diff --git a/packages/server/src/server/agent/providers/opencode-agent.test.ts b/packages/server/src/server/agent/providers/opencode-agent.test.ts
index e5ef7f681..26f3b89cb 100644
--- a/packages/server/src/server/agent/providers/opencode-agent.test.ts
+++ b/packages/server/src/server/agent/providers/opencode-agent.test.ts
@@ -91,6 +91,40 @@ function providerAssistantMessages(events: AgentStreamEvent[], text: string): Ag
   );
 }
 
+type TurnEventSignature = [type: AgentStreamEvent["type"], turnId: string | undefined];
+
+function turnEventSignatures(events: AgentStreamEvent[]): TurnEventSignature[] {
+  return events.map((event) => [event.type, "turnId" in event ? event.turnId : undefined]);
+}
+
+function userMessageEvents(params: {
+  sessionId: string;
+  messageId: string;
+  text: string;
+}): unknown[] {
+  return [
+    {
+      type: "message.updated",
+      properties: {
+        info: { id: params.messageId, sessionID: params.sessionId, role: "user" },
+      },
+    },
+    {
+      type: "message.part.updated",
+      properties: {
+        part: {
+          id: `part_${params.messageId}`,
+          sessionID: params.sessionId,
+          messageID: params.messageId,
+          type: "text",
+          text: params.text,
+          time: { start: 1, end: 2 },
+        },
+      },
+    },
+  ];
+}
+
 function assistantTurnEvents({
   sessionId = "session-1",
   text = "Hello from OpenCode",
@@ -123,6 +157,29 @@ function assistantTurnEvents({
   ];
 }
 
+async function createParentSession(
+  sessionId: string,
+  configure?: (openCode: TestOpenCodeClient) => void,
+): Promise<{
+  readonly parent: Awaited<ReturnType<OpenCodeAgentClient["createSession"]>>;
+  readonly openCode: TestOpenCodeClient;
+}> {
+  const runtime = new TestOpenCodeHarness();
+  const openCode = new TestOpenCodeClient();
+  openCode.sessionCreateResponse = { data: { id: sessionId } };
+  configure?.(openCode);
+  runtime.enqueueClient(openCode);
+  const client = new OpenCodeAgentClient(createTestLogger(), undefined, {
+    serverManager: runtime,
+    createClient: runtime.createClient,
+  });
+  const parent = await client.createSession({
+    provider: "opencode",
+    cwd: "/workspace/repo",
+  });
+  return { parent, openCode };
+}
+
 function manualCompactEvents({
   sessionId = "session-1",
   summaryText = "## Goal\n- Preserve context while continuing the task.",
@@ -1844,56 +1901,91 @@ describe("OpenCode adapter startTurn error handling", () => {
     }
   });
 
-  test("delays the next prompt until a slow interrupt abort settles", async () => {
-    vi.useFakeTimers();
-    const abortDeferred = createTestDeferred<{ data: boolean; error: undefined }>();
-    const promptAsync = vi.fn().mockResolvedValue({ data: {}, error: undefined });
-    const abort = vi
-      .fn()
-      .mockReturnValueOnce(abortDeferred.promise)
-      .mockResolvedValue({ data: true, error: undefined });
-    const fakeClient = {
-      global: {
-        event: vi.fn().mockImplementation(
-          async (options: {
-            signal: AbortSignal;
-          }): Promise<{ stream: AsyncIterable<OpenCodeEvent> }> => ({
-            stream: abortableOpenCodeStream(options.signal),
-          }),
-        ),
-      },
-      session: {
-        promptAsync,
-        abort,
-      },
-    } as never;
+  test("retries abort and waits for provider idle before starting the next prompt", async () => {
+    const { parent: session, openCode } = await createParentSession("ses_unit_test");
+    openCode.sessionPromptAsyncEvents = [];
+    openCode.sessionAbortImplementation = async () => {
+      if (openCode.calls.sessionAbort.length === 1) {
+        throw new Error("abort transport failed");
+      }
+      openCode.emitEvent({
+        type: "session.idle",
+        properties: { sessionID: "ses_unit_test" },
+      });
+      return { data: true };
+    };
+    try {
+      await session.startTurn("first");
+      await session.interrupt();
+      expect(openCode.calls.sessionPromptAsync).toHaveLength(1);
 
