fix: canonicalize main session keys

src/gateway/protocol/schema/snapshot.ts

@@ -22,6 +22,16 @@ export const PresenceEntrySchema = Type.Object(
 
 export const HealthSnapshotSchema = Type.Any();
 
+export const SessionDefaultsSchema = Type.Object(
+  {
+    defaultAgentId: NonEmptyString,
+    mainKey: NonEmptyString,
+    mainSessionKey: NonEmptyString,
+    scope: Type.Optional(NonEmptyString),
+  },
+  { additionalProperties: false },
+);
+
 export const StateVersionSchema = Type.Object(
   {
     presence: Type.Integer({ minimum: 0 }),
@@ -38,6 +48,7 @@ export const SnapshotSchema = Type.Object(
     uptimeMs: Type.Integer({ minimum: 0 }),
     configPath: Type.Optional(NonEmptyString),
     stateDir: Type.Optional(NonEmptyString),
+    sessionDefaults: Type.Optional(SessionDefaultsSchema),
   },
   { additionalProperties: false },
 );

src/gateway/server/health-state.ts

@@ -1,5 +1,8 @@
+import { resolveDefaultAgentId } from "../../agents/agent-scope.js";
 import { getHealthSnapshot, type HealthSummary } from "../../commands/health.js";
-import { CONFIG_PATH_CLAWDBOT, STATE_DIR_CLAWDBOT } from "../../config/config.js";
+import { CONFIG_PATH_CLAWDBOT, STATE_DIR_CLAWDBOT, loadConfig } from "../../config/config.js";
+import { resolveMainSessionKey } from "../../config/sessions.js";
+import { normalizeMainKey } from "../../routing/session-key.js";
 import { listSystemPresence } from "../../infra/system-presence.js";
 import type { Snapshot } from "../protocol/index.js";
 
@@ -10,6 +13,11 @@ let healthRefresh: Promise<HealthSummary> | null = null;
 let broadcastHealthUpdate: ((snap: HealthSummary) => void) | null = null;
 
 export function buildGatewaySnapshot(): Snapshot {
+  const cfg = loadConfig();
+  const defaultAgentId = resolveDefaultAgentId(cfg);
+  const mainKey = normalizeMainKey(cfg.session?.mainKey);
+  const mainSessionKey = resolveMainSessionKey(cfg);
+  const scope = cfg.session?.scope ?? "per-sender";
   const presence = listSystemPresence();
   const uptimeMs = Math.round(process.uptime() * 1000);
   // Health is async; caller should await getHealthSnapshot and replace later if needed.
@@ -22,6 +30,12 @@ export function buildGatewaySnapshot(): Snapshot {
     // Surface resolved paths so UIs can display the true config location.
     configPath: CONFIG_PATH_CLAWDBOT,
     stateDir: STATE_DIR_CLAWDBOT,
+    sessionDefaults: {
+      defaultAgentId,
+      mainKey,
+      mainSessionKey,
+      scope,
+    },
   };
 }