diff --git a/clients/web/src/test/core/auth/runner-interactive-oauth.test.ts b/clients/web/src/test/core/auth/runner-interactive-oauth.test.ts
index 05d3f810..eac480ee 100644
--- a/clients/web/src/test/core/auth/runner-interactive-oauth.test.ts
+++ b/clients/web/src/test/core/auth/runner-interactive-oauth.test.ts
@@ -84,6 +84,34 @@ describe("runRunnerInteractiveOAuth", () => {
     expect(client.completeOAuthFlow).not.toHaveBeenCalled();
   });
 
+  it("clears the callback timeout on already_authorized", async () => {
+    vi.useFakeTimers();
+    try {
+      const client = mockClient({
+        authenticate: vi.fn(async () => undefined),
+      });
+      const redirectUrlProvider = { redirectUrl: "" };
+
+      const result = await runRunnerInteractiveOAuth({
+        client,
+        redirectUrlProvider,
+        callbackListen: {
+          hostname: "127.0.0.1",
+          port: 6276,
+          pathname: "/oauth/callback",
+        },
+        callbackTimeoutMs: 60_000,
+        createCallbackServer: () => createMockCallbackServer(handlers),
+      });
+
+      expect(result).toEqual({ kind: "already_authorized" });
+      expect(vi.getTimerCount()).toBe(0);
+      await vi.advanceTimersByTimeAsync(60_000);
+    } finally {
+      vi.useRealTimers();
+    }
+  });
+
   it("completes connect-time OAuth via authenticate and callback", async () => {
     const redirectUrlProvider = { redirectUrl: "" };
     const client = mockClient({
diff --git a/clients/web/src/test/core/mcp/oauthManager.test.ts b/clients/web/src/test/core/mcp/oauthManager.test.ts
index 328ceca8..13fe1bc4 100644
--- a/clients/web/src/test/core/mcp/oauthManager.test.ts
+++ b/clients/web/src/test/core/mcp/oauthManager.test.ts
@@ -1215,9 +1215,6 @@ describe("OAuthManager", () => {
     });
 
     it("returns satisfied for EMA insufficient_scope after user confirms", async () => {
-      const silentSpy = vi
-        .spyOn(emaFlow, "trySilentEmaAuth")
-        .mockResolvedValue({ status: "success" });
       const params = createMockParams({
         enterpriseManagedAuth: {
           idp: {
@@ -1237,6 +1234,14 @@ describe("OAuthManager", () => {
         token_type: "Bearer",
         scope: "mcp",
       });
+      const silentSpy = vi.spyOn(emaFlow, "trySilentEmaAuth").mockImplementation(async () => {
+        storageOf(params).getTokens.mockResolvedValue({
+          access_token: "tok",
+          token_type: "Bearer",
+          scope: "mcp weather:read",
+        });
+        return { status: "success" };
+      });
       const manager = new OAuthManager(params);
       manager.setOAuthConfig({ enterpriseManaged: true });
 
@@ -1257,6 +1262,51 @@ describe("OAuthManager", () => {
       silentSpy.mockRestore();
     });
 
+    it("does not persist union scope or return satisfied when silent EMA mint is down-scoped", async () => {
+      const silentSpy = vi
+        .spyOn(emaFlow, "trySilentEmaAuth")
+        .mockResolvedValue({ status: "success" });
+      const authUrl = new URL("https://idp.example.com/authorize?state=ema");
+      const startSpy = vi
+        .spyOn(emaFlow, "startEmaIdpAuthorization")
+        .mockResolvedValue(authUrl);
+      const params = createMockParams({
+        enterpriseManagedAuth: {
+          idp: {
+            issuer: "https://idp.example.com",
+            clientId: "app-client",
+            clientSecret: "secret",
+          },
+        },
+      });
+      storageOf(params).getScope.mockReturnValue("mcp");
+      storageOf(params).getTokens.mockResolvedValue({
+        access_token: "tok",
+        token_type: "Bearer",
+        scope: "mcp",
+      });
+      const manager = new OAuthManager(params);
+      manager.setOAuthConfig({ enterpriseManaged: true });
+
+      const outcome = await manager.handleAuthChallenge(
+        {
+          reason: "insufficient_scope",
+          requiredScopes: ["weather:read"],
+        },
+        { confirmedStepUp: true },
+      );
+
+      expect(outcome).toEqual(
+        expect.objectContaining({
+          kind: "interactive",
+          authorizationUrl: authUrl,
+        }),
+      );
+      expect(storageOf(params).saveScope).not.toHaveBeenCalled();
+      silentSpy.mockRestore();
+      startSpy.mockRestore();
+    });
+
     it("completeOAuthFlow mints EMA tokens with pending step-up union scope", async () => {
       const silentSpy = vi
         .spyOn(emaFlow, "trySilentEmaAuth")
diff --git a/core/auth/node/runner-interactive-oauth.ts b/core/auth/node/runner-interactive-oauth.ts
index ab6a9aad..77de2b17 100644
--- a/core/auth/node/runner-interactive-oauth.ts
+++ b/core/auth/node/runner-interactive-oauth.ts
@@ -58,6 +58,8 @@ export async function runRunnerInteractiveOAuth(
     flowReject = reject;
   });
 
+  let timeoutId: ReturnType<typeof setTimeout> | undefined;
+
   try {
     const { redirectUrl } = await server.start({
       hostname: options.callbackListen.hostname,
@@ -85,7 +87,6 @@ export async function runRunnerInteractiveOAuth(
 
     const timeoutMs =
       options.callbackTimeoutMs ?? DEFAULT_RUNNER_INTERACTIVE_OAUTH_TIMEOUT_MS;
-    let timeoutId: ReturnType<typeof setTimeout> | undefined;
     const waitForCallback = Promise.race([
       flowDone.finally(() => {
         if (timeoutId !== undefined) {
@@ -131,6 +132,9 @@ export async function runRunnerInteractiveOAuth(
 
     return { kind: "success" };
   } finally {
+    if (timeoutId !== undefined) {
+      clearTimeout(timeoutId);
+    }
     await server.stop().catch(() => {});
   }
 }
diff --git a/core/mcp/oauthManager.ts b/core/mcp/oauthManager.ts
index 8d38362d..96c95e19 100644
--- a/core/mcp/oauthManager.ts
+++ b/core/mcp/oauthManager.ts
@@ -602,13 +602,13 @@ export class OAuthManager {
     if (enriched.reason === "insufficient_scope") {
       const silent = await trySilentEmaAuth(config);
       if (silent.status === "success") {
-        if (enriched.authorizationScopes?.length) {
-          await this.oauthConfig.storage!.saveScope(
-            this.getServerUrl(),
-            enriched.authorizationScopes.join(" "),
-          );
-        }
         if (await this.checkAuthChallengeSatisfied(enriched)) {
+          if (enriched.authorizationScopes?.length) {
+            await this.oauthConfig.storage!.saveScope(
+              this.getServerUrl(),
+              enriched.authorizationScopes.join(" "),
+            );
+          }
           return { kind: "satisfied" };
         }
       }