diff --git a/src/cli/App.tsx b/src/cli/App.tsx
index 985f983..4907ed0 100644
--- a/src/cli/App.tsx
+++ b/src/cli/App.tsx
@@ -1456,22 +1456,33 @@ export default function App({
         ? `Resuming conversation with **${agentName}**`
         : `Starting new conversation with **${agentName}**`;
 
-      // Command hints - for pinned agents show /memory, for unpinned show /pin
-      const commandHints = isPinned
+      // Command hints - vary based on agent state:
+      // - Resuming: show /new (they may want a fresh conversation)
+      // - New session + unpinned: show /pin (they should save their agent)
+      // - New session + pinned: show /memory (they're already saved)
+      const commandHints = isResumingConversation
         ? [
             "→ **/agents**    list all agents",
-            "→ **/resume**    resume a previous conversation",
-            "→ **/memory**    view your agent's memory blocks",
+            "→ **/resume**    browse all conversations",
+            "→ **/new**       start a new conversation",
             "→ **/init**      initialize your agent's memory",
             "→ **/remember**  teach your agent",
           ]
-        : [
-            "→ **/agents**    list all agents",
-            "→ **/resume**    resume a previous conversation",
-            "→ **/pin**       save + name your agent",
-            "→ **/init**      initialize your agent's memory",
-            "→ **/remember**  teach your agent",
-          ];
+        : isPinned
+          ? [
+              "→ **/agents**    list all agents",
+              "→ **/resume**    resume a previous conversation",
+              "→ **/memory**    view your agent's memory blocks",
+              "→ **/init**      initialize your agent's memory",
+              "→ **/remember**  teach your agent",
+            ]
+          : [
+              "→ **/agents**    list all agents",
+              "→ **/resume**    resume a previous conversation",
+              "→ **/pin**       save + name your agent",
+              "→ **/init**      initialize your agent's memory",
+              "→ **/remember**  teach your agent",
+            ];
 
       // Build status lines with optional release notes above header
       const statusLines: string[] = [];
@@ -3185,13 +3196,9 @@ export default function App({
         // Fetch new agent
         const agent = await client.agents.retrieve(targetAgentId);
 
-        // Always create a new conversation when switching agents
-        // User can /resume to get back to a previous conversation if needed
-        const newConversation = await client.conversations.create({
-          agent_id: targetAgentId,
-          isolated_block_labels: [...ISOLATED_BLOCK_LABELS],
-        });
-        const targetConversationId = newConversation.id;
+        // Use the agent's default conversation when switching agents
+        // User can /new to start a fresh conversation if needed
+        const targetConversationId = "default";
 
         // Update project settings with new agent
         await updateProjectSettings({ lastAgent: targetAgentId });
@@ -3225,11 +3232,12 @@ export default function App({
         setLlmConfig(agent.llm_config);
         setConversationId(targetConversationId);
 
-        // Build success message - always a new conversation
+        // Build success message - resumed default conversation
         const agentLabel = agent.name || targetAgentId;
         const successOutput = [
-          `Started a new conversation with **${agentLabel}**.`,
-          `⎿  Type /resume to resume a previous conversation`,
+          `Resumed the default conversation with **${agentLabel}**.`,
+          `⎿  Type /resume to browse all conversations`,
+          `⎿  Type /new to start a new conversation`,
         ].join("\n");
         const successItem: StaticItem = {
           kind: "command",
@@ -4270,9 +4278,8 @@ export default function App({
           return { submitted: true };
         }
 
-        // Special handling for /clear and /new commands - start new conversation
-        // (/new used to create a new agent, now it's just an alias for /clear)
-        if (msg.trim() === "/clear" || msg.trim() === "/new") {
+        // Special handling for /new command - start new conversation
+        if (msg.trim() === "/new") {
           const cmdId = uid("cmd");
           buffersRef.current.byId.set(cmdId, {
             kind: "command",
@@ -4339,14 +4346,14 @@ export default function App({
           return { submitted: true };
         }
 
