diff --git a/.changeset/guard-prime-before-init.md b/.changeset/guard-prime-before-init.md
new file mode 100644
index 0000000..e402c66
--- /dev/null
+++ b/.changeset/guard-prime-before-init.md
@@ -0,0 +1,5 @@
+---
+"@onkernel/managed-auth-react": patch
+---
+
+Disable the consent action while the handoff exchange and initial session state load, preventing early interactions from being dropped.
diff --git a/packages/managed-auth-react/src/KernelManagedAuth.test.tsx b/packages/managed-auth-react/src/KernelManagedAuth.test.tsx
new file mode 100644
index 0000000..0a92e78
--- /dev/null
+++ b/packages/managed-auth-react/src/KernelManagedAuth.test.tsx
@@ -0,0 +1,61 @@
+import { afterEach, describe, expect, test } from "bun:test";
+import { createElement } from "react";
+import { act, create, type ReactTestRenderer } from "react-test-renderer";
+import { KernelManagedAuth } from "./KernelManagedAuth";
+
+let renderer: ReactTestRenderer | null = null;
+
+afterEach(() => {
+  renderer?.unmount();
+  renderer = null;
+});
+
+function pendingExchangeFetch(): typeof fetch {
+  const pendingExchange = new Promise<Response>(() => {});
+  return (async (
+    input: RequestInfo | URL,
+    init?: RequestInit,
+  ): Promise<Response> => {
+    const url = String(input);
+    if (url.endsWith("/exchange")) return pendingExchange;
+    throw new Error(`Unexpected request: ${init?.method} ${url}`);
+  }) as typeof fetch;
+}
+
+describe("KernelManagedAuth initialization", () => {
+  test("disables the consent action while the session initializes", () => {
+    act(() => {
+      renderer = create(
+        createElement(KernelManagedAuth, {
+          sessionId: "session-id",
+          handoffCode: "handoff-code",
+          fetch: pendingExchangeFetch(),
+        }),
+      );
+    });
+
+    const output = JSON.stringify(renderer!.toJSON());
+    const button = renderer!.root.findByType("button");
+    expect(output).toContain("Preparing secure sign-in");
+    expect(output).not.toContain("Sign in to ");
+    expect(button.props.disabled).toBe(true);
+    expect(button.children).toEqual(["Loading..."]);
+  });
+
+  test("does not show consent while a skip-prime session initializes", () => {
+    act(() => {
+      renderer = create(
+        createElement(KernelManagedAuth, {
+          sessionId: "session-id",
+          handoffCode: "handoff-code",
+          fetch: pendingExchangeFetch(),
+          appearance: { layout: { skipPrimeStep: true } },
+        }),
+      );
+    });
+
+    const output = JSON.stringify(renderer!.toJSON());
+    expect(output).toContain("Discovering login requirements...");
+    expect(renderer!.root.findAllByType("button")).toHaveLength(0);
+  });
+});
diff --git a/packages/managed-auth-react/src/KernelManagedAuth.tsx b/packages/managed-auth-react/src/KernelManagedAuth.tsx
index 8be1d02..7ba9df4 100644
--- a/packages/managed-auth-react/src/KernelManagedAuth.tsx
+++ b/packages/managed-auth-react/src/KernelManagedAuth.tsx
@@ -74,6 +74,7 @@ function KernelManagedAuthInner({
   const {
     state,
     uiState,
+    isInitializing,
     submitError,
     initError,
     isSubmitting,
@@ -91,7 +92,7 @@ function KernelManagedAuthInner({
       <StepPrime
         targetDomain={targetDomain}
         onContinue={startFlow}
-        isLoading={isSubmitting}
+        isLoading={isInitializing || isSubmitting}
         layout={appearance?.layout}
       />
     );
diff --git a/packages/managed-auth-react/src/components/StepPrime.tsx b/packages/managed-auth-react/src/components/StepPrime.tsx
index ae407dd..50cccd7 100644
--- a/packages/managed-auth-react/src/components/StepPrime.tsx
+++ b/packages/managed-auth-react/src/components/StepPrime.tsx
@@ -30,6 +30,13 @@ export function StepPrime({
   const displayName =
     primaryLabel.charAt(0).toUpperCase() + primaryLabel.slice(1);
 