-    const session = new __openCodeInternals.OpenCodeAgentSession(
-      { provider: "opencode", cwd: "/tmp/test" },
-      fakeClient,
-      "ses_unit_test",
-      createTestLogger(),
-    );
-
-    await session.startTurn("first");
-    expect(promptAsync).toHaveBeenCalledTimes(1);
-
-    const interruptPromise = session.interrupt();
-    await vi.advanceTimersByTimeAsync(2_000);
-    await interruptPromise;
-    expect(abort).toHaveBeenCalledTimes(1);
-
-    const secondTurnPromise = session.startTurn("second");
-    await vi.advanceTimersByTimeAsync(1_000);
-    expect(promptAsync).toHaveBeenCalledTimes(1);
-
-    abortDeferred.resolve({ data: true, error: undefined });
-    await secondTurnPromise;
-    expect(promptAsync).toHaveBeenCalledTimes(2);
-
-    await session.interrupt();
-    vi.useRealTimers();
+      await session.startTurn("second");
+      expect(openCode.calls.sessionAbort).toHaveLength(2);
+      expect(openCode.calls.sessionPromptAsync).toHaveLength(2);
+    } finally {
+      await session.close();
+    }
   });
+
+  test("does not send a prompt while the previous provider turn is still stopping", async () => {
+    vi.useFakeTimers();
+    const { parent: session, openCode } = await createParentSession("ses_unit_test");
+    openCode.sessionPromptAsyncEvents = [];
+
+    try {
+      await session.startTurn("first");
+      await session.interrupt();
+
+      const secondTurn = expect(session.startTurn("second")).rejects.toThrow(
+        "OpenCode previous turn to stop",
+      );
+      await vi.advanceTimersByTimeAsync(10_000);
+      await secondTurn;
+      expect(openCode.calls.sessionPromptAsync).toHaveLength(1);
+    } finally {
+      vi.useRealTimers();
+      await session.close();
+    }
+  });
+
+  test("reconnects and confirms provider idle when the event stream ends while stopping", async () => {
+    const firstStreamEnd = createTestDeferred<void>();
+    let subscriptionCount = 0;
+    const { parent: session, openCode } = await createParentSession(
+      "ses_stream_reconnect",
+      (client) => {
+        client.globalEventImplementation = async (options) => {
+          subscriptionCount += 1;
+          const signal = (options as { signal: AbortSignal }).signal;
+          const end = subscriptionCount === 1 ? firstStreamEnd.promise : waitForAbort(signal);
+          return {
+            stream: {
+              async *[Symbol.asyncIterator]() {
+                yield { type: "server.connected", properties: {} };
+                await end;
+              },
+            },
+          };
+        };
+      },
+    );
+    openCode.sessionPromptAsyncEvents = [];
+
+    try {
+      await session.startTurn("first");
+      await session.interrupt();
+
+      const secondTurn = session.startTurn("second");
+      firstStreamEnd.resolve();
+
+      await expect(secondTurn).resolves.toEqual({ turnId: "opencode-turn-1" });
+      expect(openCode.calls.globalEvent).toHaveLength(2);
+      expect(openCode.calls.sessionStatus).toEqual([{ directory: "/workspace/repo" }]);
+      expect(openCode.calls.sessionPromptAsync).toHaveLength(2);
+    } finally {
+      await session.close();
+    }
+  }, 15_000);
 });
 
 describe("OpenCodeAgentClient env", () => {
@@ -2464,7 +2556,7 @@ describe("OpenCode provider subagent contract", () => {
     ]);
   });
 
-  test("synthesizes a turn for externally driven adopted child timeline events", async () => {
+  test("synthesizes an autonomous turn for adopted child timeline events", async () => {
     const { child, childClient, parent } = await createAdoptedChildSession();
     const completed = createTestDeferred<void>();
     const events: AgentStreamEvent[] = [];
@@ -2515,7 +2607,184 @@ describe("OpenCode provider subagent contract", () => {
     );
   });
 
