From b67e94b9c1c4a5aa84c217877314bbcf93a64082 Mon Sep 17 00:00:00 2001
From: David Stone <david@nnucomputerwhiz.com>
Date: Tue, 17 Feb 2026 01:07:04 -0700
Subject: [PATCH] Fix: Handle array-style content blocks in messagesToPrompt

OpenAI API supports both string and array content formats for messages.
When content is an array of objects (e.g. [{"type": "text", "text": "..."}]),
JavaScript's template literal interpolation converts it to "[object Object]"
instead of the actual text content.

This adds an extractContent() helper that:
- Returns string content as-is
- Extracts and joins text from array-style content blocks
- Falls back to String() for any other type

All msg.content references in messagesToPrompt are updated to use
extractContent(msg.content) for the system, user, and assistant cases.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 src/adapter/openai-to-cli.ts | 27 ++++++++++++++++++++++++---
 1 file changed, 24 insertions(+), 3 deletions(-)

diff --git a/src/adapter/openai-to-cli.ts b/src/adapter/openai-to-cli.ts
index c8ecaa1..89a80da 100644
--- a/src/adapter/openai-to-cli.ts
+++ b/src/adapter/openai-to-cli.ts
@@ -46,6 +46,27 @@ export function extractModel(model: string): ClaudeModel {
   return "opus";
 }
 
+/**
+ * Extract text content from OpenAI message content.
+ *
+ * OpenAI API supports both string content and array-style content blocks
+ * (e.g. [{"type": "text", "text": "..."}]). When content is an array,
+ * naive string interpolation produces "[object Object]". This helper
+ * extracts the actual text from both formats.
+ */
+function extractContent(content: string | Array<{type: string; text?: string}>): string {
+  if (typeof content === "string") {
+    return content;
+  }
+  if (Array.isArray(content)) {
+    return content
+      .filter((block) => block.type === "text")
+      .map((block) => block.text ?? "")
+      .join("\n");
+  }
+  return String(content ?? "");
+}
+
 /**
  * Convert OpenAI messages array to a single prompt string for Claude CLI
  *
@@ -59,17 +80,17 @@ export function messagesToPrompt(messages: OpenAIChatRequest["messages"]): strin
     switch (msg.role) {
       case "system":
         // System messages become context instructions
-        parts.push(`<system>\n${msg.content}\n</system>\n`);
+        parts.push(`<system>\n${extractContent(msg.content)}\n</system>\n`);
         break;
 
       case "user":
         // User messages are the main prompt
-        parts.push(msg.content);
+        parts.push(extractContent(msg.content));
         break;
 
       case "assistant":
         // Previous assistant responses for context
-        parts.push(`<previous_response>\n${msg.content}\n</previous_response>\n`);
+        parts.push(`<previous_response>\n${extractContent(msg.content)}\n</previous_response>\n`);
         break;
     }
   }