Fix [object Object] serialization issue with multi-modal content

README.md

@@ -120,15 +120,59 @@ curl -N -X POST http://localhost:3456/v1/chat/completions \
 
 ## Configuration with Popular Tools
 
-### Clawdbot
+### OpenClaw / Clawdbot
 
-Clawdbot has **built-in support** for Claude CLI OAuth! Check your config:
+Add the following to your `~/.openclaw/openclaw.json` (or equivalent config file):
 
-```bash
-clawdbot models status
+```json
+{
+  "models": {
+    "providers": {
+      "claude-max-proxy": {
+        "baseUrl": "http://localhost:3456/v1",
+        "apiKey": "not-needed",
+        "api": "openai-completions",
+        "models": [
+          {
+            "id": "claude-opus-4",
+            "name": "Claude Opus 4 (via Max Proxy)",
+            "reasoning": true,
+            "input": ["text"],
+            "cost": { "input": 0, "output": 0, "cacheRead": 0, "cacheWrite": 0 },
+            "contextWindow": 200000,
+            "maxTokens": 32000
+          },
+          {
+            "id": "claude-sonnet-4",
+            "name": "Claude Sonnet 4 (via Max Proxy)",
+            "reasoning": true,
+            "input": ["text"],
+            "cost": { "input": 0, "output": 0, "cacheRead": 0, "cacheWrite": 0 },
+            "contextWindow": 200000,
+            "maxTokens": 32000
+          }
+        ]
+      }
+    }
+  },
+  "agents": {
+    "defaults": {
+      "model": {
+        "primary": "claude-max-proxy/claude-opus-4"
+      },
+      "models": {
+        "claude-max-proxy/claude-opus-4": { "alias": "opus4" },
+        "claude-max-proxy/claude-sonnet-4": { "alias": "sonnet4" }
+      }
+    }
+  }
+}
 ```
 
-If you see `anthropic:claude-cli=OAuth`, you're already using your Max subscription.
+**Important:** Make sure the proxy server is running before starting OpenClaw:
+```bash
+claude-max-api  # or: node dist/server/standalone.js
+```
 
 ### Continue.dev
 

src/adapter/cli-to-openai.ts

@@ -62,6 +62,33 @@ export function createDoneChunk(requestId: string, model: string): OpenAIChatChu
   };
 }
 
+/**
+ * Ensure content is always a string (defensive against unexpected types)
+ */
+function ensureString(value: unknown): string {
+  if (typeof value === "string") {
+    return value;
+  }
+  if (value === null || value === undefined) {
+    return "";
+  }
+  // If it's an object, try to extract text content or stringify it
+  if (typeof value === "object") {
+    // Handle potential content array format
+    if (Array.isArray(value)) {
+      return value
+        .filter((item): item is { type: string; text: string } =>
+          item && typeof item === "object" && item.type === "text" && typeof item.text === "string"
+        )
+        .map((item) => item.text)
+        .join("");
+    }
+    // Last resort: stringify the object
+    return JSON.stringify(value);
+  }
+  return String(value);
+}
+
 /**
  * Convert Claude CLI result to OpenAI non-streaming response
  */
@@ -74,6 +101,9 @@ export function cliResultToOpenai(
     ? Object.keys(result.modelUsage)[0]
     : "claude-sonnet-4";
 
+  // Ensure content is always a string to prevent [object Object] issues
+  const content = ensureString(result.result);
+
   return {
     id: `chatcmpl-${requestId}`,
     object: "chat.completion",
@@ -84,7 +114,7 @@ export function cliResultToOpenai(
         index: 0,
         message: {
           role: "assistant",
-          content: result.result,
+          content,
         },
         finish_reason: "stop",
       },

src/adapter/openai-to-cli.ts

@@ -46,6 +46,44 @@ export function extractModel(model: string): ClaudeModel {
   return "opus";
 }
 
+/**
+ * Extract text from message content (handles both string and array formats)
+ *
+ * OpenAI API allows content to be:
+ * - A string: "Hello"
+ * - An array of content parts: [{"type": "text", "text": "Hello"}]
+ */
+function extractContentText(content: unknown): string {
+  // Simple string content
+  if (typeof content === "string") {
+    return content;
+  }
+
+  // Array of content parts (multi-modal format)
+  if (Array.isArray(content)) {
+    return content