-  test("synthesizes a turn for externally driven adopted child permissions", async () => {
+  test("surfaces an autonomous OpenCode wake as a new parent turn", async () => {
+    const { parent, openCode } = await createParentSession("ses_parent_plugin_wake");
+    const events: AgentStreamEvent[] = [];
+    parent.subscribe((event) => events.push(event));
+
+    try {
+      for (const event of userMessageEvents({
+        sessionId: "ses_parent_plugin_wake",
+        messageId: "msg_plugin_wake",
+        text: "<system-reminder>All background tasks are complete.</system-reminder>",
+      })) {
+        openCode.emitEvent(event);
+      }
+      openCode.emitEvent({
+        type: "session.status",
+        properties: { sessionID: "ses_parent_plugin_wake", status: { type: "busy" } },
+      });
+      for (const event of assistantTurnEvents({
+        sessionId: "ses_parent_plugin_wake",
+        text: "Parent consumed the background result.",
+      })) {
+        openCode.emitEvent(event);
+      }
+
+      await vi.waitFor(() => {
+        expect(turnEventSignatures(events)).toEqual([
+          ["turn_started", "opencode-turn-0"],
+          ["timeline", "opencode-turn-0"],
+          ["timeline", "opencode-turn-0"],
+          ["turn_completed", "opencode-turn-0"],
+        ]);
+      });
+      expect(events).toContainEqual(
+        expect.objectContaining({
+          type: "timeline",
+          item: expect.objectContaining({
+            type: "assistant_message",
+            text: "Parent consumed the background result.",
+          }),
+        }),
+      );
+    } finally {
+      await parent.close();
+    }
+  });
+
+  test("does not mistake OpenCode session metadata for an autonomous turn", async () => {
+    const { parent, openCode } = await createParentSession("ses_parent_metadata");
+    const events: AgentStreamEvent[] = [];
+    const streamDrained = createTestDeferred<void>();
+    parent.subscribe((event) => {
+      events.push(event);
+      if (event.type === "provider_subagent") {
+        streamDrained.resolve();
+      }
+    });
+
+    try {
+      openCode.emitEvent({
+        type: "session.created",
+        properties: { info: { id: "ses_parent_metadata" } },
+      });
+      openCode.emitEvent({
+        type: "session.idle",
+        properties: { sessionID: "ses_parent_metadata" },
+      });
+      for (const event of assistantTurnEvents({
+        sessionId: "ses_parent_metadata",
+        text: "Autonomous response.",
+      })) {
+        openCode.emitEvent(event);
+      }
+      openCode.emitEvent({
+        type: "session.created",
+        properties: {
+          info: {
+            id: "ses_child_after_parent_metadata",
+            parentID: "ses_parent_metadata",
+            title: "Stream drain marker",
+            directory: "/workspace/repo",
+          },
+        },
+      });
+
+      await streamDrained.promise;
+      expect(
+        turnEventSignatures(events.filter((event) => event.type !== "provider_subagent")),
+      ).toEqual([]);
+    } finally {
+      await parent.close();
+    }
+  });
+
+  test("keeps an autonomous turn active until OpenCode reaches its terminal event", async () => {
+    const { parent, openCode } = await createParentSession("ses_parent_active_wake");
+    const events: AgentStreamEvent[] = [];
+    parent.subscribe((event) => events.push(event));
+
+    try {
+      openCode.emitEvent(
+        userMessageEvents({
+          sessionId: "ses_parent_active_wake",
+          messageId: "msg_autonomous_wake",
+          text: "Autonomous wake",
+        })[0],
+      );
+      await vi.waitFor(() => {
+        expect(events).toEqual([
+          { type: "turn_started", provider: "opencode", turnId: "opencode-turn-0" },
+        ]);
+      });
+
+      await expect(parent.startTurn("Continue from Paseo")).rejects.toThrow(
+        "A foreground turn is already active",
+      );
+      expect(openCode.calls.sessionAbort).toEqual([]);
+      expect(openCode.calls.sessionPromptAsync).toEqual([]);
