diff --git a/v2/sidecar/agent-runner-deno.ts b/v2/sidecar/agent-runner-deno.ts
index 0808e36..6758d22 100644
--- a/v2/sidecar/agent-runner-deno.ts
+++ b/v2/sidecar/agent-runner-deno.ts
@@ -66,8 +66,13 @@ function handleQuery(msg: QueryMessage) {
 
   log(`Starting agent session ${sessionId}: claude ${args.join(" ")}`);
 
-  const env = { ...Deno.env.toObject() };
-  delete env.CLAUDECODE;
+  // Strip all CLAUDE* env vars to prevent nesting detection by claude CLI
+  const env: Record<string, string> = {};
+  for (const [key, value] of Object.entries(Deno.env.toObject())) {
+    if (!key.startsWith("CLAUDE")) {
+      env[key] = value;
+    }
+  }
 
   const command = new Deno.Command("claude", {
     args,
diff --git a/v2/sidecar/agent-runner.ts b/v2/sidecar/agent-runner.ts
index b82bace..ce22c09 100644
--- a/v2/sidecar/agent-runner.ts
+++ b/v2/sidecar/agent-runner.ts
@@ -89,13 +89,18 @@ function handleQuery(msg: QueryMessage) {
 
   log(`Starting agent session ${sessionId}: claude ${args.join(' ')}`);
 
+  // Strip all CLAUDE* env vars to prevent nesting detection by claude CLI.
+  // When BTerminal is launched from a Claude Code terminal, these leak in.
+  const cleanEnv: Record<string, string> = {};
+  for (const [key, value] of Object.entries(process.env)) {
+    if (!key.startsWith('CLAUDE') && value !== undefined) {
+      cleanEnv[key] = value;
+    }
+  }
+
   const child = spawn('claude', args, {
     cwd: cwd || process.cwd(),
-    env: {
-      ...process.env,
-      // Unset CLAUDECODE to avoid nesting detection
-      CLAUDECODE: undefined,
-    },
+    env: cleanEnv,
     stdio: ['pipe', 'pipe', 'pipe'],
   });