fix: oauth discovery not working with some clients (#666)01-12-fix_oauth_discovery_not_working_with_some_clients

### TL;DR

TESTING REMAINING. This is my hypothesis. @MaheshtheDev please carry on from here or we can test in prod.

Added a proxy endpoint for OAuth authorization server metadata to support non-compliant MCP clients.

### What changed?

Added a new endpoint `/.well-known/oauth-authorization-server` to the MCP server that proxies requests to the main API. This endpoint fetches the authorization server metadata from the API and returns it to clients.

### How to test?

1. Make a GET request to `/.well-known/oauth-authorization-server` on the MCP server
2. Verify that it returns the same metadata as the main API's `/.well-known/oauth-authorization-server` endpoint
3. Test with a client that expects to find the authorization server metadata on the MCP domain

### Why make this change?

Some MCP clients don't correctly follow the OAuth specification. Instead of using the `authorization_servers` array provided in the protected resource metadata, they look for the authorization server metadata directly on the MCP server domain. This proxy endpoint ensures compatibility with these non-compliant clients without requiring them to be updated.

1 files changed, 27 insertions, 0 deletions

diff --git a/apps/mcp/src/index.ts b/apps/mcp/src/index.ts
index e2fea661..a1fe7bac 100644
--- a/apps/mcp/src/index.ts
+++ b/apps/mcp/src/index.ts
@@ -63,6 +63,33 @@ app.get("/.well-known/oauth-protected-resource", (c) => {
 	})
 })
 
+// Proxy endpoint for MCP clients that don't follow the spec correctly
+// Some clients look for oauth-authorization-server on the MCP server domain
+// instead of following the authorization_servers array
+app.get("/.well-known/oauth-authorization-server", async (c) => {
+	const apiUrl = c.env.API_URL || DEFAULT_API_URL
+
+	try {
+		// Fetch the authorization server metadata from the main API
+		const response = await fetch(
+			`${apiUrl}/.well-known/oauth-authorization-server`,
+		)
+
+		if (!response.ok) {
+			return c.json(
+				{ error: "Failed to fetch authorization server metadata" },
+				response.status,
+			)
+		}
+
+		const metadata = await response.json()
+		return c.json(metadata)
+	} catch (error) {
+		console.error("Error fetching OAuth authorization server metadata:", error)
+		return c.json({ error: "Internal server error" }, 500)
+	}
+})
+
 const mcpHandler = SupermemoryMCP.mount("/mcp", {
 	binding: "MCP_SERVER",
 	corsOptions: {