mcp-oauth-token-request-when-using-proxyoauthserverprovider-the-token-endp-d4cd6cbf

THEN Modify the exchangeAuthorizationCode method in ProxyOAuthServerProvider to include the same redirect_uri that was used during the authorization request. The redirect_uri must be sent as a parameter in the POST request to the token endpoint. This ensures compliance with the OAuth 2.0 spec and resolves 400/500 errors from providers like Amazon Cognito.

// Inside exchangeAuthorizationCode, add redirect_uri to token request params
const tokenResponse = await fetch(tokenEndpoint, {
  method: 'POST',
  headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
  body: new URLSearchParams({
    grant_type: 'authorization_code',
    code: code,
    redirect_uri: redirectUri, // This line was missing
    client_id: clientId,
    client_secret: clientSecret
  })
});