diff --git a/src/gateway/server-bridge.ts b/src/gateway/server-bridge.ts
index 6f676d26d..55f7f1f22 100644
--- a/src/gateway/server-bridge.ts
+++ b/src/gateway/server-bridge.ts
@@ -24,6 +24,7 @@ import { buildConfigSchema } from "../config/schema.js";
 import {
   loadSessionStore,
   mergeSessionEntry,
+  resolveAgentMainSessionKey,
   resolveMainSessionKeyFromConfig,
   type SessionEntry,
   saveSessionStore,
@@ -35,7 +36,10 @@ import {
 } from "../infra/voicewake.js";
 import { clearCommandLane } from "../process/command-queue.js";
 import { normalizeProviderId } from "../providers/plugins/index.js";
-import { normalizeMainKey } from "../routing/session-key.js";
+import {
+  normalizeMainKey,
+  resolveAgentIdFromSessionKey,
+} from "../routing/session-key.js";
 import { defaultRuntime } from "../runtime.js";
 import {
   abortChatRunById,
@@ -918,8 +922,14 @@ export function createBridgeHandlers(ctx: BridgeHandlersContext) {
               clientRunId,
             });
 
+            // Normalize short main key alias to canonical form before store write
+            const agentId = resolveAgentIdFromSessionKey(p.sessionKey);
+            const mainSessionKey = resolveAgentMainSessionKey({ cfg, agentId });
+            const rawMainKey = normalizeMainKey(cfg.session?.mainKey);
+            const storeKey =
+              p.sessionKey === rawMainKey ? mainSessionKey : p.sessionKey;
             if (store) {
-              store[p.sessionKey] = sessionEntry;
+              store[storeKey] = sessionEntry;
               if (storePath) {
                 await saveSessionStore(storePath, store);
               }
@@ -1032,12 +1042,18 @@ export function createBridgeHandlers(ctx: BridgeHandlersContext) {
         if (text.length > 20_000) return;
         const sessionKeyRaw =
           typeof obj.sessionKey === "string" ? obj.sessionKey.trim() : "";
-        const mainKey = normalizeMainKey(loadConfig().session?.mainKey);
-        const sessionKey = sessionKeyRaw.length > 0 ? sessionKeyRaw : mainKey;
+        const cfg = loadConfig();
+        const rawMainKey = normalizeMainKey(cfg.session?.mainKey);
+        const sessionKey = sessionKeyRaw.length > 0 ? sessionKeyRaw : rawMainKey;
         const { storePath, store, entry } = loadSessionEntry(sessionKey);
+        // Normalize short main key alias to canonical form before store write
+        const agentId = resolveAgentIdFromSessionKey(sessionKey);
+        const mainSessionKey = resolveAgentMainSessionKey({ cfg, agentId });
+        const storeKey =
+          sessionKey === rawMainKey ? mainSessionKey : sessionKey;
         const now = Date.now();
         const sessionId = entry?.sessionId ?? randomUUID();
-        store[sessionKey] = {
+        store[storeKey] = {
           sessionId,
           updatedAt: now,
           thinkingLevel: entry?.thinkingLevel,
@@ -1112,9 +1128,19 @@ export function createBridgeHandlers(ctx: BridgeHandlersContext) {
         const sessionKey =
           sessionKeyRaw.length > 0 ? sessionKeyRaw : `node-${nodeId}`;
         const { storePath, store, entry } = loadSessionEntry(sessionKey);
+        // Normalize short main key alias to canonical form before store write
+        const nodeCfg = loadConfig();
+        const nodeAgentId = resolveAgentIdFromSessionKey(sessionKey);
+        const nodeMainSessionKey = resolveAgentMainSessionKey({
+          cfg: nodeCfg,
+          agentId: nodeAgentId,
+        });
+        const nodeRawMainKey = normalizeMainKey(nodeCfg.session?.mainKey);
+        const nodeStoreKey =
+          sessionKey === nodeRawMainKey ? nodeMainSessionKey : sessionKey;
         const now = Date.now();
         const sessionId = entry?.sessionId ?? randomUUID();
-        store[sessionKey] = {
+        store[nodeStoreKey] = {
           sessionId,
           updatedAt: now,
           thinkingLevel: entry?.thinkingLevel,
diff --git a/src/gateway/server-methods/agent.ts b/src/gateway/server-methods/agent.ts
