diff --git a/src/agent-manager.ts b/src/agent-manager.ts
index cf79e7d..1c724c3 100644
--- a/src/agent-manager.ts
+++ b/src/agent-manager.ts
@@ -10,6 +10,13 @@ import {
 import { join } from "node:path";
 import { execFileSync } from "node:child_process";
 import { CONFIG } from "./config.js";
+
+const SSH_OPTS = [
+  "-o", "StrictHostKeyChecking=no",
+  "-o", "UserKnownHostsFile=/dev/null",
+  "-o", "ConnectTimeout=5",
+  "-i", CONFIG.sshKeyPath,
+];
 import {
   allocateIp,
   releaseIp,
@@ -103,7 +110,7 @@ function injectAgentConfig(
       { stdio: "pipe" }
     );
 
-    // Write config
+    // Write config (via stdin to avoid shell injection)
     const configJson = JSON.stringify({
       nick: config.nick,
       model: config.model,
@@ -112,26 +119,18 @@ function injectAgentConfig(
       port: 6667,
       ollama_url: "http://172.16.0.1:11434",
     });
-    execFileSync(
-      "sudo",
-      [
-        "bash",
-        "-c",
-        `echo '${configJson}' > ${join(mountPoint, "etc/agent/config.json")}`,
-      ],
-      { stdio: "pipe" }
-    );
+    const configPath = join(mountPoint, "etc/agent/config.json");
+    execFileSync("sudo", ["tee", configPath], {
+      input: configJson,
+      stdio: ["pipe", "pipe", "pipe"],
+    });
 
-    // Write persona
-    execFileSync(
-      "sudo",
-      [
-        "bash",
-        "-c",
-        `cat > ${join(mountPoint, "etc/agent/persona.md")} << 'PERSONA_EOF'\n${persona}\nPERSONA_EOF`,
-      ],
-      { stdio: "pipe" }
-    );
+    // Write persona (via stdin to avoid shell injection)
+    const personaPath = join(mountPoint, "etc/agent/persona.md");
+    execFileSync("sudo", ["tee", personaPath], {
+      input: persona,
+      stdio: ["pipe", "pipe", "pipe"],
+    });
 
     // Inject SSH key for debugging access
     execFileSync("sudo", ["mkdir", "-p", join(mountPoint, "root/.ssh")], {
@@ -301,14 +300,7 @@ export async function stopAgent(name: string) {
   try {
     execFileSync(
       "ssh",
-      [
-        "-o", "StrictHostKeyChecking=no",
-        "-o", "UserKnownHostsFile=/dev/null",
-        "-o", "ConnectTimeout=3",
-        "-i", CONFIG.sshKeyPath,
-        `root@${info.ip}`,
-        "killall python3 2>/dev/null; sleep 1",
-      ],
+      [...SSH_OPTS, `root@${info.ip}`, "killall python3 2>/dev/null; sleep 1"],
       { stdio: "pipe", timeout: 5_000 }
     );
   } catch {
@@ -405,13 +397,6 @@ export async function reloadAgent(
   }
   if (updates.trigger) configUpdates.trigger = updates.trigger;
 
-  // Write updated config as a temp file on the VM via SSH
-  const sshOpts = [
-    "-o", "StrictHostKeyChecking=no",
-    "-o", "UserKnownHostsFile=/dev/null",
-    "-o", "ConnectTimeout=5",
-    "-i", CONFIG.sshKeyPath,
-  ];
   const sshTarget = `root@${info.ip}`;
 
   try {
@@ -419,7 +404,7 @@ export async function reloadAgent(
       // Read current config from VM
       const currentRaw = execFileSync(
         "ssh",
-        [...sshOpts, sshTarget, "cat /etc/agent/config.json"],
+        [...SSH_OPTS, sshTarget, "cat /etc/agent/config.json"],
         { encoding: "utf-8", timeout: 10_000 }
       );
       const current = JSON.parse(currentRaw);
@@ -429,7 +414,7 @@ export async function reloadAgent(
       // Write back via stdin
       execFileSync(
         "ssh",
-        [...sshOpts, sshTarget, `cat > /etc/agent/config.json`],
+        [...SSH_OPTS, sshTarget, `cat > /etc/agent/config.json`],
         { input: newConfig, timeout: 10_000 }
       );
     }
@@ -437,7 +422,7 @@ export async function reloadAgent(
     if (updates.persona) {
       execFileSync(
         "ssh",
-        [...sshOpts, sshTarget, `cat > /etc/agent/persona.md`],
+        [...SSH_OPTS, sshTarget, `cat > /etc/agent/persona.md`],
         { input: updates.persona, timeout: 10_000 }
       );
     }
@@ -445,7 +430,7 @@ export async function reloadAgent(
     // Signal agent to reload
     execFileSync(
       "ssh",
-      [...sshOpts, sshTarget, "killall -HUP python3"],
+      [...SSH_OPTS, sshTarget, "killall -HUP python3"],
       { stdio: "pipe", timeout: 10_000 }
     );
   } catch (err) {