diff --git a/packages/core/src/plugin/browser/index.ts b/packages/core/src/plugin/browser/index.ts
index 1dffe3d7a64..d3eb80d8f9b 100644
--- a/packages/core/src/plugin/browser/index.ts
+++ b/packages/core/src/plugin/browser/index.ts
@@ -44,8 +44,10 @@ export default Plugin.define({
               const browser = yield* Effect.acquireRelease(
                 Effect.gen(function* () {
                   const closed = yield* Deferred.make<void>()
-                  if (!active || browsers.has(input.sessionID))
-                    return yield* Effect.fail(call.error("unavailable", "Browser is unavailable.", {}))
+                  if (!active) return yield* Effect.fail(call.error("unavailable", "Browser is unavailable.", {}))
+                  // The newest desktop attachment wins so a re-register that races the
+                  // previous connection's teardown does not leave the session detached.
+                  yield* close(input.sessionID)
                   const browser: Attachment = {
                     connectionID: input.connectionID,
                     state: null,
diff --git a/packages/sdk/test/browser-plugin.test.ts b/packages/sdk/test/browser-plugin.test.ts
index 0c129aeb440..159d1cbe298 100644
--- a/packages/sdk/test/browser-plugin.test.ts
+++ b/packages/sdk/test/browser-plugin.test.ts
@@ -113,10 +113,13 @@ test(
       expect(yield* host.execute({ type: "open" }).pipe(Effect.flip)).toMatchObject({
         message: "No desktop browser is connected.",
       })
+      const stale = yield* host.attach("stale")
+      // A newer attachment for the same session replaces the previous one.
       const attached = yield* host.attach("first")
-      expect(
-        yield* host.rpc.attach({ ...attached.input, connectionID: "duplicate" }, options).pipe(Effect.flip),
-      ).toMatchObject({ type: "unavailable" })
+      yield* Fiber.join(stale.lifetime).pipe(Effect.timeout("5 seconds"))
+      expect(yield* host.rpc.state({ ...stale.input, state }, options).pipe(Effect.flip)).toMatchObject({
+        type: "unavailable",
+      })
       const other = Location.Ref.make({ directory: AbsolutePath.make(path.join(host.location.directory, "other")) })
       yield* Effect.promise(() => mkdir(other.directory))
       yield* host.opencode.plugin.list({ location: other })