+      .filter((part): part is { type: string; text: string } =>
+        part && typeof part === "object" && part.type === "text" && typeof part.text === "string"
+      )
+      .map((part) => part.text)
+      .join("");
+  }
+
+  // Null/undefined
+  if (content === null || content === undefined) {
+    return "";
+  }
+
+  // Unknown object - try to stringify as last resort
+  if (typeof content === "object") {
+    console.error("[extractContentText] Unexpected object content:", JSON.stringify(content).slice(0, 200));
+    return JSON.stringify(content);
+  }
+
+  // Other types - convert to string
+  return String(content);
+}
+
 /**
  * Convert OpenAI messages array to a single prompt string for Claude CLI
  *
@@ -56,20 +94,22 @@ export function messagesToPrompt(messages: OpenAIChatRequest["messages"]): strin
   const parts: string[] = [];
 
   for (const msg of messages) {
+    const textContent = extractContentText(msg.content);
+
     switch (msg.role) {
       case "system":
         // System messages become context instructions
-        parts.push(`<system>\n${msg.content}\n</system>\n`);
+        parts.push(`<system>\n${textContent}\n</system>\n`);
         break;
 
       case "user":
         // User messages are the main prompt
-        parts.push(msg.content);
+        parts.push(textContent);
         break;
 
       case "assistant":
         // Previous assistant responses for context
-        parts.push(`<previous_response>\n${msg.content}\n</previous_response>\n`);
+        parts.push(`<previous_response>\n${textContent}\n</previous_response>\n`);
         break;
     }
   }

src/server/routes.ts

@@ -28,6 +28,21 @@ export async function handleChatCompletions(
   const body = req.body as OpenAIChatRequest;
   const stream = body.stream === true;
 
+  // Debug: Log incoming request for diagnostics
+  console.error(`[Request ${requestId}] Incoming request:`, JSON.stringify({
+    model: body.model,
+    stream: body.stream,
+    messageCount: body.messages?.length,
+    messages: body.messages?.map((m, i) => ({
+      index: i,
+      role: m.role,
+      contentType: typeof m.content,
+      contentPreview: typeof m.content === 'string'
+        ? m.content.slice(0, 100)
+        : JSON.stringify(m.content).slice(0, 100)
+    }))
+  }));
+
   try {
     // Validate request
     if (!body.messages || !Array.isArray(body.messages) || body.messages.length === 0) {
@@ -109,7 +124,9 @@ async function handleStreamingResponse(
 
     // Handle streaming content deltas
     subprocess.on("content_delta", (event: ClaudeCliStreamEvent) => {
-      const text = event.event.delta?.text || "";
+      // Defensive: ensure text is always a string
+      const rawText = event.event.delta?.text;
+      const text = typeof rawText === "string" ? rawText : (rawText ? String(rawText) : "");
       if (text && !res.writableEnded) {
         const chunk = {
           id: `chatcmpl-${requestId}`,
@@ -135,8 +152,12 @@ async function handleStreamingResponse(
       lastModel = message.message.model;
     });
 
-    subprocess.on("result", (_result: ClaudeCliResult) => {
+    subprocess.on("result", (result: ClaudeCliResult) => {
       isComplete = true;
+      // Debug: log result type for diagnostics
+      if (typeof result.result !== "string") {
+        console.error(`[Streaming] WARNING: result.result is not a string, type: ${typeof result.result}`);
+      }
       if (!res.writableEnded) {
         // Send final done chunk with finish_reason
         const doneChunk = createDoneChunk(requestId, lastModel);

src/types/openai.ts

@@ -3,9 +3,18 @@
  * Used for Clawdbot integration
  */
 
+// Content can be a string or an array of content parts (multi-modal)
+export interface OpenAIContentPart {
+  type: "text" | "image_url";
+  text?: string;
+  image_url?: { url: string };
+}
+
+export type OpenAIMessageContent = string | OpenAIContentPart[];
+
 export interface OpenAIChatMessage {
   role: "system" | "user" | "assistant";
-  content: string;
+  content: OpenAIMessageContent;
 }
 
 export interface OpenAIChatRequest {