+    } finally {
+      await parent.close();
+    }
+  });
+  test("does not adopt late output from an interrupted Paseo turn", async () => {
+    const { parent, openCode } = await createParentSession("ses_parent_interrupted");
+    openCode.sessionPromptAsyncEvents = [];
+    const events: AgentStreamEvent[] = [];
+    const streamDrained = createTestDeferred<void>();
+    parent.subscribe((event) => {
+      events.push(event);
+      if (event.type === "provider_subagent") {
+        streamDrained.resolve();
+      }
+    });
+
+    try {
+      await parent.startTurn("Start from Paseo");
+      await parent.interrupt();
+
+      for (const event of userMessageEvents({
+        sessionId: "ses_parent_interrupted",
+        messageId: "msg_delayed_interrupted_user",
+        text: "Delayed interrupted prompt",
+      })) {
+        openCode.emitEvent(event);
+      }
+      for (const event of assistantTurnEvents({
+        sessionId: "ses_parent_interrupted",
+        text: "Late interrupted response.",
+      })) {
+        openCode.emitEvent(event);
+      }
+      openCode.emitEvent({
+        type: "session.created",
+        properties: {
+          info: {
+            id: "ses_child_after_interrupted_output",
+            parentID: "ses_parent_interrupted",
+            title: "Stream drain marker",
+            directory: "/workspace/repo",
+          },
+        },
+      });
+
+      await streamDrained.promise;
+      expect(events.filter((event) => event.type !== "provider_subagent")).toEqual([
+        { type: "turn_started", provider: "opencode", turnId: "opencode-turn-0" },
+        {
+          type: "turn_canceled",
+          provider: "opencode",
+          reason: "interrupted",
+          turnId: "opencode-turn-0",
+        },
+      ]);
+    } finally {
+      await parent.close();
+    }
+  });
+
+  test("synthesizes an autonomous turn for adopted child permissions", async () => {
     const { child, childClient, parent } = await createAdoptedChildSession();
     const completed = createTestDeferred<void>();
     const events: AgentStreamEvent[] = [];
@@ -2617,6 +2886,13 @@ describe("OpenCode provider subagent contract", () => {
         }),
       );
     });
+    expect(events.some((event) => event.type === "turn_started")).toBe(false);
+    expect(
+      events.find(
+        (event) =>
+          event.type === "permission_requested" && event.request.id === "perm_provider_child",
+      ),
+    ).not.toHaveProperty("turnId");
     expect(
       events.filter(
         (event) =>
@@ -3446,31 +3722,3 @@ function waitForAbort(signal: AbortSignal): Promise<void> {
     signal.addEventListener("abort", () => resolve(), { once: true });
   });
 }
-
-function abortableOpenCodeStream(signal: AbortSignal): AsyncIterable<OpenCodeEvent> {
-  return {
-    [Symbol.asyncIterator]: () => {
-      let emittedConnected = false;
-      return {
-        next: () => {
-          if (!emittedConnected) {
-            emittedConnected = true;
-            return Promise.resolve({
-              done: false,
-              value: { type: "server.connected", properties: {} } as OpenCodeEvent,
-            });
-          }
-          return new Promise<IteratorResult<OpenCodeEvent>>((resolve) => {
-            if (signal.aborted) {
-              resolve({ done: true, value: undefined });
-              return;
-            }
-            signal.addEventListener("abort", () => resolve({ done: true, value: undefined }), {
-              once: true,
-            });
-          });
-        },
-      };
-    },
-  };
-}
diff --git a/packages/server/src/server/agent/providers/opencode-agent.ts b/packages/server/src/server/agent/providers/opencode-agent.ts
index 0eeca0e7f..954896b6a 100644
--- a/packages/server/src/server/agent/providers/opencode-agent.ts
+++ b/packages/server/src/server/agent/providers/opencode-agent.ts
@@ -2756,6 +2756,11 @@ function createDeferred<T>(): Deferred<T> {
   return { promise, resolve, reject };
 }
 
