform_store();

store
    .save_credential(
        "anthropic",
        OAuthCredential {
            client_id: "client-id".into(),
            access_token: "token".into(),
            refresh_token: None,
            expires_at: None,
        },
    )
    .await?;

let loaded = store.load_credential("anthropic").await?;
# Ok(())
# }

For MCP servers that require OAuth, the mcp feature integrates Aether's browser and callback UI with rmcp's authorization state machine.

Feature Flags

License

MIT