-        // Special handling for /clear-messages command - reset all agent messages (destructive)
-        if (msg.trim() === "/clear-messages") {
+        // Special handling for /clear command - reset all agent messages (destructive)
+        if (msg.trim() === "/clear") {
           const cmdId = uid("cmd");
           buffersRef.current.byId.set(cmdId, {
             kind: "command",
             id: cmdId,
             input: msg,
-            output: "Resetting agent messages...",
+            output: "Clearing in-context messages...",
             phase: "running",
           });
           buffersRef.current.order.push(cmdId);
@@ -7917,11 +7924,16 @@ Plan file path: ${planFilePath}`;
                     ? `letta -n "${agentName}"`
                     : `letta --agent ${agentId}`}
                 </Text>
-                <Text> </Text>
-                <Text dimColor>Resume this conversation with:</Text>
-                <Text color={colors.link.url}>
-                  {`letta --conv ${conversationId}`}
-                </Text>
+                {/* Only show conversation hint if not on default (default is resumed automatically) */}
+                {conversationId !== "default" && (
+                  <>
+                    <Text> </Text>
+                    <Text dimColor>Resume this conversation with:</Text>
+                    <Text color={colors.link.url}>
+                      {`letta --conv ${conversationId}`}
+                    </Text>
+                  </>
+                )}
               </Box>
             )}
 
diff --git a/src/cli/commands/registry.ts b/src/cli/commands/registry.ts
index ac373c4..0dc44fd 100644
--- a/src/cli/commands/registry.ts
+++ b/src/cli/commands/registry.ts
@@ -77,29 +77,20 @@ export const commands: Record<string, Command> = {
     },
   },
   "/clear": {
-    desc: "Start a new conversation (keep agent memory)",
+    desc: "Clear in-context messages",
     order: 18,
-    handler: () => {
-      // Handled specially in App.tsx to create new conversation
-      return "Starting new conversation...";
-    },
-  },
-  "/clear-messages": {
-    desc: "Reset all agent messages (destructive)",
-    order: 19,
-    hidden: true, // Advanced command, not shown in autocomplete
     handler: () => {
       // Handled specially in App.tsx to reset agent messages
-      return "Resetting agent messages...";
+      return "Clearing in-context messages...";
     },
   },
 
   // === Page 2: Agent management (order 20-29) ===
   "/new": {
-    desc: "Start a new conversation (same as /clear)",
+    desc: "Start a new conversation (keep agent memory)",
     order: 20,
     handler: () => {
-      // Handled specially in App.tsx - same as /clear
+      // Handled specially in App.tsx to create new conversation
       return "Starting new conversation...";
     },
   },
@@ -334,7 +325,6 @@ export const commands: Record<string, Command> = {
   },
   "/compact": {
     desc: "Summarize conversation history (compaction)",
-    hidden: true,
     handler: () => {
       // Handled specially in App.tsx to access client and agent ID
       return "Compacting conversation...";
diff --git a/src/headless.ts b/src/headless.ts
index 4dcbbf4..7a0a0d4 100644
--- a/src/headless.ts
+++ b/src/headless.ts
@@ -191,14 +191,8 @@ export async function handleHeadlessCommand(
     process.exit(1);
   }
 
-  // Check for deprecated --new flag
-  if (values.new) {
-    console.error(
-      "Error: --new has been renamed to --new-agent\n" +
-        'Usage: letta -p "..." --new-agent',
-    );
-    process.exit(1);
-  }
+  // --new: Create a new conversation (for concurrent sessions)
+  const forceNewConversation = (values.new as boolean | undefined) ?? false;
 
   // Resolve agent (same logic as interactive mode)
   let agent: AgentState | null = null;
@@ -269,6 +263,18 @@ export async function handleHeadlessCommand(
     }
   }
 
