@@ -1,9 +1,12 @@
+import { DeviceOperationError } from "@t3tools/contracts";
 import * as Crypto from "effect/Crypto";
+import * as Duration from "effect/Duration";
 import * as Effect from "effect/Effect";
 import * as Hex from "effect/encoding/Hex";
 import * as Schema from "effect/Schema";
 import * as FileSystem from "effect/FileSystem";
 import * as Path from "effect/Path";
+import { HttpClient, HttpClientRequest, HttpClientResponse } from "effect/http";
 
 import type { AgentDaemonEndpoint } from "./DeviceHost.ts";
 
@@ -62,3 +65,36 @@ export const writeAgentDeviceConfig = Effect.fn("AgentDeviceTarget.writeConfig")
     yield* fs.rename(temporary, file);
   }).pipe(Effect.ensuring(fs.remove(temporary, { force: true }).pipe(Effect.ignore)));
 });
+
+const AgentCloseResult = Schema.Union([
+  Schema.Struct({ result: Schema.Struct({ ok: Schema.Literal(true) }) }),
+  Schema.Struct({
+    error: Schema.Struct({
+      data: Schema.Struct({ code: Schema.Literal("SESSION_NOT_FOUND") }),
+    }),
+  }),
+]);
+
+/** Ends an agent-device session on a running daemon; an already-released session succeeds. */
+export const releaseAgentDeviceSession =
+  (http: HttpClient.HttpClient, endpoint: AgentDaemonEndpoint) => (session: string) =>
+    HttpClientRequest.post(`${endpoint.baseUrl}/rpc`).pipe(
+      HttpClientRequest.bearerToken(endpoint.token),
+      HttpClientRequest.bodyJson({
+        jsonrpc: "2.0",
+        id: session,
+        method: "agent_device.command",
+        params: { command: "close", session, positionals: [], flags: {} },
+      }),
+      Effect.flatMap((request) => http.pipe(HttpClient.withScope).execute(request)),
+      // agent-device reports an already-released session as HTTP 404.
+      Effect.filterOrElse((response) => response.status === 404, HttpClientResponse.filterStatusOk),
+      Effect.flatMap(HttpClientResponse.schemaBodyJson(AgentCloseResult)),
+      Effect.scoped,
+      Effect.timeout(Duration.seconds(15)),
+      Effect.asVoid,
+      Effect.mapError(
+        (cause) =>
+          new DeviceOperationError({ operation: "close", reason: "request_failed", cause }),
+      ),
+    );
@@ -145,6 +145,16 @@ export interface DeviceOperations {
 
 export interface DeviceHostReady {
   readonly nodePath: string;
+  /**
+   * Ends an agent-device session on the daemon that serves `deviceId`. Hosts
+   * with a shared daemon provide it only while that daemon runs; hosts with a
+   * daemon per device succeed when the device's daemon is gone. Cleanup never
+   * starts a daemon or a device.
+   */
+  readonly releaseAgentSession?: (
+    session: string,
+    deviceId: string,
+  ) => Effect.Effect<void, DeviceOperationError>;
   readonly hub: DeviceHubEndpoint;
   readonly devices: DeviceOperations;
   readonly run: (
 
@@ -6,6 +6,7 @@ import * as NodeCrypto from "@effect/platform-node/NodeCrypto";
 import * as Effect from "effect/Effect";
 import { HttpClient, HttpClientResponse } from "effect/http";
 import * as ServerSettings from "../serverSettings.ts";
+import { releaseAgentDeviceSession } from "./AgentDeviceTarget.ts";
 import * as DeviceHost from "./DeviceHost.ts";
 import { makeDeviceHubOperations } from "./DeviceHubOperations.ts";
 import * as DeviceService from "./DeviceService.ts";
@@ -16,19 +17,23 @@ it.effect("keeps hosts independent when serials collide and another host fails",
       Effect.succeed(
         HttpClientResponse.fromWeb(
           request,
-          Response.json({
-            simulators: [],
-            emulators: [
-              {
-                id: "emulator-5554",
-                name: "Pixel",
-                version: "36",
-                platform: "android",
-                booted: true,
-                physical: false,
-              },
-            ],
-          }),
+          Response.json(
+            request.url.endsWith("/rpc")
+              ? { result: { ok: true } }
+              : {
+                  simulators: [],
+                  emulators: [
+                    {
+                      id: "emulator-5554",
+                      name: "Pixel",
+                      version: "36",
+                      platform: "android",
+                      booted: true,
+                      physical: false,
+                    },
+                  ],
+                },
+          ),
         ),
       ),
     );
@@ -50,6 +55,10 @@ it.effect("keeps hosts independent when serials collide and another host fails",
           androidAvailable: Effect.succeed(true),
         }),
         agentDevice: { baseUrl: `http://${id}`, token: "test", entryPath: "/agent-device" },
+        releaseAgentSession: releaseAgentDeviceSession(http, {
+          baseUrl: `http://${id}`,
+          token: "test",
+        }),
         run,
         helpers: { serveSimAxSettings: null, serveSimCli: null },
       };