diff --git a/src/agents/tools/gateway-tool.test.ts b/src/agents/tools/gateway-tool.test.ts
index 11e207c3376..81ac3b7649f 100644
--- a/src/agents/tools/gateway-tool.test.ts
+++ b/src/agents/tools/gateway-tool.test.ts
@@ -167,4 +167,53 @@ describe("createGatewayTool – live delivery context guard", () => {
     expect(sentinelPayload?.deliveryContext?.channel).toBe("discord");
     expect(sentinelPayload?.deliveryContext?.to).toBe("123456789");
   });
+
+  it("does not forward live RPC delivery context when a non-default agent passes sessionKey='main'", async () => {
+    // "main" resolves to "agent:main:main" (default agent), which differs from the
+    // current session "agent:shopping-claw:main". Live context must NOT be forwarded.
+    mocks.callGatewayTool.mockClear();
+    const tool = createGatewayTool({
+      agentSessionKey: "agent:shopping-claw:main",
+      agentChannel: "discord",
+      agentTo: "123456789",
+    });
+
+    await execTool(tool, {
+      action: "config.patch",
+      raw: '{"key":"value"}',
+      baseHash: "abc123",
+      sessionKey: "main", // targets default agent — different from current shopping-claw session
+      note: "cross-agent patch",
+    });
+
+    const forwardedParams = getCallArg<Record<string, unknown>>(mocks.callGatewayTool, 0, 2);
+    expect(forwardedParams?.deliveryContext).toBeUndefined();
+  });
+
+  it("does not forward live restart context when a non-default agent passes sessionKey='main'", async () => {
+    // "main" resolves to "agent:main:main" (default agent), which differs from the
+    // current session "agent:shopping-claw:main". Sentinel must not carry this session's thread.
+    mocks.writeRestartSentinel.mockClear();
+    mocks.extractDeliveryInfo.mockReturnValueOnce({
+      deliveryContext: { channel: "telegram", to: "+19995550001", accountId: undefined },
+      threadId: undefined,
+    });
+
+    const tool = createGatewayTool({
+      agentSessionKey: "agent:shopping-claw:main",
+      agentChannel: "discord",
+      agentTo: "123456789",
+    });
+
+    await execTool(tool, { action: "restart", sessionKey: "main" });
+
+    const sentinelPayload = getCallArg<{ deliveryContext?: { channel?: string; to?: string } }>(
+      mocks.writeRestartSentinel,
+      0,
+      0,
+    );
+    // Should fall back to extractDeliveryInfo() for the targeted session, not current session's live context
+    expect(sentinelPayload?.deliveryContext?.channel).toBe("telegram");
+    expect(sentinelPayload?.deliveryContext?.to).toBe("+19995550001");
+  });
 });
diff --git a/src/agents/tools/gateway-tool.ts b/src/agents/tools/gateway-tool.ts
index 09f24880cbf..27c89750764 100644
--- a/src/agents/tools/gateway-tool.ts
+++ b/src/agents/tools/gateway-tool.ts
@@ -116,9 +116,29 @@ export function createGatewayTool(opts?: {
         // session, the live context belongs to the wrong session and would
         // misroute the post-restart reply. Fall back to extractDeliveryInfo()
         // so the server uses the correct routing for the target session.
+        // Canonicalize both keys before comparing so that aliases like "main"
+        // and "agent:main:main" are treated as the same session. Without this,
+        // an operator passing sessionKey="main" would be incorrectly treated as
+        // targeting a different session, suppressing live deliveryContext and
+        // falling back to the stale session store. See #18612.
+        const ownKey = opts?.agentSessionKey?.trim() || undefined;
+        const agentId = resolveAgentIdFromSessionKey(ownKey);
+        // Canonicalize each key using its OWN agentId — not the current session's.
+        // If a non-default agent passes sessionKey="main", resolveAgentIdFromSessionKey
+        // returns DEFAULT_AGENT_ID ("main") so "main" → "agent:main:main". Using the
+        // current session's agentId instead would map "main" to the current agent's main
+        // session, falsely treating a cross-agent request as same-session. See #18612.
+        const canonicalizeOwn = (k: string) =>
+          canonicalizeMainSessionAlias({ cfg: opts?.config, agentId, sessionKey: k });
+        const canonicalizeTarget = (k: string) =>
+          canonicalizeMainSessionAlias({
+            cfg: opts?.config,
+            agentId: resolveAgentIdFromSessionKey(k),
+            sessionKey: k,
+          });
         const isTargetingOtherSession =
           explicitSessionKey != null &&
-          explicitSessionKey !== (opts?.agentSessionKey?.trim() || undefined);
+          canonicalizeTarget(explicitSessionKey) !== (ownKey ? canonicalizeOwn(ownKey) : undefined);
         // Only forward live context when both channel and to are present.
         // Forwarding a partial context (channel without to) causes the server
         // to write a sentinel without `to`, and scheduleRestartSentinelWake
@@ -228,12 +248,26 @@ export function createGatewayTool(opts?: {
             ? Math.floor(params.restartDelayMs)
             : undefined;
         // Only forward live context when the target session is this agent's
-        // own session. When an explicit sessionKey points to a different
-        // session, omit deliveryContext so the server falls back to
-        // extractDeliveryInfo(sessionKey) which uses that session's routing.
+        // own session. Canonicalize both keys before comparing so that aliases
+        // like "main" and "agent:main:main" are treated as the same session.
+        // When an explicit sessionKey points to a different session, omit
+        // deliveryContext so the server falls back to extractDeliveryInfo(sessionKey).
+        const rpcOwnKey = opts?.agentSessionKey?.trim() || undefined;
+        const rpcAgentId = resolveAgentIdFromSessionKey(rpcOwnKey);
+        // Same cross-agent alias fix as the restart path: derive agentId from each key
+        // independently so that "main" resolves to the default agent, not the current one.
+        const rpcCanonicalizeOwn = (k: string) =>
+          canonicalizeMainSessionAlias({ cfg: opts?.config, agentId: rpcAgentId, sessionKey: k });
+        const rpcCanonicalizeTarget = (k: string) =>
+          canonicalizeMainSessionAlias({
+            cfg: opts?.config,
+            agentId: resolveAgentIdFromSessionKey(k),
+            sessionKey: k,
+          });
         const isTargetingOtherSession =
           explicitSessionKey != null &&
-          explicitSessionKey !== (opts?.agentSessionKey?.trim() || undefined);
+          rpcCanonicalizeTarget(explicitSessionKey) !==
+            (rpcOwnKey ? rpcCanonicalizeOwn(rpcOwnKey) : undefined);
         const deliveryContext = isTargetingOtherSession ? undefined : liveDeliveryContextForRpc;
         return { sessionKey, note, restartDelayMs, deliveryContext };
       };