From b36bb8beef1e44f00fc62c1ee224ed51f7dc13db Mon Sep 17 00:00:00 2001
From: Charles Packer <packercharles@gmail.com>
Date: Thu, 29 Jan 2026 17:17:06 -0800
Subject: [PATCH] feat: enable memfs by default for newly created agents (#748)

Co-authored-by: Letta <noreply@letta.com>
---
 src/headless.ts |  8 +++++++-
 src/index.ts    | 10 ++++++++--
 2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/src/headless.ts b/src/headless.ts
index 27d7ce6..196a9fd 100644
--- a/src/headless.ts
+++ b/src/headless.ts
@@ -213,6 +213,7 @@ export async function handleHeadlessCommand(
 
   // Resolve agent (same logic as interactive mode)
   let agent: AgentState | null = null;
+  let isNewlyCreatedAgent = false;
   let specifiedAgentId = values.agent as string | undefined;
   let specifiedConversationId = values.conversation as string | undefined;
   const useDefaultConv = values.default as boolean | undefined;
@@ -450,6 +451,7 @@ export async function handleHeadlessCommand(
       stripMessages: true,
     });
     agent = result.agent;
+    isNewlyCreatedAgent = true;
   }
 
   // Priority 2: Try to use --agent specified ID
@@ -481,6 +483,7 @@ export async function handleHeadlessCommand(
     };
     const result = await createAgent(createOptions);
     agent = result.agent;
+    isNewlyCreatedAgent = true;
   }
 
   // Priority 4: Try to resume from project settings (.letta/settings.local.json)
@@ -589,11 +592,14 @@ export async function handleHeadlessCommand(
     }
   }
 
-  // Apply memfs flag if specified
+  // Apply memfs flag if specified, or enable by default for new agents
   if (memfsFlag) {
     settingsManager.setMemfsEnabled(agent.id, true);
   } else if (noMemfsFlag) {
     settingsManager.setMemfsEnabled(agent.id, false);
+  } else if (isNewlyCreatedAgent && !isSubagent) {
+    // Enable memfs by default for newly created agents (but not subagents)
+    settingsManager.setMemfsEnabled(agent.id, true);
   }
 
   // Sync filesystem-backed memory before creating conversations (only if memfs is enabled)
diff --git a/src/index.ts b/src/index.ts
index dde1093..720644e 100755
--- a/src/index.ts
+++ b/src/index.ts
@@ -1427,6 +1427,7 @@ async function main(): Promise<void> {
         const { getModelUpdateArgs } = await import("./agent/model");
 
         let agent: AgentState | null = null;
+        let isNewlyCreatedAgent = false;
 
         // Priority 1: Import from AgentFile template
         if (fromAfFile) {
@@ -1438,6 +1439,7 @@ async function main(): Promise<void> {
             stripMessages: true,
           });
           agent = result.agent;
+          isNewlyCreatedAgent = true;
           setAgentProvenance({
             isNew: true,
             blocks: [],
@@ -1531,6 +1533,7 @@ async function main(): Promise<void> {
             baseTools,
           );
           agent = result.agent;
+          isNewlyCreatedAgent = true;
           setAgentProvenance(result.provenance);
         }
 
@@ -1596,11 +1599,15 @@ async function main(): Promise<void> {
         // Set agent context for tools that need it (e.g., Skill tool)
         setAgentContext(agent.id, skillsDirectory);
 
-        // Apply memfs flag if specified
+        // Apply memfs flag if specified, or enable by default for new agents
+        const isSubagent = process.env.LETTA_CODE_AGENT_ROLE === "subagent";
         if (memfsFlag) {
           settingsManager.setMemfsEnabled(agent.id, true);
         } else if (noMemfsFlag) {
           settingsManager.setMemfsEnabled(agent.id, false);
+        } else if (isNewlyCreatedAgent && !isSubagent) {
+          // Enable memfs by default for newly created agents (but not subagents)
+          settingsManager.setMemfsEnabled(agent.id, true);
         }
 
         // Fire-and-forget: Initialize loaded skills flag (LET-7101)
@@ -1826,7 +1833,6 @@ async function main(): Promise<void> {
 
         // Save the session (agent + conversation) to settings
         // Skip for subagents - they shouldn't pollute the LRU settings
-        const isSubagent = process.env.LETTA_CODE_AGENT_ROLE === "subagent";
         if (!isSubagent) {
           settingsManager.setLocalLastSession(
             { agentId: agent.id, conversationId: conversationIdToUse },