+  // Validate --new flag (create new conversation)
+  if (forceNewConversation) {
+    if (shouldContinue) {
+      console.error("Error: --new cannot be used with --continue");
+      process.exit(1);
+    }
+    if (specifiedConversationId) {
+      console.error("Error: --new cannot be used with --conversation");
+      process.exit(1);
+    }
+  }
+
   // Validate --from-af flag
   if (fromAfFile) {
     if (specifiedAgentId) {
@@ -617,30 +623,35 @@ export async function handleHeadlessCommand(
           await client.conversations.retrieve(lastSession.conversationId);
           conversationId = lastSession.conversationId;
         } catch {
-          // Conversation no longer exists, create new
-          const conversation = await client.conversations.create({
-            agent_id: agent.id,
-            isolated_block_labels: isolatedBlockLabels,
-          });
-          conversationId = conversation.id;
+          // Conversation no longer exists - error with helpful message
+          console.error(
+            `Attempting to resume conversation ${lastSession.conversationId}, but conversation was not found.`,
+          );
+          console.error(
+            "Resume the default conversation with 'letta -p ...', view recent conversations with 'letta --resume', or start a new conversation with 'letta -p ... --new'.",
+          );
+          process.exit(1);
         }
       }
     } else {
-      // No matching session, create new conversation
-      const conversation = await client.conversations.create({
-        agent_id: agent.id,
-        isolated_block_labels: isolatedBlockLabels,
-      });
-      conversationId = conversation.id;
+      // No matching session - error with helpful message
+      console.error("No previous session found for this agent to resume.");
+      console.error(
+        "Resume the default conversation with 'letta -p ...', or start a new conversation with 'letta -p ... --new'.",
+      );
+      process.exit(1);
     }
-  } else {
-    // Default: create a new conversation
-    // This ensures isolated message history per CLI invocation
+  } else if (forceNewConversation || forceNew) {
+    // --new flag (new conversation) or --new-agent (new agent): create a new conversation
+    // When creating a new agent, always create a new conversation alongside it
     const conversation = await client.conversations.create({
       agent_id: agent.id,
       isolated_block_labels: isolatedBlockLabels,
     });
     conversationId = conversation.id;
+  } else {
+    // Default: use the agent's "default" conversation (OG single-threaded behavior)
+    conversationId = "default";
   }
   markMilestone("HEADLESS_CONVERSATION_READY");
 
diff --git a/src/index.ts b/src/index.ts
index 3480340..1bd4ef3 100755
--- a/src/index.ts
+++ b/src/index.ts
@@ -63,10 +63,11 @@ Letta Code is a general purpose CLI for interacting with Letta agents
 
 USAGE
   # interactive TUI
-  letta                 Resume from profile or create new agent (shows selector)
+  letta                 Resume default conversation (OG single-threaded experience)
+  letta --new           Create a new conversation (for concurrent sessions)
   letta --continue      Resume last session (agent + conversation) directly
   letta --resume        Open agent selector UI to pick agent/conversation
-  letta --new           Create a new agent directly (skip profile selector)
+  letta --new-agent     Create a new agent directly (skip profile selector)
   letta --agent <id>    Open a specific agent by ID
 
   # headless
@@ -81,9 +82,10 @@ OPTIONS
   --info                Show current directory, skills, and pinned agents
   --continue            Resume last session (agent + conversation) directly
   -r, --resume          Open agent selector UI after loading
-  --new                 Create new agent directly (skip profile selection)
-  --init-blocks <list>  Comma-separated memory blocks to initialize when using --new (e.g., "persona,skills")
-  --base-tools <list>   Comma-separated base tools to attach when using --new (e.g., "memory,web_search,conversation_search")
+  --new                 Create new conversation (for concurrent sessions)
+  --new-agent           Create new agent directly (skip profile selection)
+  --init-blocks <list>  Comma-separated memory blocks to initialize when using --new-agent (e.g., "persona,skills")
+  --base-tools <list>   Comma-separated base tools to attach when using --new-agent (e.g., "memory,web_search,conversation_search")
   -a, --agent <id>      Use a specific agent ID
   -n, --name <name>     Resume agent by name (from pinned agents, case-insensitive)
   -m, --model <id>      Model ID or handle (e.g., "opus-4.5" or "anthropic/claude-opus-4-5")
@@ -489,14 +491,8 @@ async function main(): Promise<void> {
     specifiedConversationId = "default";
   }
 
