Address PR feedback

src/agents/tools/discord-actions-presence.test.ts

@@ -196,6 +196,12 @@ describe("handleDiscordPresenceAction", () => {
     );
   });
 
+  it("requires activityType when activityName is provided", async () => {
+    await expect(
+      handleDiscordPresenceAction("setPresence", { activityName: "My Game" }, presenceEnabled),
+    ).rejects.toThrow(/activityType is required/);
+  });
+
   it("rejects unknown presence actions", async () => {
     await expect(handleDiscordPresenceAction("unknownAction", {}, presenceEnabled)).rejects.toThrow(
       /Unknown presence action/,

src/agents/tools/discord-actions-presence.ts

@@ -55,7 +55,13 @@ export async function handleDiscordPresenceAction(
   const activities: Activity[] = [];
 
   if (activityTypeRaw || activityName) {
-    const typeNum = activityTypeRaw ? ACTIVITY_TYPE_MAP[activityTypeRaw.toLowerCase()] : 0;
+    if (!activityTypeRaw) {
+      throw new Error(
+        "activityType is required when activityName is provided. " +
+          `Valid types: ${Object.keys(ACTIVITY_TYPE_MAP).join(", ")}`,
+      );
+    }
+    const typeNum = ACTIVITY_TYPE_MAP[activityTypeRaw.toLowerCase()];
     if (typeNum === undefined) {
       throw new Error(
         `Invalid activityType "${activityTypeRaw}". Must be one of: ${Object.keys(ACTIVITY_TYPE_MAP).join(", ")}`,

src/discord/monitor/gateway-registry.test.ts

@@ -23,11 +23,12 @@ describe("gateway-registry", () => {
     expect(getGateway("account-b")).toBeUndefined();
   });
 
-  it("uses 'default' key when accountId is undefined", () => {
+  it("uses collision-safe key when accountId is undefined", () => {
     const gateway = fakeGateway();
     registerGateway(undefined, gateway);
     expect(getGateway(undefined)).toBe(gateway);
-    expect(getGateway("default")).toBe(gateway);
+    // "default" as a literal account ID must not collide with the sentinel key
+    expect(getGateway("default")).toBeUndefined();
   });
 
   it("unregisters a gateway", () => {

src/discord/monitor/gateway-registry.ts

@@ -8,8 +8,12 @@ import type { GatewayPlugin } from "@buape/carbon/gateway";
  */
 const gatewayRegistry = new Map<string, GatewayPlugin>();
 
+// Sentinel key for the default (unnamed) account. Uses a prefix that cannot
+// collide with user-configured account IDs.
+const DEFAULT_ACCOUNT_KEY = "\0__default__";
+
 function resolveAccountKey(accountId?: string): string {
-  return accountId ?? "default";
+  return accountId ?? DEFAULT_ACCOUNT_KEY;
 }
 
 /** Register a GatewayPlugin instance for an account. */