diff --git a/packages/host/apiproxy/src/api-proxy.ts b/packages/host/apiproxy/src/api-proxy.ts
index 72fff0cdf0..8ee0a02175 100644
--- a/packages/host/apiproxy/src/api-proxy.ts
+++ b/packages/host/apiproxy/src/api-proxy.ts
@@ -1773,7 +1773,13 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
             })
           }
         }
-        return ok(request, { sessionId })
+        // Echo the RESOLVED composition so a client can label the session it
+        // just created without waiting for the next list refresh — the create
+        // is the commit point that knows it (a caller that named none gets
+        // the default the header recorded).
+        const created = ctx.agents.get(sessionId)
+        const createdPreset = created?.session.header.agentPreset
+        return ok(request, { sessionId, ...createdPreset === undefined ? {} : { agentPreset: createdPreset } })
       },
 
       async history(request) {
diff --git a/packages/host/apiproxy/src/api/events.schema.ts b/packages/host/apiproxy/src/api/events.schema.ts
index 13ead7d08d..b432880810 100644
--- a/packages/host/apiproxy/src/api/events.schema.ts
+++ b/packages/host/apiproxy/src/api/events.schema.ts
@@ -73,6 +73,7 @@ export const hostFrameSchema = z.discriminatedUnion('type', [
     parentSessionId: sessionIdSchema.optional(),
     origin: z.literal('subagent').optional(),
     cwd: z.string().optional(),
+    agentPreset: z.string().optional(),
   }),
   z.object({ type: z.literal('host/session-removed'), sessionId: sessionIdSchema }),
   z.object({ type: z.literal('host/session-status'), sessionId: sessionIdSchema, running: z.boolean() }),
diff --git a/packages/host/apiproxy/src/api/events.ts b/packages/host/apiproxy/src/api/events.ts
index 7fc54f6f01..555e08a9a2 100644
--- a/packages/host/apiproxy/src/api/events.ts
+++ b/packages/host/apiproxy/src/api/events.ts
@@ -116,6 +116,7 @@ export type HostFrame =
     parentSessionId?: SessionId
     origin?: 'subagent'
     cwd?: string
+    agentPreset?: string
   }
   | { type: 'host/session-removed'; sessionId: SessionId }
   | { type: 'host/session-status'; sessionId: SessionId; running: boolean }
diff --git a/packages/host/apiproxy/src/api/sessions.schema.ts b/packages/host/apiproxy/src/api/sessions.schema.ts
index 7e2ead7c2b..b20dc66579 100644
--- a/packages/host/apiproxy/src/api/sessions.schema.ts
+++ b/packages/host/apiproxy/src/api/sessions.schema.ts
@@ -109,6 +109,7 @@ export const sessionCreateRequestSchema = z.object({
 /** session.create response value. */
 export const sessionCreateValueSchema = z.object({
   sessionId: sessionIdSchema,
+  agentPreset: z.string().optional(),
 }) satisfies z.ZodType<Wire<ResponseValue<'session.create'>>>
 
 /** session.rename request payload (raw title; host-side normalization decides acceptance). */
diff --git a/packages/host/apiproxy/src/api/sessions.ts b/packages/host/apiproxy/src/api/sessions.ts
index 2fa9a65916..c2966b7cb3 100644
--- a/packages/host/apiproxy/src/api/sessions.ts
+++ b/packages/host/apiproxy/src/api/sessions.ts
@@ -217,7 +217,7 @@ export interface SessionsApi {
    * cannot be mounted fails with `agent-preset-invalid`.
    */
   create(request: RpcRequest<{ workspaceId?: WorkspaceId; cwd?: string; sessionId?: SessionId; agentPreset?: string }>):
-  Promise<RpcResponse<{ sessionId: SessionId }>>
+  Promise<RpcResponse<{ sessionId: SessionId; agentPreset?: string }>>
 
   /**
    * Reads a window of history events; page boundaries align to append-origin message