fix(slack): treat null search arguments as omitted

packages/junior/src/chat/slack/tools/public-search.ts

@@ -338,7 +338,7 @@ function explicitSearchError(error: SlackActionError): string | undefined {
 }
 
 function normalizeContentTypes(
-  contentTypes: Array<(typeof CONTENT_TYPES)[number]> | undefined,
+  contentTypes: Array<(typeof CONTENT_TYPES)[number]> | null | undefined,
 ): Array<(typeof CONTENT_TYPES)[number]> {
   const selected = contentTypes?.length
     ? contentTypes
@@ -368,27 +368,41 @@ export function createSlackPublicSearchTool(actionToken?: SlackActionToken) {
         .array(z.enum(CONTENT_TYPES))
         .min(1)
         .max(4)
-        .describe("Content types to include. Defaults to messages.")
+        .nullable()
+        .describe("Content types to include. Omit or use null for messages.")
         .optional(),
-      after: optionalUnixTimestampParam("Unix timestamp lower bound."),
-      before: optionalUnixTimestampParam("Unix timestamp upper bound."),
+      after: optionalUnixTimestampParam(
+        "Unix timestamp lower bound.",
+      ).nullable(),
+      before: optionalUnixTimestampParam(
+        "Unix timestamp upper bound.",
+      ).nullable(),
       cursor: z
         .string()
         .min(1)
-        .describe("Cursor for the next result page.")
+        .nullable()
+        .describe(
+          "Cursor for the next result page. Omit or use null for the first page.",
+        )
         .optional(),
       limit: z.coerce
         .number()
         .int()
         .min(1)
         .max(20)
+        .nullable()
         .describe("Maximum results to return; Slack allows at most 20.")
         .optional(),
       sort: z
         .enum(["score", "timestamp"])
+        .nullable()
         .describe("Rank by relevance or timestamp.")
         .optional(),
-      sort_dir: z.enum(["asc", "desc"]).describe("Sort direction.").optional(),
+      sort_dir: z
+        .enum(["asc", "desc"])
+        .nullable()
+        .describe("Sort direction.")
+        .optional(),
     }),
     outputSchema: publicSearchOutputSchema,
     execute: async ({

packages/junior/tests/integration/slack-public-search.test.ts

@@ -292,6 +292,36 @@ describe("Slack public search", () => {
     expect(params).not.toHaveProperty("before");
   });
 
+  it("treats null optional arguments as omitted", async () => {
+    queueSlackApiResponse("assistant.search.context", {
+      body: { ok: true, results: { messages: [] } },
+    });
+    const tool = createSlackPublicSearchTool(actionToken);
+    const input = tool.prepareArguments({
+      query: "company announcement",
+      content_types: null,
+      after: null,
+      before: null,
+      cursor: null,
+      limit: null,
+      sort: null,
+      sort_dir: null,
+    });
+
+    await executeTool(tool, input);
+
+    expect(
+      getCapturedSlackApiCalls("assistant.search.context")[0]?.params,
+    ).toEqual({
+      action_token: "action-123",
+      query: "company announcement",
+      channel_types: ["public_channel"],
+      content_types: ["messages"],
+      include_bots: "true",
+      limit: "10",
+    });
+  });
+
   it("reports a missing public-search scope explicitly", async () => {
     queueSlackApiError("assistant.search.context", {
       error: "missing_scope",