From 4716712a924e9371c35adf39998a0e566ab88876 Mon Sep 17 00:00:00 2001
From: mitchell <m@mjfs.us>
Date: Fri, 17 Apr 2026 03:04:47 -0400
Subject: [PATCH] refactor: redirect reasoning output to stderr

---
 index.ts            | 22 +++++++-----------
 src/render/index.ts | 54 +++++++++++++++++++++++++--------------------
 2 files changed, 38 insertions(+), 38 deletions(-)

diff --git a/index.ts b/index.ts
index 28f306c..6a9fecd 100644
--- a/index.ts
+++ b/index.ts
@@ -78,25 +78,19 @@ async function main() {
   });
 
   const start = Date.now();
-
-  const streamRender = new StreamRenderer().renderStream(fullStream);
-
-  const [width] = process.stdout.getWindowSize();
-  const glow = Bun.spawn({
-    cmd: ["glow", "-w", `${width}`, "-"],
-    stdin: textStream,
-    stdout: "inherit",
-  });
-
-  await streamRender;
-
+  await new StreamRenderer().renderStream(fullStream);
   const stop = Date.now();
 
-  await glow.exited;
-
   convo.messages.push({ role: "assistant", content: await text });
   await convoFile.write(JSON.stringify(convo));
 
+  const [width] = process.stdout.getWindowSize();
+  await Bun.spawn({
+    cmd: ["glow", "-w", `${width}`, "-"],
+    stdin: textStream,
+    stdout: "inherit",
+  }).exited;
+
   const { inputTokens, outputTokens } = await totalUsage;
   const context = (inputTokens ?? 0) / 1000;
   const output = (outputTokens ?? 0) / 1000;
diff --git a/src/render/index.ts b/src/render/index.ts
index 774020b..581a3a8 100644
--- a/src/render/index.ts
+++ b/src/render/index.ts
@@ -1,7 +1,8 @@
 import os from "node:os";
+import type { WriteStream } from "node:tty";
 import type { AsyncIterableStream, TextStreamPart, ToolSet } from "ai";
 import styles from "ansi-styles";
-import { supportsColor } from "chalk";
+import { supportsColorStderr } from "chalk";
 
 const home = os.homedir();
 const reasoningWriter = Bun.file(`${home}/.aicl_reasoning.md`).writer();
@@ -15,18 +16,21 @@ export default class StreamRenderer {
     process.stdout.addListener("drain", () => {
       this.memOk = true;
     });
+    process.stderr.addListener("drain", () => {
+      this.memOk = true;
+    });
   }
 
-  private write(text: string) {
-    this.memOk = process.stdout.write(text);
+  private write(text: string, pipe: WriteStream = process.stdout) {
+    this.memOk = pipe.write(text);
   }
 
-  private moveCursor(x: number, y: number) {
-    this.memOk = process.stdout.moveCursor(x, y);
+  private moveCursor(y: number, pipe: WriteStream = process.stdout) {
+    this.memOk = pipe.moveCursor(-9999, y);
   }
 
-  private clearScreenDown() {
-    this.memOk = process.stdout.clearScreenDown();
+  private clearScreenDown(pipe: WriteStream = process.stdout) {
+    this.memOk = pipe.clearScreenDown();
   }
 
   private resetCounts() {
@@ -34,8 +38,8 @@ export default class StreamRenderer {
     this.charsSinceNL = 0;
   }
 
-  private checkContainment(text: string) {
-    const [columns, rows] = process.stdout.getWindowSize();
+  private checkContainment(text: string, pipe: WriteStream = process.stdout) {
+    const [columns, rows] = pipe.getWindowSize();
     this.charsSinceNL += text.length;
     if (text.includes("\n")) {
       this.lineCount += text.match(/\n/g)?.length ?? 1;
@@ -46,10 +50,9 @@ export default class StreamRenderer {
     }
 
     if (this.lineCount >= Math.floor(rows * 0.75)) {
-      this.moveCursor(0, -this.lineCount);
-      this.clearScreenDown();
-      this.lineCount = 0;
-      this.charsSinceNL = 0;
+      this.moveCursor(-this.lineCount, pipe);
+      this.clearScreenDown(pipe);
+      this.resetCounts();
     }
   }
 
@@ -58,18 +61,21 @@ export default class StreamRenderer {
 
     for await (const part of stream) {
       if (part.type === "reasoning-start") {
-        if (supportsColor)
-          this.write(`${styles.dim.open}${styles.italic.open}`);
-        this.write("\n");
+        if (supportsColorStderr)
+          this.write(`${styles.dim.open}${styles.italic.open}`, process.stderr);
+        this.write("\n", process.stderr);
       } else if (part.type === "reasoning-delta") {
-        this.write(part.text);
+        this.write(part.text, process.stderr);
         reasoningWriter.write(part.text);
-        this.checkContainment(part.text);
+        this.checkContainment(part.text, process.stderr);
       } else if (part.type === "reasoning-end") {
-        if (supportsColor)
-          this.write(`${styles.italic.close}${styles.dim.close}`);
-        this.moveCursor(0, -this.lineCount - 1);
-        this.clearScreenDown();
+        if (supportsColorStderr)
+          this.write(
+            `${styles.italic.close}${styles.dim.close}`,
+            process.stderr,
+          );
+        this.moveCursor(-this.lineCount - 1, process.stderr);
+        this.clearScreenDown(process.stderr);
         this.resetCounts();
         reasoningWriter.end();
       } else if (part.type === "text-start") {
@@ -78,8 +84,8 @@ export default class StreamRenderer {
         this.write(part.text);
         this.checkContainment(part.text);
       } else if (part.type === "text-end") {
-        this.moveCursor(0, -this.lineCount - 1);
-        this.clearScreenDown();
+        this.moveCursor(-this.lineCount - 1);
+        this.clearScreenDown(process.stderr);
         this.resetCounts();
       }