+type OpenCodeTurnState =
+  | { status: "idle" }
+  | { status: "running"; turnId: string }
+  | { status: "stopping"; idle: Deferred<void> };
+
 function unwrapOpenCodeGlobalEvent(event: unknown): OpenCodeEvent | null {
   const record = readOpenCodeRecord(event);
   if (!record) {
@@ -2791,14 +2796,6 @@ function getOpenCodeEventSessionId(event: OpenCodeEvent): string | null {
   );
 }
 
-function isOpenCodeUserMessageEvent(event: OpenCodeEvent, sessionId: string): boolean {
-  return (
-    event.type === "message.updated" &&
-    event.properties.info.sessionID === sessionId &&
-    event.properties.info.role === "user"
-  );
-}
-
 function isOpenCodeTerminalEvent(event: OpenCodeEvent, sessionId: string): boolean {
   if (event.type === "session.idle" || event.type === "session.error") {
     return event.properties.sessionID === sessionId;
@@ -2893,7 +2890,6 @@ class OpenCodeAgentSession implements AgentSession {
   private autoAcceptEnabled = false;
   private pendingPermissions = new Map<string, AgentPermissionRequest>();
   private abortController: AbortController | null = null;
-  private pendingAbortPromise: Promise<void> | null = null;
   private accumulatedUsage: AgentUsage = {};
   private sessionTotalCostUsd: number | undefined;
   private mcpConfigured = false;
@@ -2915,8 +2911,7 @@ class OpenCodeAgentSession implements AgentSession {
   private availableModesCache: AgentMode[] | null = null;
   private readonly subscribers = new Set<(event: AgentStreamEvent) => void>();
   private nextTurnOrdinal = 0;
-  private activeForegroundTurnId: string | null = null;
-  private activeForegroundTurnSource: "paseo" | "external" | null = null;
+  private turnState: OpenCodeTurnState = { status: "idle" };
   private readonly runningToolCalls = new Map<string, ToolCallTimelineItem>();
   private subAgentsByCallId = new Map<string, OpenCodeSubAgentActivityState>();
   private subAgentCallIdByChildSessionId = new Map<string, string>();
@@ -2932,7 +2927,6 @@ class OpenCodeAgentSession implements AgentSession {
   private eventStreamAbortController: AbortController | null = null;
   private eventStreamReady: Deferred<void> | null = null;
   private eventStreamTask: Promise<void> | null = null;
-  private suppressTerminalUntilNextUserMessage = false;
   private closed = false;
   private readonly persistSession: boolean;
   private deletedFromProvider = false;
@@ -2967,6 +2961,10 @@ class OpenCodeAgentSession implements AgentSession {
     return this.sessionId;
   }
 
+  private get activeForegroundTurnId(): string | null {
+    return this.turnState.status === "running" ? this.turnState.turnId : null;
+  }
+
   get features(): AgentFeature[] {
     return [buildOpenCodeAutoAcceptFeature(this.config)];
   }
@@ -3008,29 +3006,24 @@ class OpenCodeAgentSession implements AgentSession {
   }
 
   async interrupt(): Promise<void> {
-    let turnId = this.activeForegroundTurnId;
-    const turnAbortController = this.abortController;
-    turnAbortController?.abort();
+    const turnId = this.activeForegroundTurnId;
+    this.abortController?.abort();
+    if (turnId) {
+      this.beginStoppingTurn(turnId);
+    }
     // COMPAT(opencodeSlowAbort): OpenCode 1.14.42+ blocks session.abort until
     // the running tool actually stops, which can be tens of seconds for
     // long-running tools. Cap the wait so the user-visible cancel lands
     // quickly while still giving OpenCode a chance to confirm the abort
     // cleanly. Drop the timeout once upstream returns abort acknowledgement
     // before tool teardown.
-    const abortPromise = this.beginSessionAbort(turnId, "interrupt");
+    const abortPromise = this.abortSession(turnId, "interrupt");
     await withTimeout(abortPromise, 2_000, "OpenCode session.abort").catch((error) => {
       this.logger.warn(
         { err: error, sessionId: this.sessionId, turnId },
         "OpenCode session.abort exceeded the cancel cap; proceeding with local cancel",
       );
     });
-    if (turnId) {
-      this.suppressTerminalUntilNextUserMessage = true;
-      this.finishForegroundTurn(
-        { type: "turn_canceled", provider: "opencode", reason: "interrupted" },
-        turnId,
-      );
-    }
   }
 
   async revertBoth(input: { messageId: string }): Promise<void> {
@@ -3042,8 +3035,8 @@ class OpenCodeAgentSession implements AgentSession {
     });
   }
 
-  private beginSessionAbort(turnId: string | null, reason: string): Promise<void> {
-    const abortPromise = this.client.session
+  private abortSession(turnId: string | null, reason: string): Promise<void> {
+    return this.client.session
       .abort({
         sessionID: this.sessionId,
         directory: this.config.cwd,
@@ -3055,49 +3048,77 @@ class OpenCodeAgentSession implements AgentSession {
           "OpenCode session.abort rejected",
         );
       });
-    const trackedAbortPromise = abortPromise.finally(() => {
-      if (this.pendingAbortPromise === trackedAbortPromise) {
-        this.pendingAbortPromise = null;
-      }
-    });
-    this.pendingAbortPromise = trackedAbortPromise;
-    return trackedAbortPromise;
   }
 
-  private async awaitPendingAbortBeforeStartingTurn(): Promise<void> {
-    const pendingAbortPromise = this.pendingAbortPromise;
-    if (!pendingAbortPromise) {
+  private async waitUntilProviderIdle(): Promise<void> {
+    if (this.turnState.status !== "stopping") {
       return;
     }
 
