fix: tolerate revoked Slack channel visibility during discovery

Co-Authored-By: Paperclip <noreply@paperclip.ing>

packages/shared/src/slack-tools.ts

@@ -145,7 +145,7 @@ export const SLACK_TOOLS = [
     "assistant.search.context",
     ["search:read.public", "search:read.files"],
     "read",
-    "Search authorized channels by text, author and time. Reports native search or bounded history scan and its coverage. Never claim a partial scan is exhaustive.",
+    "Search authorized channel history by text, author and time. Pass channels as an array of channel IDs, query as plain text, and limit from 1 to 20 (matches per channel, not messages scanned). Reports bounded scan coverage; never claim it is exhaustive.",
     {
       channels: z.array(channel).min(1).max(10),
       query: text,

server/src/__tests__/chat-channels.integration.test.ts

@@ -4002,6 +4002,19 @@ describeEmbeddedPostgres("chat channel control-plane integration", () => {
     const read = await executeSlackTool(db, binding, "slack_history", { channel: "COTHER" }, fetched as typeof fetch);
     expect(read).toMatchObject({ sourceTrust: "untrusted", nextCursor: "older", hasMore: true });
     expect(JSON.stringify(read)).toContain("UUNLINKED");
+    const directoryFetch = vi.fn(async (input: RequestInfo | URL, init?: RequestInit) => {
+      const method = String(input).split("/").at(-1);
+      const args = Object.fromEntries(new URLSearchParams(String(init?.body ?? "")));
+      if (method === "conversations.list") return Response.json({ ok: true, channels: [{ id: "CGONE", is_member: true }, { id: "COTHER", is_member: true }], response_metadata: { next_cursor: "directory-next" } });
+      if (method === "conversations.info" && args.channel === "CGONE") return Response.json({ ok: false, error: "channel_not_found" });
+      return fetched(input, init);
+    });
+    await expect(executeSlackTool(db, binding, "slack_channels", {}, directoryFetch as typeof fetch)).resolves.toMatchObject({ channels: [{ id: "COTHER" }], nextCursor: "directory-next" });
+    await expect(executeSlackTool(db, binding, "slack_search", { channels: ["COTHER"], query: "ship Tuesday", limit: 10 }, fetched as typeof fetch)).resolves.toMatchObject({
+      mode: "bounded_history", exhaustive: false,
+      matches: [{ user: "UUNLINKED", ts: "7000.1" }],
+      inspected: [{ channel: "COTHER", count: 1, nextCursor: "older", hasMore: true }],
+    });
     await expect(executeSlackTool(db, binding, "slack_history", { channel: "GPRIVATE" }, fetched as typeof fetch)).rejects.toThrow("in a DM");
     vi.stubEnv("PAPERCLIP_TOOL_ACTION_SIGNING_SECRET", "slack-tools-integration-signing-secret");
     onTestFinished(() => vi.unstubAllEnvs());

server/src/services/connectors/slack-access.test.ts

@@ -9,6 +9,7 @@ import { slackClient } from "./slack-client.js";
 import type { SlackTaskAuthority } from "./slack-authority.js";
 import type { Db } from "@paperclipai/db";
 import { SLACK_TOOLS } from "@paperclipai/shared";
+import { tooManyRequests, unprocessable } from "../../errors.js";
 const authority = {
   endpoint: {
     id: "endpoint",
@@ -48,6 +49,18 @@ const fakeDb = (rows: unknown[]) =>
     select: () => ({ from: () => ({ where: async () => rows }) }),
   }) as unknown as Db;
 describe("Slack access and publication boundaries", () => {
+  it("treats missing channels as access denials without hiding provider failures", async () => {
+    for (const code of ["slack_channel_not_found", "slack_not_in_channel"]) {
+      const api = apiFor({});
+      api.mockRejectedValue(unprocessable("Slack rejected the lookup", { code }));
+      await expect(authorizeSlackChannel(authority, api, "C1")).rejects.toMatchObject({ status: 403 });
+    }
+    for (const error of [tooManyRequests("Rate limited"), unprocessable("Missing scope", { code: "slack_missing_scope" })]) {
+      const api = apiFor({});
+      api.mockRejectedValue(error);
+      await expect(authorizeSlackChannel(authority, api, "C1")).rejects.toBe(error);
+    }
+  });
   it("reads a public shared channel without checking the enabled response destination", async () => {
     expect((await authorizeSlackChannel(authority, apiFor({}), "C1")).id).toBe(
       "C1",

server/src/services/connectors/slack-access.ts

@@ -1,6 +1,6 @@
 import { and, eq, sql } from "drizzle-orm";
 import { chatActions, chatEndpointResources, type Db } from "@paperclipai/db";
-import { forbidden, unprocessable } from "../../errors.js";
+import { HttpError, forbidden, unprocessable } from "../../errors.js";
 import type { SlackTaskAuthority } from "./slack-authority.js";
 import {
   nextCursor,
@@ -15,9 +15,21 @@ export async function authorizeSlackChannel(
   api: Api,
   channelId: string,
 ) {
-  const channel = object(
-    (await api("conversations.info", { channel: channelId })).channel,
-  );
+  let channel: SlackObject;
+  try {
+    channel = object(
+      (await api("conversations.info", { channel: channelId })).channel,
+    );
+  } catch (error) {
+    // Membership can disappear between listing and inspection. Slack also
+    // hides inaccessible conversations with channel_not_found. Treat only
+    // these definite access failures as denials; outages must still surface.
+    if (error instanceof HttpError && error.status === 422 &&
+      ["slack_channel_not_found", "slack_not_in_channel"].includes(String(object(error.details).code))) {
+      throw forbidden("This Slack channel is no longer accessible to the bot");
+    }
+    throw error;
+  }
   if (
     channel.id !== channelId ||
     (channel.is_member !== true && channel.is_im !== true)

skills/slack/SKILL.md

@@ -38,6 +38,13 @@ history scan is not workspace-wide search and does not automatically inspect
 thread replies. Fetch further history/thread pages when needed. Report omitted
 history, rate limits, missing scopes and unavailable Slack features accurately.
 
+For example, to search the assigned channel, call `slack_search` with
+`{"channels":["C012AB3CD"],"query":"launch decision","limit":10}`, substituting
+the supplied channel ID. `channels` is an array; `limit` is at most 20 matches,
+not the history page size. Do not add Slack search syntax to a channel ID or
+pass unsupported fields. A schema rejection means the arguments need correcting;
+it does not mean another Slack connection is needed.
+
 ## Collaboration and delivery
 
 Use Slack messages, uploads, reactions, pins, bookmarks, topics, canvases and lists