+  const isInitializing = isLoading && !targetDomain;
+  const title = isInitializing
+    ? l.primeLoadingTitle
+    : l.primeTitle(displayName);
+  const subtitle = isInitializing
+    ? l.primeLoadingSubtitle
+    : l.primeSubtitle(siteName);
   const showSecurityCard = layout?.showSecurityCard !== false;
   const showLegalText = layout?.showLegalText !== false;
 
@@ -40,8 +47,8 @@ export function StepPrime({
       </div>
 
       <div className="kma-step__header">
-        <h1 {...slot("title", "kma-title")}>{l.primeTitle(displayName)}</h1>
-        <p {...slot("subtitle", "kma-subtitle")}>{l.primeSubtitle(siteName)}</p>
+        <h1 {...slot("title", "kma-title")}>{title}</h1>
+        <p {...slot("subtitle", "kma-subtitle")}>{subtitle}</p>
       </div>
 
       {showSecurityCard && (
diff --git a/packages/managed-auth-react/src/localization/defaults.ts b/packages/managed-auth-react/src/localization/defaults.ts
index 9dddebc..96d759f 100644
--- a/packages/managed-auth-react/src/localization/defaults.ts
+++ b/packages/managed-auth-react/src/localization/defaults.ts
@@ -5,6 +5,8 @@ export const DEFAULT_LOCALIZATION: Localizer = {
   primeSubtitle: (site) => `Enter your ${site} credentials to continue`,
   primeContinueButton: "Continue",
   primeLoadingButton: "Loading...",
+  primeLoadingTitle: "Preparing secure sign-in",
+  primeLoadingSubtitle: "Loading connection details...",
   securityEncryption: "Your credentials are encrypted end-to-end",
   // Matches the second sentence of `credentialSafetyNotice` so the consent
   // step and the form footer make the same promise verbatim.
diff --git a/packages/managed-auth-react/src/localization/types.ts b/packages/managed-auth-react/src/localization/types.ts
index 73d28a7..a7a6007 100644
--- a/packages/managed-auth-react/src/localization/types.ts
+++ b/packages/managed-auth-react/src/localization/types.ts
@@ -10,6 +10,8 @@ export interface Localization {
   primeSubtitle?: (siteName: string) => string;
   primeContinueButton?: string;
   primeLoadingButton?: string;
+  primeLoadingTitle?: string;
+  primeLoadingSubtitle?: string;
   securityEncryption?: string;
   securityNoThirdParty?: string;
   legalPrefix?: string;
diff --git a/packages/managed-auth-react/src/session/useManagedAuthSession.test.ts b/packages/managed-auth-react/src/session/useManagedAuthSession.test.ts
index def4b85..e78c5f4 100644
--- a/packages/managed-auth-react/src/session/useManagedAuthSession.test.ts
+++ b/packages/managed-auth-react/src/session/useManagedAuthSession.test.ts
@@ -140,6 +140,71 @@ async function renderSession(
   };
 }
 
