rust-mcp-extra

rust-mcp-extra is a companion crate to rust-mcp-sdk providing additional implementations of core traits. It includes ready-made auth providers, ID generators, and more.

[dependencies]
rust-mcp-extra = "1.0"

Default features

The default feature set includes all ID generators and auth support.

ID Generators

Use these to customize how session IDs are generated. They implement the IdGenerator trait and plug into AxumServerOptions or ActixServerOptions:

use rust_mcp_extra::id_generator::SnowflakeIdGenerator;
use std::sync::Arc;

let server = rust_mcp_axum::create_axum_server(
    server_info, handler,
    AxumServerOptions {
        session_id_generator: Some(Arc::new(SnowflakeIdGenerator::new(1))), // machine ID = 1
        ..Default::default()
    },
);

Generator	Feature flag	Description
NanoIdGenerator	nano_id	Short, URL-safe random strings. Compact and user-friendly.
TimeBase64Generator	time_64_id	Timestamp (ms) encoded as URL-safe Base64. Time-sortable.
RandomBase62Generator	random_62_id	Alphanumeric [A-Za-z0-9] random strings.
SnowflakeIdGenerator	snowflake_id	64-bit time-ordered IDs with machine ID + sequence. Distributed-friendly.

Auth Providers

Drop-in providers for common identity platforms - no need to build an AuthProvider implementation yourself:

Provider	Module	Docs
Keycloak	auth_provider::keycloak	Keycloak
WorkOS AuthKit	auth_provider::work_os	WorkOS
Scalekit	auth_provider::scalekit	Scalekit

Each provider is a standalone AuthProvider implementation for MCP servers. They share the same building blocks from rust_mcp_sdk - AuthMetadataBuilder for discovery metadata and GenericOauthTokenVerifier for token verification - but none of them wraps RemoteAuthProvider, issues tokens, or performs registration. Token issuance and refresh always happen at the external identity provider; the providers here serve the OAuth discovery endpoints and verify incoming bearer tokens.

Token Verifiers

GenericOauthTokenVerifier implements the OauthTokenVerifier trait from rust-mcp-sdk. To customize how tokens are validated, compose VerificationStrategies (JWKs, introspection, UserInfo) inside TokenVerifierOptions - or implement OauthTokenVerifier yourself.

use rust_mcp_extra::token_verifier::{GenericOauthTokenVerifier, TokenVerifierOptions};

let verifier = GenericOauthTokenVerifier::new(TokenVerifierOptions {
    strategies: vec![/* JWKs / Introspection / UserInfo */],
    validate_audience: None,
    validate_issuer: None,
    cache_capacity: None,
})?;

See Token Verification for details.

Coming Soon

• Session Store - persistent session management (SQLite, Redis)
• Event Store - persistent event history for resumability

note

The sqlite module in rust-mcp-extra currently has placeholder implementations. These will be fleshed out in a future release.