-  // Check for deprecated --new flag
-  if (values.new) {
-    console.error(
-      "Error: --new has been renamed to --new-agent\n" +
-        "Usage: letta --new-agent",
-    );
-    process.exit(1);
-  }
+  // --new: Create a new conversation (for concurrent sessions)
+  const forceNewConversation = (values.new as boolean | undefined) ?? false;
 
   const initBlocksRaw = values["init-blocks"] as string | undefined;
   const baseToolsRaw = values["base-tools"] as string | undefined;
@@ -686,6 +682,22 @@ async function main(): Promise<void> {
     }
   }
 
+  // Validate --new flag (create new conversation)
+  if (forceNewConversation) {
+    if (shouldContinue) {
+      console.error("Error: --new cannot be used with --continue");
+      process.exit(1);
+    }
+    if (specifiedConversationId) {
+      console.error("Error: --new cannot be used with --conversation");
+      process.exit(1);
+    }
+    if (shouldResume) {
+      console.error("Error: --new cannot be used with --resume");
+      process.exit(1);
+    }
+  }
+
   // Validate --from-af flag
   if (fromAfFile) {
     if (specifiedAgentId) {
@@ -1687,12 +1699,14 @@ async function main(): Promise<void> {
           }
 
           if (!resumedSuccessfully) {
-            // No valid session to resume for this agent, or it failed - create new
-            const conversation = await client.conversations.create({
-              agent_id: agent.id,
-              isolated_block_labels: [...ISOLATED_BLOCK_LABELS],
-            });
-            conversationIdToUse = conversation.id;
+            // No valid session to resume - error with helpful message
+            console.error(
+              `Attempting to resume conversation ${lastSession?.conversationId ?? "(unknown)"}, but conversation was not found.`,
+            );
+            console.error(
+              "Resume the default conversation with 'letta', view recent conversations with 'letta --resume', or start a new conversation with 'letta --new'.",
+            );
+            process.exit(1);
           }
         } else if (selectedConversationId) {
           // User selected a specific conversation from the --resume selector
@@ -1717,14 +1731,24 @@ async function main(): Promise<void> {
             }
             throw error;
           }
-        } else {
-          // Default: create a new conversation on startup
-          // This ensures each CLI session has isolated message history
+        } else if (forceNewConversation || forceNew) {
+          // --new flag (new conversation) or --new-agent (new agent): create a new conversation
+          // When creating a new agent, always create a new conversation alongside it
           const conversation = await client.conversations.create({
             agent_id: agent.id,
             isolated_block_labels: [...ISOLATED_BLOCK_LABELS],
           });
           conversationIdToUse = conversation.id;
+        } else {
+          // Default: use the agent's "default" conversation (OG single-threaded behavior)
+          conversationIdToUse = "default";
+
+          // Load message history from the default conversation
+          setLoadingState("checking");
+          const freshAgent = await client.agents.retrieve(agent.id);
+          const data = await getResumeData(client, freshAgent, "default");
+          setResumeData(data);
+          setResumedExistingConversation(true);
         }
 
         // Save the session (agent + conversation) to settings
diff --git a/src/release-notes.ts b/src/release-notes.ts
index dbd3a57..bc572a3 100644
--- a/src/release-notes.ts
+++ b/src/release-notes.ts
@@ -17,6 +17,10 @@ export const releaseNotes: Record<string, string> = {
   // Add release notes for new versions here.
   // Keep concise - 3-4 bullet points max.
   // Use → for bullets to match the command hints below.
+  "0.13.4": `🔄 **Letta Code 0.13.4: Back to the OG experience**
+→ Running **letta** now resumes your "default" conversation (instead of spawning a new one)
+→ Use **letta --new** if you want to create a new conversation for concurrent sessions
+→ Read more: https://docs.letta.com/letta-code/changelog#0134`,
   "0.13.0": `🎁 **Letta Code 0.13.0: Introducing Conversations!**
 → Letta Code now starts a new conversation on each startup (memory is shared across all conversations)
 → Use **/resume** to switch conversations, or run **letta --continue** to continue an existing conversation
diff --git a/src/tests/headless-input-format.test.ts b/src/tests/headless-input-format.test.ts
index 1148bb2..7c3045e 100644
--- a/src/tests/headless-input-format.test.ts
+++ b/src/tests/headless-input-format.test.ts
@@ -46,7 +46,8 @@ async function runBidirectional(
       ],
       {
         cwd: process.cwd(),
-        env: { ...process.env },
+        // Mark as subagent to prevent polluting user's LRU settings
+        env: { ...process.env, LETTA_CODE_AGENT_ROLE: "subagent" },
       },
     );
 
