feat(web): inspect bounded Subagent owner details

README.md

@@ -582,6 +582,8 @@ openpi web /path/to/repo      # 指定初始工作区
 
 Web 可以在选择工作区之前预选可用模型。选择仅保留在当前页面，创建会话后确认模型生效再发送第一条消息；模型不可用时会提示并阻止发送，不会自动换成默认模型。打开已有会话时使用该会话的模型。
 
+Web 的 Subagent 活动条可打开当前 Web Session 的只读详情：状态和完成/中断结果来自原有 Subagent manager，模型、轮次、近期工具与输出只以有界文本展示。该面板不控制或接管子代理，不代表完整子 Session transcript；终端中启动的另一 Pi Session 不会自动出现在当前 Web Session 中。
+
 Pi 当前只原生分派 `install`、`remove`、`update`、`list`、`config` 和 `auth` 等固定子命令，package 不能注册新的顶层子命令。因此 Web 入口是独立 CLI 的 `openpi web`，不是会被 Pi 当成初始 Prompt 的 `pi open`。Web 进程仍沿用 Pi 的 Provider、模型、凭据、Settings、Trust、Session 格式和 extension 资源加载，不引入第二套 Provider 或 Session 存储。
 
 ### 命令速查

extensions/shared/web-observer-registry.ts

@@ -77,7 +77,37 @@ export interface WebBackgroundTerminalDetail {
   readonly truncated: boolean;
 }
 
-export type WebCapabilityDetail = WebBackgroundTerminalDetail;
+export interface WebSubagentDetail {
+  readonly kind: "subagents";
+  readonly id: string;
+  readonly title: string;
+  readonly cwd: string;
+  readonly origin: "model" | "btw";
+  readonly status: WebSubagentActivity["status"];
+  readonly outcome?: WebSubagentActivity["outcome"];
+  readonly createdAt: number;
+  readonly settledAt?: number;
+  readonly modelLabel?: string;
+  readonly turns: number;
+  readonly transcriptItems: number;
+  readonly latestOutput: {
+    readonly text: string;
+    readonly omittedBytes: number;
+  };
+  readonly errorText?: string;
+  readonly liveTools: readonly {
+    readonly name: string;
+    readonly done: boolean;
+    readonly isError?: boolean;
+    readonly outputPreview?: string;
+  }[];
+  readonly toolsOmitted: number;
+  readonly truncated: boolean;
+}
+
+export type WebCapabilityDetail =
+  | WebBackgroundTerminalDetail
+  | WebSubagentDetail;
 
 export type WebCapabilityDetailReceipt =
   | { readonly status: "found"; readonly detail: WebCapabilityDetail }
@@ -148,6 +178,91 @@ function boundedUtf8Tail(value: string, maxBytes: number): BoundedUtf8Text {
   };
 }
 
+export function projectSubagentDetail(source: {
+  readonly id: string;
+  readonly title: string;
+  readonly cwd: string;
+  readonly origin: WebSubagentDetail["origin"];
+  readonly status: WebSubagentDetail["status"];
+  readonly outcome?: WebSubagentDetail["outcome"];
+  readonly createdAt: number;
+  readonly settledAt?: number;
+  readonly meta: { readonly modelLabel?: string };
+  readonly turns: number;
+  readonly transcript: readonly unknown[];
+  readonly finalText: string;
+  readonly liveAssistant?: { readonly text: string };
+  readonly errorText?: string;
+  readonly liveTools: readonly {
+    readonly name: string;
+    readonly done?: boolean;
+    readonly isError?: boolean;
+    readonly outputPreview?: string;
+  }[];
+}): WebSubagentDetail {
+  const title = boundedActivityText(source.title);
+  const cwd = boundedUtf8Tail(source.cwd, 2 * 1024);
+  const model = source.meta.modelLabel
+    ? boundedActivityText(source.meta.modelLabel)
+    : undefined;
+  const latestOutput =
+    source.status === "running"
+      ? (source.liveAssistant?.text.trim() ?? "")
+      : source.finalText;
+  const output = boundedUtf8Tail(latestOutput, 8 * 1024);
+  const error = source.errorText
+    ? boundedUtf8Tail(source.errorText, 2 * 1024)
+    : undefined;
+  const selectedTools = source.liveTools.slice(-8);
+  const tools = selectedTools.map((tool) => {
+    const name = boundedActivityText(tool.name);
+    const preview = tool.outputPreview
+      ? boundedUtf8Tail(tool.outputPreview, 1024)
+      : undefined;
+    return {
+      item: {
+        name: name.value,
+        done: tool.done === true,
+        ...(tool.isError !== undefined ? { isError: tool.isError } : {}),
+        ...(preview ? { outputPreview: preview.value } : {}),
+      },
+      truncated: name.truncated || preview?.truncated === true,
+    };
+  });
+  const toolsOmitted = source.liveTools.length - selectedTools.length;
+  return {
+    kind: "subagents",
+    id: source.id,
+    title: title.value,
+    cwd: cwd.value,
+    origin: source.origin,
+    status: source.status,
+    ...(source.outcome ? { outcome: source.outcome } : {}),
+    createdAt: source.createdAt,
+    ...(source.settledAt !== undefined ? { settledAt: source.settledAt } : {}),
+    ...(model ? { modelLabel: model.value } : {}),
+    turns: source.turns,
+    transcriptItems: source.transcript.length,
+    latestOutput: {
+      text: output.value,
+      omittedBytes: output.truncated
+        ? new TextEncoder().encode(latestOutput).byteLength - output.bytes
+        : 0,
+    },
+    ...(error ? { errorText: error.value } : {}),
+    liveTools: tools.map(({ item }) => item),
+    toolsOmitted,
+    truncated:
+      title.truncated ||
+      cwd.truncated ||
+      model?.truncated === true ||
+      output.truncated ||
+      error?.truncated === true ||
+      toolsOmitted > 0 ||
+      tools.some(({ truncated }) => truncated),
+  };
+}
+
 function projectTerminalOutput(
   source: {
     readonly modelSafeText: string;

