feat(channels): ship production thread and feed UX (#3481)

Author: k11kirky

.claude/skills/quill-code/SKILL.md

@@ -0,0 +1,93 @@
+---
+name: quill-code
+description: Edit the @posthog/quill design system locally and consume the change in this repo (posthog-code) before it is published to npm. Use when changing quill components/primitives/tokens, when a quill change must be tested inside the Code app, or when the user mentions quill, the design system, the .local-quill tarball, or the @posthog/quill pnpm override.
+---
+
+# quill-code
+
+`@posthog/quill` is **not** in this repo. It is a published catalog dependency whose
+source lives in the main PostHog monorepo at `../posthog/packages/quill`. To test an
+unpublished quill change inside this repo (posthog-code), you build quill, pack it to a
+tarball, and point a pnpm `overrides` entry at that tarball. This is a **temporary
+local-dev** state — revert before merging (see below).
+
+## Quill layout (where to edit)
+
+`../posthog/packages/quill` is the **workspace** (`@posthog/quill-workspace`). It
+contains sub-packages, each a layer of the design system:
+
+- `packages/primitives/src` — base components (Card, Badge, Button, Progress, …)
+- `packages/components/src` — composed components (DataTable, DateTimePicker, Metric)
+- `packages/blocks/src` — **product-level blocks** (e.g. `ExperimentCard`). Add the
+  file here and export it from `packages/blocks/src/index.ts`.
+- `packages/quill/src` — the **aggregate** that re-exports all layers as `@posthog/quill`.
+
+A new export in any sub-package flows to `@posthog/quill` automatically on build.
+
+## The loop (every quill change)
+
+1. Edit/add the component in the right sub-package (above) and export it from that
+   package's `src/index.ts`.
+2. Re-sync into this repo manually — build → pack → point the override → reinstall:
+
+   ```bash
+   QUILL_DIR="${QUILL_DIR:-../posthog/packages/quill/packages/quill}"
+
+   # a. Build the WHOLE quill workspace (two levels up from the aggregate), so the
+   #    sub-packages rebuild BEFORE the aggregate bundles them.
+   ( cd "$QUILL_DIR/../.." && pnpm build )
+
+   # b. Pack into .local-quill/ under a UNIQUE filename. pnpm pins a tarball by
+   #    integrity, so a stable name caches stale across re-syncs — drop old local
+   #    tarballs first, then rename the packed file to a unique local name.
+   rm -f .local-quill/posthog-quill-local-*.tgz
+   ( cd "$QUILL_DIR" && npm pack --pack-destination "$(git rev-parse --show-toplevel)/.local-quill" )
+   mv .local-quill/posthog-quill-[0-9]*.tgz ".local-quill/posthog-quill-local-$(git rev-parse --short HEAD)-$$.tgz"
+
+   # c. Point the override at the new tarball, then reinstall.
+   #    Edit pnpm-workspace.yaml so overrides['@posthog/quill'] = file:./.local-quill/<new file>
+   pnpm install
+   ```
+
+   > Building only the aggregate (`packages/quill/packages/quill`) re-bundles the
+   > sub-packages' **stale** `dist/`, so edits to primitives/components/blocks are
+   > silently dropped. Always build at the workspace root.
+3. Verify in the Code app (`pnpm dev`, or the `test-electron-app` skill). Repeat from 1.
+
+After every quill edit you **must** re-run the sync — the app consumes the tarball, not
+the quill source, so unsynced edits are invisible here.
+
+If quill lives elsewhere, set `QUILL_DIR=/abs/path/to/posthog/packages/quill/packages/quill`.
+
+## Why a tarball, not `link:`
+
+`link:` symlinks into the mono's `node_modules` and drags in its **React 18** types,
+colliding with this repo's **React 19** (dual-React → broken typecheck +
+invalid-hook-call at runtime). The tarball is copied into this repo's store and deduped
+against React 19. The filename is **content-hashed** because pnpm pins a tarball by
+integrity, so a stable filename gets cached stale across re-syncs.
+
+## The override (what the script rewrites)
+
+In `pnpm-workspace.yaml`, under `overrides:`:
+
+```yaml
+'@posthog/quill': file:./.local-quill/posthog-quill-local-<hash>.tgz
+```
+
+There is also a permanent pin you should leave alone:
+
+```yaml
+'@posthog/quill>@base-ui/react': ^1.3.0   # quill ships a broken catalog: dep; do not remove
+```
+
+## Reverting (before merge)
+
+The override is local-dev only. Once the quill change is published to npm:
+
+1. Bump the catalog version in `pnpm-workspace.yaml` (`'@posthog/quill': 0.3.0-beta.x`)
+   to the published version.
+2. Restore the override line to point back at the catalog, or remove the `file:` override.
+3. `pnpm install`.
+
+Do not commit a `file:./.local-quill/...` override or the `.local-quill/` tarballs.

