Support multimodal images in local chat agent

apps/device-host-agent/host_agent/conversation.py

@@ -38,7 +38,7 @@ class ConversationAgent:
         self.max_rounds = max_rounds
         self._client: Any | None = None
 
-    def chat(self, messages: list[dict[str, str]]) -> ChatResult:
+    def chat(self, messages: list[dict[str, Any]]) -> ChatResult:
         if self.config.provider not in {"openai", "openai_compatible"}:
             raise RuntimeError(
                 "conversation chat currently requires an OpenAI-compatible provider"
@@ -54,7 +54,7 @@ class ConversationAgent:
                     "completed unless the tool result confirms it."
                 ),
             },
-            *messages,
+            *[_normalize_message(message) for message in messages],
         ]
         calls = 0
         for _ in range(self.max_rounds):
@@ -142,3 +142,36 @@ def _message_dict(message: Any) -> dict[str, Any]:
         for call in calls
     ]
     return result
+
+
+def _normalize_message(message: dict[str, Any]) -> dict[str, Any]:
+    """Accept OpenAI text/image content blocks and a compact image_base64 form."""
+    role = message.get("role")
+    content = message.get("content")
+    if isinstance(content, str):
+        return {"role": role, "content": content}
+    if isinstance(content, list):
+        blocks: list[dict[str, Any]] = []
+        for block in content:
+            if not isinstance(block, dict):
+                continue
+            if block.get("type") == "text" and isinstance(block.get("text"), str):
+                blocks.append({"type": "text", "text": block["text"]})
+            elif block.get("type") == "image_url":
+                image_url = block.get("image_url")
+                if isinstance(image_url, str):
+                    image_url = {"url": image_url}
+                if isinstance(image_url, dict) and isinstance(image_url.get("url"), str):
+                    blocks.append({"type": "image_url", "image_url": {"url": image_url["url"]}})
+        if blocks:
+            return {"role": role, "content": blocks}
+    image = message.get("image_base64")
+    if isinstance(image, str) and image:
+        mime = str(message.get("mime_type") or "image/png")
+        text = message.get("text")
+        blocks = []
+        if isinstance(text, str) and text:
+            blocks.append({"type": "text", "text": text})
+        blocks.append({"type": "image_url", "image_url": {"url": f"data:{mime};base64,{image}"}})
+        return {"role": role, "content": blocks}
+    raise ValueError("message content must be text, image blocks, or image_base64")

apps/device-host-agent/host_agent/web/app.py

@@ -429,11 +429,11 @@ def create_console_app(
         if not isinstance(raw_messages, list) or not raw_messages:
             raise HTTPException(status_code=400, detail="messages must be a non-empty list")
         messages = [
-            {"role": str(item["role"]), "content": str(item["content"])}
+            {key: value for key, value in item.items() if key in {"role", "content", "image_base64", "mime_type", "text"}}
             for item in raw_messages
             if isinstance(item, dict)
             and item.get("role") in {"user", "assistant"}
-            and isinstance(item.get("content"), str)
+            and (isinstance(item.get("content"), (str, list)) or isinstance(item.get("image_base64"), str))
         ]
         if not messages:
             raise HTTPException(status_code=400, detail="messages are invalid")