extensions/subagents/index.ts

@@ -83,6 +83,7 @@ import {
 } from "../shared/tool-surface.ts";
 import {
   projectSubagentCapability,
+  projectSubagentDetail,
   registerWebCapability,
 } from "../shared/web-observer-registry.ts";
 import {
@@ -575,6 +576,10 @@ export default function (
             ? registerWebCapability(scope, {
                 kind: "subagents",
                 snapshot: () => projectSubagentCapability(manager.view.list()),
+                detail: (id) => {
+                  const agent = manager.view.get(id);
+                  return agent ? projectSubagentDetail(agent) : undefined;
+                },
                 subscribe: (listener) => manager.view.subscribe(listener),
               })
             : undefined;

tests/web/app-render.spec.ts

@@ -450,6 +450,28 @@ it("keeps background terminal activity and omission receipts visible", () => {
   expect(screen.getByText("+3")).toBeTruthy();
 });
 
+it("opens Subagent activity by exact id without treating it as a terminal", () => {
+  const snapshot = activeSnapshot();
+  snapshot.runtime.capabilities = {
+    subagents: {
+      items: [
+        {
+          id: "child-1",
+          title: "Investigate",
+          status: "running",
+          createdAt: 1,
+        },
+      ],
+      omitted: 0,
+      truncated: false,
+    },
+  };
+  const inspect = vi.fn();
+  render(createElement(ActivityBar, { snapshot, onInspectSubagent: inspect }));
+  fireEvent.click(screen.getByRole("button", { name: /Investigate/u }));
+  expect(inspect).toHaveBeenCalledExactlyOnceWith("child-1");
+});
+
 it("resolves canonical system theme changes and explicit overrides", () => {
   const initial = webStore.getState().snapshot;
   const media = new EventTarget();

tests/web/inspection-panel.spec.ts

@@ -181,6 +181,56 @@ it("rejects another Session's same-id terminal and renders output as plain text"
   ).toBeTruthy();
 });
 