apps/code/src/renderer/desktop-contributions.ts

@@ -1,6 +1,7 @@
 import { agentChatCoreModule } from "@posthog/core/agent-chat/agentChat.module";
 import { autoresearchCoreModule } from "@posthog/core/autoresearch/autoresearch.module";
 import { billingCoreModule } from "@posthog/core/billing/billing.module";
+import { taskThreadCoreModule } from "@posthog/core/canvas/taskThread.module";
 import { inboxCoreModule } from "@posthog/core/inbox/inbox.module";
 import { githubConnectModule } from "@posthog/core/integrations/githubConnect.module";
 import { localMcpCoreModule } from "@posthog/core/local-mcp/local-mcp.module";
@@ -37,6 +38,7 @@ export function registerDesktopContributions(): void {
     autoresearchCoreModule,
     billingUiModule,
     billingCoreModule,
+    taskThreadCoreModule,
     browserTabsUiModule,
     cloneUiModule,
     connectivityUiModule,

apps/web/src/web-container.ts

@@ -1,5 +1,6 @@
 import "reflect-metadata";
 import { TypedContainer } from "@inversifyjs/strongly-typed";
+import { taskThreadCoreModule } from "@posthog/core/canvas/taskThread.module";
 import { setRootContainer } from "@posthog/di/container";
 import { ROOT_LOGGER, type RootLogger } from "@posthog/di/logger";
 import {
@@ -96,4 +97,6 @@ container.bind(MCP_SANDBOX_PROXY_URL).toConstantValue(() => {
   return sandboxProxyUrl;
 });
 
+container.load(taskThreadCoreModule);
+
 setRootContainer(container);

packages/core/src/canvas/channelFeed.test.ts

@@ -0,0 +1,28 @@
+import { describe, expect, it } from "vitest";
+import { taskFeedRunStatus } from "./channelFeed";
+
+describe("taskFeedRunStatus", () => {
+  it.each(["queued", "in_progress"] as const)(
+    "preserves a cloud %s status even when local session activity has settled",
+    (status) => {
+      expect(
+        taskFeedRunStatus({
+          status,
+          environment: "cloud",
+        }),
+      ).toBe(status);
+    },
+  );
+
+  it("hides an unreliable non-terminal local status", () => {
+    expect(
+      taskFeedRunStatus({ status: "queued", environment: "local" }),
+    ).toBeNull();
+  });
+
+  it("keeps a terminal local status", () => {
+    expect(
+      taskFeedRunStatus({ status: "completed", environment: "local" }),
+    ).toBe("completed");
+  });
+});

packages/core/src/canvas/channelFeed.ts

@@ -0,0 +1,23 @@
+import type { TaskRunStatus } from "@posthog/shared/domain-types";
+import { isTerminalStatus } from "@posthog/shared/domain-types";
+
+const PERMANENT_CHANNEL_FEED_FAILURES = new Set([401, 403, 404]);
+
+export function shouldPollChannelFeed(error: unknown): boolean {
+  if (!error || typeof error !== "object" || !("status" in error)) return true;
+  const status = (error as { status?: unknown }).status;
+  return (
+    typeof status !== "number" || !PERMANENT_CHANNEL_FEED_FAILURES.has(status)
+  );
+}
+
+export function taskFeedRunStatus({
+  status,
+  environment,
+}: {
+  status: TaskRunStatus | null | undefined;
+  environment: string | null | undefined;
+}): TaskRunStatus | null {
+  if (!status) return null;
+  return environment === "cloud" || isTerminalStatus(status) ? status : null;
+}