+    const stopping = this.turnState;
+    // OpenCode creates prompts before joining its single session runner. Sending
+    // while that runner is stopping can strand the new prompt behind the old
+    // run, so only provider-confirmed idle makes the session reusable.
     await withTimeout(
-      pendingAbortPromise,
+      this.observeProviderStopBoundary(stopping),
       OPENCODE_PENDING_ABORT_START_TIMEOUT_MS,
-      "OpenCode pending session.abort",
-    ).catch((error) => {
-      this.logger.warn(
-        { err: error, sessionId: this.sessionId },
-        "OpenCode session.abort was still pending before starting the next turn",
-      );
-    });
+      "OpenCode previous turn to stop",
+    );
+  }
+
+  private async observeProviderStopBoundary(
+    stopping: Extract<OpenCodeTurnState, { status: "stopping" }>,
+  ): Promise<void> {
+    while (this.turnState === stopping) {
+      void this.abortSession(null, "turn_start_boundary");
+      const eventStreamTask = this.eventStreamTask;
+      const boundary = await (eventStreamTask
+        ? Promise.race([
+            stopping.idle.promise.then(() => "idle" as const),
+            eventStreamTask.then(
+              () => "stream_ended" as const,
+              () => "stream_ended" as const,
+            ),
+          ])
+        : Promise.resolve("stream_ended" as const));
+      if (boundary === "idle") {
+        return;
+      }
+
+      await this.ensureEventStreamReady();
+      const response = await this.client.session.status({ directory: this.config.cwd });
+      if (response.error) {
+        throw new Error(
+          `Failed to confirm OpenCode session status: ${toDiagnosticErrorMessage(response.error)}`,
+        );
+      }
+      const statuses = readOpenCodeRecord(response.data);
+      if (!statuses) {
+        throw new Error("OpenCode returned an invalid session status response");
+      }
+      const status = readOpenCodeRecord(statuses[this.sessionId]);
+      const statusType = readNonEmptyString(status?.type);
+      if (!status || statusType === "idle") {
+        this.finishStoppingTurn();
+        return;
+      }
+      if (statusType !== "busy" && statusType !== "retry") {
+        throw new Error(`OpenCode returned an unknown session status '${statusType ?? "missing"}'`);
+      }
+    }
   }
 
   async startTurn(
     prompt: AgentPromptInput,
     options?: AgentRunOptions,
   ): Promise<{ turnId: string }> {
-    if (this.activeForegroundTurnId) {
-      if (this.activeForegroundTurnSource === "external") {
-        // A direct Paseo prompt owns the foreground; close the adopted child run first.
-        this.finishForegroundTurn(
-          { type: "turn_completed", provider: "opencode", usage: undefined },
-          this.activeForegroundTurnId,
-        );
-      } else {
-        throw new Error("A foreground turn is already active");
-      }
+    if (this.turnState.status === "running") {
+      throw new Error("A foreground turn is already active");
+    }
+    await this.waitUntilProviderIdle();
+    if (this.turnState.status !== "idle") {
+      throw new Error("OpenCode is still stopping the previous turn");
     }
-    await this.awaitPendingAbortBeforeStartingTurn();
 
     this.runningToolCalls.clear();
     this.subAgentsByCallId.clear();
@@ -3127,8 +3148,7 @@ class OpenCodeAgentSession implements AgentSession {
     }
 
     const turnId = this.createTurnId();
-    this.activeForegroundTurnId = turnId;
-    this.activeForegroundTurnSource = "paseo";
+    this.turnState = { status: "running", turnId };
     this.notifySubscribers({ type: "turn_started", provider: "opencode" }, turnId);
 
