feat: add mcp auth (#210)

feat: add auth

This commit adds support for OAuth authn/z flows at the MCP protocol
level.

Co-authored-by: Samuel Collard <[email protected]>
Co-authored-by: Dale Seo <[email protected]>

Author: 3 people

.changesets/feat_nc_authnz.md

@@ -0,0 +1,38 @@
+### feat: add mcp auth - @nicholascioli PR #210
+
+The MCP server can now be configured to act as an OAuth 2.1 resource server, following
+guidelines from the official MCP specification on Authorization / Authentication (see
+[the spec](https://modelcontextprotocol.io/specification/2025-06-18/basic/authorization)).
+
+To configure this new feature, a new `auth` section has been added to the SSE and
+Streamable HTTP transports. Below is an example configuration using Streamable HTTP:
+
+```yaml
+transport:
+  type: streamable_http
+  auth:
+    # List of upstream delegated OAuth servers
+    # Note: These need to support the OIDC metadata discovery endpoint
+    servers:
+    - https://auth.example.com
+
+    # List of accepted audiences from upstream signed JWTs
+    # See: https://www.ory.sh/docs/hydra/guides/audiences
+    audiences:
+    - mcp.example.audience
+
+    # The externally available URL pointing to this MCP server. Can be `localhost`
+    # when testing locally.
+    # Note: Subpaths must be preserved here as well. So append `/mcp` if using
+    # Streamable HTTP or `/sse` is using SSE.
+    resource: https://hosted.mcp.server/mcp
+
+    # Optional link to more documentation relating to this MCP server.
+    resource_documentation: https://info.mcp.server
+
+    # List of queryable OAuth scopes from the upstream OAuth servers
+    scopes:
+    - read
+    - mcp
+    - profile
+```

Cargo.lock

@@ -13,11 +13,16 @@ apollo-federation.workspace = true
 apollo-mcp-registry = { path = "../apollo-mcp-registry" }
 apollo-schema-index = { path = "../apollo-schema-index" }
 axum = "0.8.4"
+axum-extra = { version = "0.10.1", features = ["typed-header"] }
 bon = "3.6.3"
 clap = { version = "4.5.36", features = ["derive", "env"] }
 figment = { version = "0.10.19", features = ["env", "yaml"] }
 futures.workspace = true
+headers = "0.4.1"
+http = "1.3.1"
 humantime-serde = "1.1.1"
+jsonwebtoken = "9"
+jwks = "0.4.0"
 lz-str = "0.2.1"
 regex = "1.11.1"
 reqwest.workspace = true
@@ -35,9 +40,11 @@ tokio.workspace = true
 tracing.workspace = true
 tracing-subscriber = { version = "0.3.19", features = ["env-filter"] }
 tokio-util = "0.7.15"
+tower-http = { version = "0.6.6", features = ["cors"] }
 url.workspace = true
 
 [dev-dependencies]
+chrono = { version = "0.4.41", default-features = false, features = ["now"] }
 figment = { version = "0.10.19", features = ["test"] }
 insta.workspace = true
 rstest.workspace = true