index 386755492..ce4e64b5f 100644
--- a/src/gateway/server-methods/agent.ts
+++ b/src/gateway/server-methods/agent.ts
@@ -189,12 +189,6 @@ export const agentHandlers: GatewayRequestHandlers = {
         );
         return;
       }
-      if (store) {
-        store[requestedSessionKey] = nextEntry;
-        if (storePath) {
-          await saveSessionStore(storePath, store);
-        }
-      }
       resolvedSessionId = sessionId;
       const agentId = resolveAgentIdFromSessionKey(requestedSessionKey);
       const mainSessionKey = resolveAgentMainSessionKey({
@@ -202,6 +196,15 @@ export const agentHandlers: GatewayRequestHandlers = {
         agentId,
       });
       const rawMainKey = normalizeMainKey(cfg.session?.mainKey);
+      // Normalize short main key alias to canonical form before store write
+      const storeKey =
+        requestedSessionKey === rawMainKey ? mainSessionKey : requestedSessionKey;
+      if (store) {
+        store[storeKey] = nextEntry;
+        if (storePath) {
+          await saveSessionStore(storePath, store);
+        }
+      }
       if (
         requestedSessionKey === mainSessionKey ||
         requestedSessionKey === rawMainKey
diff --git a/src/gateway/server-methods/chat.ts b/src/gateway/server-methods/chat.ts
index ac9647182..3da182034 100644
--- a/src/gateway/server-methods/chat.ts
+++ b/src/gateway/server-methods/chat.ts
@@ -3,7 +3,15 @@ import { randomUUID } from "node:crypto";
 import { resolveThinkingDefault } from "../../agents/model-selection.js";
 import { resolveAgentTimeoutMs } from "../../agents/timeout.js";
 import { agentCommand } from "../../commands/agent.js";
-import { mergeSessionEntry, saveSessionStore } from "../../config/sessions.js";
+import {
+  mergeSessionEntry,
+  resolveAgentMainSessionKey,
+  saveSessionStore,
+} from "../../config/sessions.js";
+import {
+  normalizeMainKey,
+  resolveAgentIdFromSessionKey,
+} from "../../routing/session-key.js";
 import { registerAgentRunContext } from "../../infra/agent-events.js";
 import { defaultRuntime } from "../../runtime.js";
 import { resolveSendPolicy } from "../../sessions/send-policy.js";
@@ -306,8 +314,14 @@ export const chatHandlers: GatewayRequestHandlers = {
         clientRunId,
       });
 
+      // Normalize short main key alias to canonical form before store write
+      const agentId = resolveAgentIdFromSessionKey(p.sessionKey);
+      const mainSessionKey = resolveAgentMainSessionKey({ cfg, agentId });
+      const rawMainKey = normalizeMainKey(cfg.session?.mainKey);
+      const storeKey =
+        p.sessionKey === rawMainKey ? mainSessionKey : p.sessionKey;
       if (store) {
-        store[p.sessionKey] = sessionEntry;
+        store[storeKey] = sessionEntry;
         if (storePath) {
           await saveSessionStore(storePath, store);
         }
diff --git a/src/gateway/session-utils.ts b/src/gateway/session-utils.ts
index 9ddc90b8d..aacd004f0 100644
--- a/src/gateway/session-utils.ts
+++ b/src/gateway/session-utils.ts
@@ -15,6 +15,7 @@ import {
   buildGroupDisplayName,
   loadSessionStore,
   resolveAgentIdFromSessionKey,
+  resolveAgentMainSessionKey,
   resolveSessionTranscriptPath,
   resolveStorePath,
   type SessionEntry,
@@ -172,7 +173,16 @@ export function loadSessionEntry(sessionKey: string) {
   const store = loadSessionStore(storePath);
   const parsed = parseAgentSessionKey(sessionKey);
   const legacyKey = parsed?.rest;
-  const entry = store[sessionKey] ?? (legacyKey ? store[legacyKey] : undefined);
+  // Also try the canonical key if sessionKey is the short mainKey alias
+  const rawMainKey = normalizeMainKey(sessionCfg?.mainKey);
+  const canonicalKey =
+    sessionKey === rawMainKey
+      ? resolveAgentMainSessionKey({ cfg, agentId })
+      : undefined;
+  const entry =
+    store[sessionKey] ??
+    (legacyKey ? store[legacyKey] : undefined) ??
+    (canonicalKey ? store[canonicalKey] : undefined);
   return { cfg, storePath, store, entry };
 }