diff --git a/src/browser/routes/agent.snapshot.test.ts b/src/browser/routes/agent.snapshot.test.ts
new file mode 100644
index 00000000000..77b802bdf7d
--- /dev/null
+++ b/src/browser/routes/agent.snapshot.test.ts
@@ -0,0 +1,117 @@
+import { describe, expect, it, vi } from "vitest";
+import { resolveTargetIdAfterNavigate } from "./agent.snapshot.js";
+
+type Tab = { targetId: string; url: string };
+
+function staticListTabs(tabs: Tab[]): () => Promise<Tab[]> {
+  return async () => tabs;
+}
+
+describe("resolveTargetIdAfterNavigate", () => {
+  it("returns original targetId when old target still exists (no swap)", async () => {
+    const result = await resolveTargetIdAfterNavigate({
+      oldTargetId: "old-123",
+      navigatedUrl: "https://example.com",
+      listTabs: staticListTabs([
+        { targetId: "old-123", url: "https://example.com" },
+        { targetId: "other-456", url: "https://other.com" },
+      ]),
+    });
+    expect(result).toBe("old-123");
+  });
+
+  it("resolves new targetId when old target is gone (renderer swap)", async () => {
+    const result = await resolveTargetIdAfterNavigate({
+      oldTargetId: "old-123",
+      navigatedUrl: "https://example.com",
+      listTabs: staticListTabs([{ targetId: "new-456", url: "https://example.com" }]),
+    });
+    expect(result).toBe("new-456");
+  });
+
+  it("prefers non-stale targetId when multiple tabs share the URL", async () => {
+    const result = await resolveTargetIdAfterNavigate({
+      oldTargetId: "old-123",
+      navigatedUrl: "https://example.com",
+      listTabs: staticListTabs([
+        { targetId: "preexisting-000", url: "https://example.com" },
+        { targetId: "fresh-777", url: "https://example.com" },
+      ]),
+    });
+    // Both differ from old targetId; the first non-stale match wins.
+    expect(result).toBe("preexisting-000");
+  });
+
+  it("retries and resolves targetId when first listTabs has no URL match", async () => {
+    vi.useFakeTimers();
+    let calls = 0;
+
+    const result$ = resolveTargetIdAfterNavigate({
+      oldTargetId: "old-123",
+      navigatedUrl: "https://delayed.com",
+      listTabs: async () => {
+        calls++;
+        if (calls === 1) {
+          return [{ targetId: "unrelated-1", url: "https://unrelated.com" }];
+        }
+        return [{ targetId: "delayed-999", url: "https://delayed.com" }];
+      },
+    });
+
+    await vi.advanceTimersByTimeAsync(800);
+    const result = await result$;
+
+    expect(result).toBe("delayed-999");
+    expect(calls).toBe(2);
+
+    vi.useRealTimers();
+  });
+
+  it("falls back to original targetId when no match found after retry", async () => {
+    vi.useFakeTimers();
+
+    const result$ = resolveTargetIdAfterNavigate({
+      oldTargetId: "old-123",
+      navigatedUrl: "https://no-match.com",
+      listTabs: staticListTabs([
+        { targetId: "unrelated-1", url: "https://unrelated.com" },
+        { targetId: "unrelated-2", url: "https://unrelated2.com" },
+      ]),
+    });
+
+    await vi.advanceTimersByTimeAsync(800);
+    const result = await result$;
+
+    expect(result).toBe("old-123");
+
+    vi.useRealTimers();
+  });
+
+  it("falls back to single remaining tab when no URL match after retry", async () => {
+    vi.useFakeTimers();
+
+    const result$ = resolveTargetIdAfterNavigate({
+      oldTargetId: "old-123",
+      navigatedUrl: "https://single-tab.com",
+      listTabs: staticListTabs([{ targetId: "only-tab", url: "https://some-other.com" }]),
+    });
+
+    await vi.advanceTimersByTimeAsync(800);
+    const result = await result$;
+
+    expect(result).toBe("only-tab");
+
+    vi.useRealTimers();
+  });
+
+  it("falls back to original targetId when listTabs throws", async () => {
+    const result = await resolveTargetIdAfterNavigate({
+      oldTargetId: "old-123",
+      navigatedUrl: "https://error.com",
+      listTabs: async () => {
+        throw new Error("CDP connection lost");
+      },
+    });
+    expect(result).toBe("old-123");
+  });
+});
diff --git a/src/browser/routes/agent.snapshot.ts b/src/browser/routes/agent.snapshot.ts
index 3fb076bc061..7739caa051e 100644
--- a/src/browser/routes/agent.snapshot.ts
+++ b/src/browser/routes/agent.snapshot.ts
@@ -48,6 +48,41 @@ async function saveBrowserMediaResponse(params: {
   });
 }
 
+/** Resolve the correct targetId after a navigation that may trigger a renderer swap. */
+export async function resolveTargetIdAfterNavigate(opts: {
+  oldTargetId: string;
+  navigatedUrl: string;
+  listTabs: () => Promise<Array<{ targetId: string; url: string }>>;
+}): Promise<string> {
+  let currentTargetId = opts.oldTargetId;
+  try {
+    const refreshed = await opts.listTabs();
+    if (!refreshed.some((t) => t.targetId === opts.oldTargetId)) {
+      // Renderer swap: old target gone, resolve the replacement.
+      // Prefer a URL match whose targetId differs from the old one
+      // to avoid picking a pre-existing tab when multiple share the URL.
+      const byUrl = refreshed.filter((t) => t.url === opts.navigatedUrl);
+      const replaced = byUrl.find((t) => t.targetId !== opts.oldTargetId) ?? byUrl[0];
+      if (replaced) {
+        currentTargetId = replaced.targetId;
+      } else {
+        await new Promise((r) => setTimeout(r, 800));
+        const retried = await opts.listTabs();
+        const match =
+          retried.find((t) => t.url === opts.navigatedUrl && t.targetId !== opts.oldTargetId) ??
+          retried.find((t) => t.url === opts.navigatedUrl) ??
+          (retried.length === 1 ? retried[0] : null);
+        if (match) {
+          currentTargetId = match.targetId;
+        }
+      }
+    }
+  } catch {
+    // Best-effort: fall back to pre-navigation targetId
+  }
+  return currentTargetId;
+}
+
 export function registerBrowserAgentSnapshotRoutes(
   app: BrowserRouteRegistrar,
   ctx: BrowserRouteContext,
@@ -65,14 +100,19 @@ export function registerBrowserAgentSnapshotRoutes(
       ctx,
       targetId,
       feature: "navigate",
-      run: async ({ cdpUrl, tab, pw }) => {
+      run: async ({ cdpUrl, tab, pw, profileCtx }) => {
         const result = await pw.navigateViaPlaywright({
           cdpUrl,
           targetId: tab.targetId,
           url,
           ...withBrowserNavigationPolicy(ctx.state().resolved.ssrfPolicy),
         });
-        res.json({ ok: true, targetId: tab.targetId, ...result });
+        const currentTargetId = await resolveTargetIdAfterNavigate({
+          oldTargetId: tab.targetId,
+          navigatedUrl: result.url,
+          listTabs: () => profileCtx.listTabs(),
+        });
+        res.json({ ok: true, targetId: currentTargetId, ...result });
       },
     });
   });