     const slashCommand = await this.resolveSlashCommandInvocation(prompt);
@@ -3555,6 +3575,20 @@ class OpenCodeAgentSession implements AgentSession {
     if (!event) {
       return;
     }
+    if (
+      this.turnState.status === "stopping" &&
+      getOpenCodeEventSessionId(event) === this.sessionId
+    ) {
+      if (isOpenCodeTerminalEvent(event, this.sessionId)) {
+        this.finishStoppingTurn();
+      }
+      this.traceOpenCode("provider.opencode.event.skip", {
+        n: eventCount,
+        reason: "turn_stopping",
+        type: event.type,
+      });
+      return;
+    }
     const translated = await this.translateEvent(event);
     const foregroundEvents: AgentStreamEvent[] = [];
     for (const translatedEvent of translated) {
@@ -3564,8 +3598,8 @@ class OpenCodeAgentSession implements AgentSession {
         foregroundEvents.push(translatedEvent);
       }
     }
-    if (!turnId && this.shouldStartExternalDrivenTurn(event, foregroundEvents)) {
-      turnId = this.startExternalDrivenTurn();
+    if (!turnId && this.shouldStartAutonomousTurn(event, foregroundEvents)) {
+      turnId = this.startAutonomousTurn();
     }
     if (!turnId) {
       this.emitBackgroundPermissionRequests(foregroundEvents);
@@ -3576,18 +3610,6 @@ class OpenCodeAgentSession implements AgentSession {
       });
       return;
     }
-    if (this.suppressTerminalUntilNextUserMessage) {
-      if (isOpenCodeUserMessageEvent(event, this.sessionId)) {
-        this.suppressTerminalUntilNextUserMessage = false;
-      } else if (isOpenCodeTerminalEvent(event, this.sessionId)) {
-        this.traceOpenCode("provider.opencode.event.skip", {
-          n: eventCount,
-          reason: "stale_interrupt_terminal",
-          type: event.type,
-        });
-        return;
-      }
-    }
     this.traceOpenCode("provider.opencode.parsed_event", {
       turnId,
       n: eventCount,
@@ -3625,30 +3647,39 @@ class OpenCodeAgentSession implements AgentSession {
     }
   }
 
-  private shouldStartExternalDrivenTurn(
+  private shouldStartAutonomousTurn(
     event: OpenCodeEvent,
     foregroundEvents: readonly AgentStreamEvent[],
   ): boolean {
+    if (this.turnState.status !== "idle") {
+      return false;
+    }
+    if (getOpenCodeEventSessionId(event) !== this.sessionId) {
+      return false;
+    }
+    // OpenCode publishes the persisted user message before it marks the runner
+    // busy. That message is the earliest unambiguous boundary for a plugin-
+    // initiated parent turn; session metadata and assistant echoes are not.
+    if (event.type === "message.updated" && event.properties.info.role === "user") {
+      return true;
+    }
     if (!this.externallyDriven) {
       return false;
     }
-    if (this.activeForegroundTurnId) {
-      return false;
-    }
-    if (foregroundEvents.some((foregroundEvent) => !toTerminalTurnEvent(foregroundEvent))) {
+    if (
+      foregroundEvents.some(
+        (foregroundEvent) =>
+          foregroundEvent.type !== "thread_started" && !toTerminalTurnEvent(foregroundEvent),
+      )
+    ) {
       return true;
     }
-    return (
-      event.type === "session.status" &&
-      event.properties.sessionID === this.sessionId &&
-      event.properties.status.type === "busy"
-    );
+    return event.type === "session.status" && event.properties.status.type === "busy";
   }
 
-  private startExternalDrivenTurn(): string {
+  private startAutonomousTurn(): string {
     const turnId = this.createTurnId();
-    this.activeForegroundTurnId = turnId;
-    this.activeForegroundTurnSource = "external";
+    this.turnState = { status: "running", turnId };
     this.runningToolCalls.clear();
     this.subAgentsByCallId.clear();
     this.subAgentCallIdByChildSessionId.clear();
@@ -3680,12 +3711,36 @@ class OpenCodeAgentSession implements AgentSession {
     }
     this.pendingUserMessageText = null;
     this.pendingClientMessageId = null;
-    this.activeForegroundTurnId = null;
-    this.activeForegroundTurnSource = null;
+    this.turnState = { status: "idle" };
     this.abortController = null;
     this.notifySubscribers(event, turnId);
   }
 
