Memory: __setDefaultMemory does not initialize titleGenerator, breaking generateTitle for global memory

[lzj960515]

Summary

When Memory is passed globally to VoltAgent (via the memory option) instead of directly to each Agent, the generateTitle configuration is silently ignored and conversation titles are never generated.

Root Cause

Agent constructor resolves memory and builds titleGenerator at construction time:

// agent.ts
const resolvedMemory = this.memoryConfigured
  ? options.memory
  : AgentRegistry.getInstance().getGlobalAgentMemory();

const titleGenerator = this.createConversationTitleGenerator(
  resolvedMemory instanceof Memory ? resolvedMemory : undefined,
);

this.memoryManager = new MemoryManager(this.id, resolvedMemory, {}, this.logger, titleGenerator);

When agents are instantiated as module-level singletons (common pattern), AgentRegistry.getGlobalAgentMemory() returns undefined because VoltAgent hasn't run yet. So titleGenerator is set to undefined.

Later, VoltAgent calls agent.__setDefaultMemory(memory), which only updates conversationMemory in MemoryManager — it does not re-initialize titleGenerator:

// MemoryManager.setMemory
setMemory(memory: Memory | false): void {
  if (memory instanceof Memory) {
    this.conversationMemory = memory; // titleGenerator is never updated
  }
}

Steps to Reproduce

// agents/assistant.ts — module-level singleton, no memory passed
export default new Agent({ name: "assistant", model: "...", tools });

// index.ts
const memory = new Memory({ storage: adapter, generateTitle: true });

new VoltAgent({
  agents: { assistant },
  memory, // passed globally
});

With this setup, generateTitle has no effect. All conversations receive the fallback title "Conversation".

Expected Behavior

__setDefaultMemory should also update (or lazily initialize) titleGenerator so that generateTitle works regardless of whether memory is passed globally or per-agent.

Workaround

Pass memory directly to each Agent constructor:

export function createAssistant(memory: Memory) {
  return new Agent({ name: "assistant", model: "...", tools, memory });
}

Environment

• @voltagent/core latest

[omeraplak]

Hi @lzj960515, thanks for the clear report and root-cause notes. I was able to reproduce this with a preconstructed agent using global memory on VoltAgent: the conversation title stayed on the fallback instead of using generateTitle.

I opened a fix in #1248. The change makes __setDefaultMemory initialize the title generator from the global memory when it is applied to the agent, and adds a regression test for the global-memory path. I also verified the repro from examples/base; after the fix the conversation title resolves to the generated title instead of the fallback.