diff --git a/src/renderer/src/api/agent.ts b/src/renderer/src/api/agent.ts
index e54ab88506..b84ccf1fa0 100644
--- a/src/renderer/src/api/agent.ts
+++ b/src/renderer/src/api/agent.ts
@@ -7,6 +7,7 @@ import {
   CreateAgentResponse,
   CreateAgentResponseSchema,
   CreateSessionForm,
+  CreateSessionMessageRequest,
   CreateSessionRequest,
   CreateSessionResponse,
   CreateSessionResponseSchema,
@@ -208,4 +209,14 @@ export class AgentApiClient {
       throw processError(error, 'Failed to update session.')
     }
   }
+
+  public async createMessage(agentId: string, sessionId: string, content: string): Promise<void> {
+    const url = this.getSessionMessagesPath(agentId, sessionId)
+    try {
+      const payload = { content } satisfies CreateSessionMessageRequest
+      await this.axios.post(url, payload)
+    } catch (error) {
+      throw processError(error, 'Failed to post message.')
+    }
+  }
 }
diff --git a/src/renderer/src/types/agent.ts b/src/renderer/src/types/agent.ts
index a5ead13d77..58e7e5e7cb 100644
--- a/src/renderer/src/types/agent.ts
+++ b/src/renderer/src/types/agent.ts
@@ -204,9 +204,7 @@ export const ListAgentSessionsResponseSchema = z.object({
 
 export type ListAgentSessionsResponse = z.infer<typeof ListAgentSessionsResponseSchema>
 
-export interface CreateSessionMessageRequest {
-  content: string
-}
+export type CreateSessionMessageRequest = z.infer<typeof CreateSessionMessageRequestSchema>
 
 export const CreateSessionResponseSchema = AgentSessionEntitySchema