diff --git a/src/tests/headless-scenario.ts b/src/tests/headless-scenario.ts
index 7a73e39..437d1be 100644
--- a/src/tests/headless-scenario.ts
+++ b/src/tests/headless-scenario.ts
@@ -76,7 +76,12 @@ async function runCLI(
     "-m",
     model,
   ];
-  const proc = Bun.spawn(cmd, { stdout: "pipe", stderr: "pipe" });
+  // Mark as subagent to prevent polluting user's LRU settings
+  const proc = Bun.spawn(cmd, {
+    stdout: "pipe",
+    stderr: "pipe",
+    env: { ...process.env, LETTA_CODE_AGENT_ROLE: "subagent" },
+  });
   const out = await new Response(proc.stdout).text();
   const err = await new Response(proc.stderr).text();
   const code = await proc.exited;
diff --git a/src/tests/headless-stream-json-format.test.ts b/src/tests/headless-stream-json-format.test.ts
index 1953bee..231ce70 100644
--- a/src/tests/headless-stream-json-format.test.ts
+++ b/src/tests/headless-stream-json-format.test.ts
@@ -34,7 +34,8 @@ async function runHeadlessCommand(
       ],
       {
         cwd: process.cwd(),
-        env: { ...process.env },
+        // Mark as subagent to prevent polluting user's LRU settings
+        env: { ...process.env, LETTA_CODE_AGENT_ROLE: "subagent" },
       },
     );
 
diff --git a/src/tests/headless-windows.ts b/src/tests/headless-windows.ts
index 5ed71c5..37d829f 100644
--- a/src/tests/headless-windows.ts
+++ b/src/tests/headless-windows.ts
@@ -67,7 +67,12 @@ async function runCLI(
     "-m",
     model,
   ];
-  const proc = Bun.spawn(cmd, { stdout: "pipe", stderr: "pipe" });
+  // Mark as subagent to prevent polluting user's LRU settings
+  const proc = Bun.spawn(cmd, {
+    stdout: "pipe",
+    stderr: "pipe",
+    env: { ...process.env, LETTA_CODE_AGENT_ROLE: "subagent" },
+  });
   const out = await new Response(proc.stdout).text();
   const err = await new Response(proc.stderr).text();
   const code = await proc.exited;
diff --git a/src/tests/lazy-approval-recovery.test.ts b/src/tests/lazy-approval-recovery.test.ts
index 3273227..f498ec5 100644
--- a/src/tests/lazy-approval-recovery.test.ts
+++ b/src/tests/lazy-approval-recovery.test.ts
@@ -64,7 +64,8 @@ async function runLazyRecoveryTest(timeoutMs = 180000): Promise<{
       ],
       {
         cwd: process.cwd(),
-        env: { ...process.env },
+        // Mark as subagent to prevent polluting user's LRU settings
+        env: { ...process.env, LETTA_CODE_AGENT_ROLE: "subagent" },
       },
     );
 
diff --git a/src/tests/startup-flow.test.ts b/src/tests/startup-flow.test.ts
index 5ba9c03..47c2775 100644
--- a/src/tests/startup-flow.test.ts
+++ b/src/tests/startup-flow.test.ts
@@ -30,7 +30,8 @@ async function runCli(
   return new Promise((resolve, reject) => {
     const proc = spawn("bun", ["run", "dev", ...args], {
       cwd: projectRoot,
-      env: { ...process.env },
+      // Mark as subagent to prevent polluting user's LRU settings
+      env: { ...process.env, LETTA_CODE_AGENT_ROLE: "subagent" },
     });
 
     let stdout = "";