+  private beginStoppingTurn(turnId: string): void {
+    if (this.turnState.status !== "running" || this.turnState.turnId !== turnId) {
+      return;
+    }
+    this.synthesizeInterruptedToolCalls(turnId);
+    this.pendingUserMessageText = null;
+    this.pendingClientMessageId = null;
+    this.abortController = null;
+    this.turnState = { status: "stopping", idle: createDeferred<void>() };
+    this.notifySubscribers(
+      { type: "turn_canceled", provider: "opencode", reason: "interrupted" },
+      turnId,
+    );
+  }
+
+  private finishStoppingTurn(): void {
+    if (this.turnState.status !== "stopping") {
+      return;
+    }
+    const stopping = this.turnState;
+    resetOpenCodeTurnTrackingState(this.createTranslationState());
+    this.turnState = { status: "idle" };
+    stopping.idle.resolve();
+  }
+
   private trackToolCall(item: ToolCallTimelineItem): void {
     if (item.status === "running") {
       this.runningToolCalls.set(item.callId, item);
@@ -3932,7 +3987,10 @@ class OpenCodeAgentSession implements AgentSession {
         logger: this.logger,
       });
       await this.deleteProviderSessionIfEphemeral();
-      this.activeForegroundTurnId = null;
+      if (this.turnState.status === "stopping") {
+        this.turnState.idle.resolve();
+      }
+      this.turnState = { status: "idle" };
     } finally {
       await this.releaseServer?.();
       this.releaseServer = null;
diff --git a/packages/server/src/server/agent/providers/opencode/test-utils/test-opencode-harness.ts b/packages/server/src/server/agent/providers/opencode/test-utils/test-opencode-harness.ts
index 3c3ac4dc7..b59399279 100644
--- a/packages/server/src/server/agent/providers/opencode/test-utils/test-opencode-harness.ts
+++ b/packages/server/src/server/agent/providers/opencode/test-utils/test-opencode-harness.ts
@@ -89,6 +89,7 @@ export class TestOpenCodeClient {
     sessionGet: [] as unknown[],
     sessionMessages: [] as unknown[],
     sessionPromptAsync: [] as unknown[],
+    sessionStatus: [] as unknown[],
     sessionSummarize: [] as unknown[],
     sessionUpdate: [] as unknown[],
   };
@@ -102,9 +103,13 @@ export class TestOpenCodeClient {
   permissionReplyResponse: OpenCodeResponse = {};
   providerListResponse: OpenCodeResponse = { data: { connected: [], all: [] } };
   providerListImplementation: (() => Promise<OpenCodeResponse>) | null = null;
+  globalEventImplementation:
+    | ((options: unknown) => Promise<{ stream: AsyncIterable<unknown> }>)
+    | null = null;
   questionRejectResponse: OpenCodeResponse = {};
   questionReplyResponse: OpenCodeResponse = {};
   sessionAbortResponse: OpenCodeResponse = {};
+  sessionAbortImplementation: ((parameters: unknown) => Promise<OpenCodeResponse>) | null = null;
   sessionCommandError: unknown = null;
   sessionCommandEvents: unknown[] = [idleEvent()];
   sessionCommandResponse: OpenCodeResponse = {};
@@ -118,6 +123,7 @@ export class TestOpenCodeClient {
   sessionMessagesResponse: OpenCodeResponse = { data: [] };
   sessionPromptAsyncEvents: unknown[] = [idleEvent()];
   sessionPromptAsyncResponse: OpenCodeResponse = {};
+  sessionStatusResponse: OpenCodeResponse = { data: {} };
   sessionSummarizeEvents: unknown[] = [idleEvent()];
   sessionSummarizeResponse: OpenCodeResponse = { data: {} };
   sessionUpdateResponse: OpenCodeResponse = {};
@@ -162,6 +168,9 @@ export class TestOpenCodeClient {
       global: {
         event: async (options: unknown) => {
           this.calls.globalEvent.push(options);
+          if (this.globalEventImplementation) {
+            return await this.globalEventImplementation(options);
+          }
           const signal = (options as { signal?: AbortSignal }).signal;
           return {
             stream: signal ? stopEventStreamOnAbort(this.eventStream, signal) : this.eventStream,
@@ -205,7 +214,9 @@ export class TestOpenCodeClient {
       session: {
         abort: async (parameters: unknown) => {
           this.calls.sessionAbort.push(parameters);
-          return this.sessionAbortResponse;
+          return this.sessionAbortImplementation
+            ? await this.sessionAbortImplementation(parameters)
+            : this.sessionAbortResponse;
         },
         command: async (parameters: unknown) => {
           this.calls.sessionCommand.push(parameters);
@@ -247,6 +258,10 @@ export class TestOpenCodeClient {
           }
           return this.sessionPromptAsyncResponse;
         },
+        status: async (parameters: unknown) => {
+          this.calls.sessionStatus.push(parameters);
+          return this.sessionStatusResponse;
+        },
         summarize: async (parameters: unknown) => {
           this.calls.sessionSummarize.push(parameters);
           for (const event of this.sessionSummarizeEvents) {