diff --git a/dist/index.js b/dist/index.js
index ead9809cabc9f3b203f1769db3cabb8327dd758a..113b166120711705edcabaca2d63ae40f46c7819 100755
--- a/dist/index.js
+++ b/dist/index.js
@@ -68,6 +68,15 @@ function shouldUseShellForPiCommand(cmd) {
   const normalized = cmd.trim().toLowerCase();
   return normalized.endsWith(".cmd") || normalized.endsWith(".bat");
 }
+function paperclipPiArgs() {
+  const raw = process.env.PI_ACP_PI_ARGS_JSON;
+  if (!raw) return [];
+  const parsed = JSON.parse(raw);
+  if (!Array.isArray(parsed) || parsed.length > 32 || parsed.some((value) => typeof value !== "string" || value.length > 4096)) {
+    throw new Error("PI_ACP_PI_ARGS_JSON must be a bounded JSON string array");
+  }
+  return parsed;
+}
 
 // src/pi-rpc/process.ts
 var PiRpcSpawnError = class extends Error {
@@ -132,7 +141,7 @@ var PiRpcProcess = class _PiRpcProcess {
   }
   static async spawn(params) {
     const cmd = getPiCommand(params.piCommand);
-    const args = ["--mode", "rpc", "--no-themes"];
+    const args = ["--mode", "rpc", "--no-themes", ...paperclipPiArgs()];
     if (params.sessionPath) args.push("--session", params.sessionPath);
     const child = spawn(cmd, args, {
       cwd: params.cwd,
@@ -173,6 +182,7 @@ var PiRpcProcess = class _PiRpcProcess {
       throw new PiRpcSpawnError(`Could not start pi (command: ${cmd}).`, { code, cause: e });
     }
-    child.stderr.on("data", () => {
+    child.stderr.on("data", (chunk) => {
+      process.stderr.write(chunk);
     });
     const proc = new _PiRpcProcess(child);
     try {
@@ -949,6 +959,22 @@ var PiAcpSession = class {
     switch (type) {
       case "message_update": {
         const ame = ev.assistantMessageEvent;
+        if (ev.usage && typeof ev.usage === "object") {
+          const usage = ev.usage;
+          const fingerprint = JSON.stringify(usage);
+          if (fingerprint !== this.paperclipUsageFingerprint && (usage.totalTokens ?? 0) > 0) {
+            this.paperclipUsageFingerprint = fingerprint;
+            process.stderr.write(`[paperclip-pi-usage-v1]${JSON.stringify({
+              inputTokens: typeof usage.input === "number" ? usage.input : void 0,
+              outputTokens: typeof usage.output === "number" ? usage.output : void 0,
+              cachedReadTokens: typeof usage.cacheRead === "number" ? usage.cacheRead : void 0,
+              cachedWriteTokens: typeof usage.cacheWrite === "number" ? usage.cacheWrite : void 0,
+              thoughtTokens: typeof usage.reasoning === "number" ? usage.reasoning : void 0,
+              totalTokens: typeof usage.totalTokens === "number" ? usage.totalTokens : void 0,
+              cost: typeof usage.cost?.total === "number" ? { amount: usage.cost.total, currency: "USD" } : void 0
+            })}\n`);
+          }
+        }
         if (ame?.type === "text_delta" && typeof ame.delta === "string") {
           this.emit({
             sessionUpdate: "agent_message_chunk",