+it("shows exact Subagent outcome and bounded text without granting control", async () => {
+  const detail = {
+    kind: "subagents",
+    id: "child-1",
+    title: "Investigate",
+    cwd: "/ws",
+    origin: "model",
+    status: "error",
+    outcome: "interrupted",
+    createdAt: 1,
+    settledAt: 2,
+    modelLabel: "provider/model",
+    turns: 2,
+    transcriptItems: 12,
+    latestOutput: {
+      text: '<img src="https://external.example/x" onerror="alert(1)">',
+      omittedBytes: 20,
+    },
+    errorText: "Stopped after cancellation",
+    liveTools: [{ name: "read", done: true, outputPreview: "partial result" }],
+    toolsOmitted: 3,
+    truncated: true,
+  };
+  const fetcher = vi
+    .fn()
+    .mockResolvedValueOnce(reply({ sessionId: "wrong", detail }))
+    .mockResolvedValueOnce(reply({ sessionId: "session-a", detail }));
+  vi.stubGlobal("fetch", fetcher);
+  const view = show({ ...target, subagentId: "child-1" });
+  expect(
+    await screen.findByText("The active session changed. Reopen this panel."),
+  ).toBeTruthy();
+  expect(screen.queryByText("Stopped after cancellation")).toBeNull();
+  fireEvent.click(screen.getByRole("button", { name: "Refresh status" }));
+  expect(await screen.findByText("Stopped after cancellation")).toBeTruthy();
+  expect(screen.getByText("Error · Interrupted")).toBeTruthy();
+  expect(screen.getByText("2 turns · 12 records")).toBeTruthy();
+  expect(screen.getByText("3 earlier tools omitted.")).toBeTruthy();
+  expect(
+    screen.getByText("20 bytes omitted from this output view."),
+  ).toBeTruthy();
+  expect(screen.getByText(detail.latestOutput.text)).toBeTruthy();
+  expect(view.container.querySelector(".terminal-evidence img")).toBeNull();
+  expect(fetcher).toHaveBeenCalledWith(
+    "/api/capabilities/detail?kind=subagents&id=child-1&sessionId=session-a",
+    expect.objectContaining({ signal: expect.any(AbortSignal) }),
+  );
+  expect(fetcher.mock.calls[0]?.[1]).not.toHaveProperty("method");
+});
+
 function thinkingFetcher(thinking: unknown) {
   return vi.fn(async (url: string) => {
     if (url.startsWith("/api/thinking")) return reply(thinking);

tests/web/observer-registry.test.ts

@@ -10,6 +10,7 @@ import {
   projectBackgroundTerminalCapability,
   projectBackgroundTerminalDetail,
   projectSubagentCapability,
+  projectSubagentDetail,
   projectWorkflowCapability,
   registerWebCapability,
   subscribeWebCapabilities,
@@ -332,3 +333,79 @@ test("detail lookup is Session-scoped, exact, and fail-closed", () => {
     unregister();
   }
 });
+
+test("Subagent detail bounds owner evidence and retains exact outcome", () => {
+  const detail = projectSubagentDetail({
+    id: "child-1",
+    title: "Investigate",
+    cwd: "/repo",
+    origin: "model",
+    status: "error",
+    outcome: "interrupted",
+    createdAt: 1,
+    settledAt: 2,
+    meta: { modelLabel: "provider/model" },
+    turns: 3,
+    transcript: Array.from({ length: 100 }, () => ({})),
+    finalText: "🙂".repeat(6000),
+    errorText: "failure".repeat(1000),
+    liveTools: Array.from({ length: 12 }, (_, index) => ({
+      name: `tool-${index}`,
+      done: index < 10,
+      outputPreview: "x".repeat(3000),
+    })),
+  });
+  assert.equal(detail.outcome, "interrupted");
+  assert.equal(detail.transcriptItems, 100);
+  assert.equal(detail.liveTools.length, 8);
+  assert.equal(detail.toolsOmitted, 4);
+  assert.ok(Buffer.byteLength(detail.latestOutput.text) <= 8 * 1024);
+  assert.ok(detail.latestOutput.omittedBytes > 0);
+  assert.ok(Buffer.byteLength(detail.errorText ?? "") <= 2 * 1024);
+  assert.ok(
+    detail.liveTools.every(
+      (tool) => Buffer.byteLength(tool.outputPreview ?? "") <= 1024,
+    ),
+  );
+  assert.equal(detail.truncated, true);
+
+  const scope = sessionScope();
+  const unregister = registerWebCapability(scope, {
+    kind: "subagents",
+    snapshot: () => ({ items: [], omitted: 0, truncated: false }),
+    detail: (id) => (id === detail.id ? detail : undefined),
+  });
+  try {
+    assert.deepEqual(webCapabilityDetail(scope, "subagents", "child-1"), {
+      status: "found",
+      detail,
+    });
+    assert.deepEqual(webCapabilityDetail(scope, "subagents", "child-2"), {
+      status: "missing",
+    });
+    assert.deepEqual(
+      webCapabilityDetail(sessionScope(), "subagents", "child-1"),
+      { status: "unavailable" },
+    );
+  } finally {
+    unregister();
+  }
+});
+
+test("a restarted running Subagent does not present the previous run's final text as live output", () => {
+  const detail = projectSubagentDetail({
+    id: "child-2",
+    title: "Continue",
+    cwd: "/repo",
+    origin: "model",
+    status: "running",
+    createdAt: 1,
+    meta: {},
+    turns: 1,
+    transcript: [],
+    finalText: "previous run",
+    liveTools: [],
+  });
+  assert.equal(detail.latestOutput.text, "");
+  assert.equal(detail.truncated, false);
+});