packages/core/src/canvas/taskThread.module.ts

@@ -0,0 +1,7 @@
+import { ContainerModule } from "inversify";
+import { TASK_THREAD_SERVICE, TaskThreadService } from "./taskThreadService";
+
+export const taskThreadCoreModule = new ContainerModule(({ bind }) => {
+  bind(TaskThreadService).toSelf().inSingletonScope();
+  bind(TASK_THREAD_SERVICE).toService(TaskThreadService);
+});

packages/core/src/canvas/taskThreadService.test.ts

@@ -0,0 +1,66 @@
+import type { PostHogAPIClient } from "@posthog/api-client/posthog-client";
+import type { TaskThreadMessage } from "@posthog/shared/domain-types";
+import { describe, expect, it, vi } from "vitest";
+import { TaskThreadService } from "./taskThreadService";
+
+function message(
+  overrides: Partial<TaskThreadMessage> = {},
+): TaskThreadMessage {
+  return {
+    id: "message-id",
+    task: "task-id",
+    content: "@agent investigate this",
+    created_at: "2026-07-16T00:00:00Z",
+    ...overrides,
+  };
+}
+
+function client(overrides: Partial<PostHogAPIClient> = {}): PostHogAPIClient {
+  return overrides as PostHogAPIClient;
+}
+
+describe("TaskThreadService", () => {
+  it("creates a message before forwarding it to the agent", async () => {
+    const createTaskThreadMessage = vi.fn().mockResolvedValue(message());
+    const sendTaskThreadMessageToAgent = vi
+      .fn()
+      .mockResolvedValue(
+        message({ forwarded_to_agent_at: "2026-07-16T00:00:01Z" }),
+      );
+    const service = new TaskThreadService();
+
+    await service.postMessageToAgent(
+      client({ createTaskThreadMessage, sendTaskThreadMessageToAgent }),
+      "task-id",
+      "@agent investigate this",
+    );
+
+    expect(createTaskThreadMessage).toHaveBeenCalledWith(
+      "task-id",
+      "@agent investigate this",
+    );
+    expect(sendTaskThreadMessageToAgent).toHaveBeenCalledWith(
+      "task-id",
+      "message-id",
+    );
+    expect(createTaskThreadMessage.mock.invocationCallOrder[0]).toBeLessThan(
+      sendTaskThreadMessageToAgent.mock.invocationCallOrder[0],
+    );
+  });
+
+  it("returns the created message when forwarding fails", async () => {
+    const sendError = new Error("No active run");
+    const service = new TaskThreadService();
+
+    await expect(
+      service.postMessageToAgent(
+        client({
+          createTaskThreadMessage: vi.fn().mockResolvedValue(message()),
+          sendTaskThreadMessageToAgent: vi.fn().mockRejectedValue(sendError),
+        }),
+        "task-id",
+        "@agent investigate this",
+      ),
+    ).resolves.toEqual({ message: message(), sendError });
+  });
+});

packages/core/src/canvas/taskThreadService.ts

@@ -0,0 +1,31 @@
+import type { PostHogAPIClient } from "@posthog/api-client/posthog-client";
+import type { TaskThreadMessage } from "@posthog/shared/domain-types";
+import { injectable } from "inversify";
+
+export const TASK_THREAD_SERVICE = Symbol.for(
+  "posthog.core.canvas.taskThreadService",
+);
+
+export interface PostMessageToAgentResult {
+  message: TaskThreadMessage;
+  sendError: unknown | null;
+}
+
+@injectable()
+export class TaskThreadService {
+  async postMessageToAgent(
+    client: PostHogAPIClient,
+    taskId: string,
+    content: string,
+  ): Promise<PostMessageToAgentResult> {
+    const message = await client.createTaskThreadMessage(taskId, content);
+    try {
+      return {
+        message: await client.sendTaskThreadMessageToAgent(taskId, message.id),
+        sendError: null,
+      };
+    } catch (sendError) {
+      return { message, sendError };
+    }
+  }
+}