From a13fb37d87f5392ee9b4a6cd4a1b5c077191418c Mon Sep 17 00:00:00 2001
From: Charles Packer <packercharles@gmail.com>
Date: Fri, 20 Feb 2026 12:57:40 -0800
Subject: [PATCH] feat: auto-enable memfs from server-side tag on new machines
 (#1063)

Co-authored-by: Letta <noreply@letta.com>
---
 src/agent/memoryFilesystem.ts | 43 +++++++++++++++++++++++++++--------
 src/agent/memoryGit.ts        |  2 +-
 src/headless.ts               |  4 ++--
 src/index.ts                  |  6 +++--
 4 files changed, 41 insertions(+), 14 deletions(-)

diff --git a/src/agent/memoryFilesystem.ts b/src/agent/memoryFilesystem.ts
index f515b00..f491485 100644
--- a/src/agent/memoryFilesystem.ts
+++ b/src/agent/memoryFilesystem.ts
@@ -143,6 +143,11 @@ export interface ApplyMemfsFlagsResult {
   pullSummary?: string;
 }
 
+export interface ApplyMemfsFlagsOptions {
+  pullOnExistingRepo?: boolean;
+  agentTags?: string[];
+}
+
 /**
  * Apply --memfs / --no-memfs CLI flags (or /memfs enable) to an agent.
  *
@@ -162,7 +167,7 @@ export async function applyMemfsFlags(
   agentId: string,
   memfsFlag: boolean | undefined,
   noMemfsFlag: boolean | undefined,
-  options?: { pullOnExistingRepo?: boolean },
+  options?: ApplyMemfsFlagsOptions,
 ): Promise<ApplyMemfsFlagsResult> {
   const { getServerUrl } = await import("./client");
   const { settingsManager } = await import("../settings-manager");
@@ -181,14 +186,22 @@ export async function applyMemfsFlags(
   }
 
   const hasExplicitToggle = Boolean(memfsFlag || noMemfsFlag);
+  const localMemfsEnabled = settingsManager.isMemfsEnabled(agentId);
+  const { GIT_MEMORY_ENABLED_TAG } = await import("./memoryGit");
+  const shouldAutoEnableFromTag =
+    !hasExplicitToggle &&
+    !localMemfsEnabled &&
+    Boolean(options?.agentTags?.includes(GIT_MEMORY_ENABLED_TAG));
   const targetEnabled = memfsFlag
     ? true
     : noMemfsFlag
       ? false
-      : settingsManager.isMemfsEnabled(agentId);
+      : shouldAutoEnableFromTag
+        ? true
+        : localMemfsEnabled;
 
   // 2. Reconcile system prompt first, then persist local memfs setting.
-  if (hasExplicitToggle) {
+  if (hasExplicitToggle || shouldAutoEnableFromTag) {
     const { updateAgentSystemPromptMemfs } = await import("./modify");
     const promptUpdate = await updateAgentSystemPromptMemfs(
       agentId,
@@ -200,16 +213,23 @@ export async function applyMemfsFlags(
     settingsManager.setMemfsEnabled(agentId, targetEnabled);
   }
 
-  const isEnabled = hasExplicitToggle
-    ? targetEnabled
-    : settingsManager.isMemfsEnabled(agentId);
+  const isEnabled =
+    hasExplicitToggle || shouldAutoEnableFromTag
+      ? targetEnabled
+      : settingsManager.isMemfsEnabled(agentId);
 
-  // 3. Detach old API-based memory tools when explicitly enabling.
-  if (isEnabled && memfsFlag) {
+  // 3. Detach old API-based memory tools when enabling.
+  if (isEnabled && (memfsFlag || shouldAutoEnableFromTag)) {
     const { detachMemoryTools } = await import("../tools/toolset");
     await detachMemoryTools(agentId);
   }
 
+  // Keep server-side state aligned with explicit disable.
+  if (noMemfsFlag) {
+    const { removeGitMemoryTag } = await import("./memoryGit");
+    await removeGitMemoryTag(agentId);
+  }
+
   // 4. Add git tag + clone/pull repo.
   let pullSummary: string | undefined;
   if (isEnabled) {
@@ -224,7 +244,12 @@ export async function applyMemfsFlags(
     }
   }
 
-  const action = memfsFlag ? "enabled" : noMemfsFlag ? "disabled" : "unchanged";
+  const action =
+    memfsFlag || shouldAutoEnableFromTag
+      ? "enabled"
+      : noMemfsFlag
+        ? "disabled"
+        : "unchanged";
   return {
     action,
     memoryDir: isEnabled ? getMemoryFilesystemRoot(agentId) : undefined,
diff --git a/src/agent/memoryGit.ts b/src/agent/memoryGit.ts
index 001fbc1..530406b 100644
--- a/src/agent/memoryGit.ts
+++ b/src/agent/memoryGit.ts
@@ -26,7 +26,7 @@ import { getClient, getServerUrl } from "./client";
 
 const execFile = promisify(execFileCb);
 
-const GIT_MEMORY_ENABLED_TAG = "git-memory-enabled";
+export const GIT_MEMORY_ENABLED_TAG = "git-memory-enabled";
 
 /** Get the agent root directory (~/.letta/agents/{id}/) */
 export function getAgentRootDir(agentId: string): string {
diff --git a/src/headless.ts b/src/headless.ts
index 98c499b..688891c 100644
--- a/src/headless.ts
+++ b/src/headless.ts
@@ -916,14 +916,14 @@ export async function handleHeadlessCommand(
 
   const isSubagent = process.env.LETTA_CODE_AGENT_ROLE === "subagent";
 
-  // Apply memfs flag if explicitly specified (memfs is opt-in via /memfs enable or --memfs)
+  // Apply memfs flags and auto-enable from server tag when local settings are missing.
   try {
     const { applyMemfsFlags } = await import("./agent/memoryFilesystem");
     const memfsResult = await applyMemfsFlags(
       agent.id,
       memfsFlag,
       noMemfsFlag,
-      { pullOnExistingRepo: true },
+      { pullOnExistingRepo: true, agentTags: agent.tags },
     );
     if (memfsResult.pullSummary?.includes("CONFLICT")) {
       console.error(
diff --git a/src/index.ts b/src/index.ts
index 08d3a1f..f38be75 100755
--- a/src/index.ts
+++ b/src/index.ts
@@ -1767,11 +1767,13 @@ async function main(): Promise<void> {
         // Set agent context for tools that need it (e.g., Skill tool)
         setAgentContext(agent.id, skillsDirectory, resolvedSkillSources);
 
-        // Apply memfs flag if explicitly specified (memfs is opt-in via /memfs enable or --memfs)
+        // Apply memfs flags and auto-enable from server tag when local settings are missing.
         const isSubagent = process.env.LETTA_CODE_AGENT_ROLE === "subagent";
         try {
           const { applyMemfsFlags } = await import("./agent/memoryFilesystem");
-          await applyMemfsFlags(agent.id, memfsFlag, noMemfsFlag);
+          await applyMemfsFlags(agent.id, memfsFlag, noMemfsFlag, {
+            agentTags: agent.tags,
+          });
         } catch (error) {
           console.error(error instanceof Error ? error.message : String(error));
           process.exit(1);