From 640bbe06414cf9778a54a1cf2409b9872d7aa0ef Mon Sep 17 00:00:00 2001
From: Max Korp <maxkorp@8bytealchemy.com>
Date: Fri, 12 Sep 2025 15:21:00 -0700
Subject: [PATCH] Allow passing a messagesMapper prop when instantiating mastra
 agent

For example, this allows you to take an array slice to provide only a single message (most recent) to the agent when using memory
---
 typescript-sdk/integrations/mastra/src/mastra.ts | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/typescript-sdk/integrations/mastra/src/mastra.ts b/typescript-sdk/integrations/mastra/src/mastra.ts
index f8310767b..291ee1876 100644
--- a/typescript-sdk/integrations/mastra/src/mastra.ts
+++ b/typescript-sdk/integrations/mastra/src/mastra.ts
@@ -1,6 +1,7 @@
 import type {
   AgentConfig,
   BaseEvent,
+  Message,
   RunAgentInput,
   RunFinishedEvent,
   RunStartedEvent,
@@ -34,6 +35,7 @@ import {
 
 export interface MastraAgentConfig extends AgentConfig {
   agent: LocalMastraAgent | RemoteMastraAgent;
+  messagesMapper?: (messages: Message[]) => Message[];
   resourceId?: string;
   runtimeContext?: RuntimeContext;
 }
@@ -51,12 +53,14 @@ export class MastraAgent extends AbstractAgent {
   agent: LocalMastraAgent | RemoteMastraAgent;
   resourceId?: string;
   runtimeContext?: RuntimeContext;
+  messagesMapper?: (messages: Message[]) => Message[];
 
-  constructor({ agent, resourceId, runtimeContext, ...rest }: MastraAgentConfig) {
+  constructor({ agent, resourceId, runtimeContext, messagesMapper, ...rest }: MastraAgentConfig) {
     super(rest);
     this.agent = agent;
     this.resourceId = resourceId;
     this.runtimeContext = runtimeContext ?? new RuntimeContext();
+    this.messagesMapper = messagesMapper;
   }
 
   protected run(input: RunAgentInput): Observable<BaseEvent> {
@@ -249,7 +253,7 @@ export class MastraAgent extends AbstractAgent {
       {} as Record<string, any>,
     );
     const resourceId = this.resourceId ?? threadId;
-    const convertedMessages = convertAGUIMessagesToMastra(messages);
+    const convertedMessages = convertAGUIMessagesToMastra(this.messagesMapper ? this.messagesMapper(messages) : messages);
     this.runtimeContext?.set('ag-ui', { context: inputContext });
     const runtimeContext = this.runtimeContext;