+describe("useManagedAuthSession initialization", () => {
+  test("reports initialization until the session is ready", async () => {
+    const exchange = deferred<Response>();
+    let value: ManagedAuthSessionValue | null = null;
+
+    const fetchImpl = (async (
+      input: RequestInfo | URL,
+      init?: RequestInit,
+    ): Promise<Response> => {
+      const url = String(input);
+      if (url.endsWith("/exchange")) return exchange.promise;
+      if (init?.method === "GET") return response(awaitingInputState());
+      throw new Error(`Unexpected request: ${init?.method} ${url}`);
+    }) as typeof fetch;
+
+    function Harness() {
+      value = useManagedAuthSession({
+        sessionId: "session-id",
+        handoffCode: "handoff-code",
+        fetch: fetchImpl,
+      });
+      return null;
+    }
+
+    act(() => {
+      renderer = create(createElement(Harness));
+    });
+
+    expect(value!.uiState).toBe("prime");
+    expect(value!.isInitializing).toBe(true);
+
+    await act(async () => {
+      exchange.resolve(response({ jwt: "jwt" }));
+      await flushPromises();
+    });
+
+    expect(value!.uiState).toBe("prime");
+    expect(value!.isInitializing).toBe(false);
+  });
+
+  test("leaves initialization when the handoff exchange fails", async () => {
+    let value: ManagedAuthSessionValue | null = null;
+    const fetchImpl = (async (_input: RequestInfo | URL, _init?: RequestInit) =>
+      response({ message: "Invalid handoff" }, 401)) as typeof fetch;
+
+    function Harness() {
+      value = useManagedAuthSession({
+        sessionId: "session-id",
+        handoffCode: "handoff-code",
+        fetch: fetchImpl,
+      });
+      return null;
+    }
+
+    await act(async () => {
+      renderer = create(createElement(Harness));
+      await flushPromises();
+    });
+
+    expect(value!.uiState).toBe("error");
+    expect(value!.isInitializing).toBe(false);
+    expect(value!.initError).toBe("Invalid handoff");
+  });
+});
+
 describe("useManagedAuthSession stale interaction recovery", () => {
   test("does not reconnect after the session is unmounted", async () => {
     const refresh = deferred<Response>();
diff --git a/packages/managed-auth-react/src/session/useManagedAuthSession.ts b/packages/managed-auth-react/src/session/useManagedAuthSession.ts
index a6cc575..238455d 100644
--- a/packages/managed-auth-react/src/session/useManagedAuthSession.ts
+++ b/packages/managed-auth-react/src/session/useManagedAuthSession.ts
@@ -64,6 +64,7 @@ export interface ManagedAuthSessionOptions extends ApiClientOptions {
 export interface ManagedAuthSessionValue {
   state: ManagedAuthResponse | null;
   uiState: UIState;
+  isInitializing: boolean;
   isSubmitting: boolean;
   isReconnecting: boolean;
   submitError: string | null;
@@ -86,7 +87,10 @@ export function useManagedAuthSession(
 
   const [jwt, setJwt] = useState<string | null>(null);
   const [state, setState] = useState<ManagedAuthResponse | null>(null);
-  const [uiState, setUIState] = useState<UIState>("prime");
+  const [uiState, setUIState] = useState<UIState>(
+    autoStart ? "discovering" : "prime",
+  );
+  const [isInitializing, setIsInitializing] = useState(true);
   const [isSubmitting, setIsSubmitting] = useState(false);
   const [isReconnecting, setIsReconnecting] = useState(false);
   const [submitError, setSubmitError] = useState<string | null>(null);
@@ -308,7 +312,15 @@ export function useManagedAuthSession(
     terminalRef.current = false;
     reconnectAttemptsRef.current = 0;
     callbackFiredRef.current = { success: false, error: false };
+    stateRef.current = null;
+    setJwt(null);
+    setState(null);
+    setUIState(autoStart ? "discovering" : "prime");
+    setIsInitializing(true);
     setIsSubmitting(false);
+    setIsReconnecting(false);
+    setSubmitError(null);
+    setInitError(null);
 
     const ref = { key: exchangeKey, active: true };
     exchangeRef.current = ref;
@@ -328,6 +340,7 @@ export function useManagedAuthSession(
         if (exchangeRef.current !== ref || !ref.active) return;
         stateRef.current = initial;
         setState(initial);
+        setIsInitializing(false);
         const derived = deriveUIState(initial);
         if (isTerminal(derived)) {
           terminalRef.current = true;
@@ -356,6 +369,7 @@ export function useManagedAuthSession(
         if (exchangeRef.current !== ref || !ref.active) return;
         const message =
           err instanceof Error ? err.message : "Failed to start session";
+        setIsInitializing(false);
         setInitError(message);
         setUIState("error");
         terminalRef.current = true;
@@ -530,6 +544,7 @@ export function useManagedAuthSession(
   return {
     state,
     uiState,
+    isInitializing,
     isSubmitting,
     isReconnecting,
     submitError,