diff --git a/astrbot/dashboard/routes/open_api.py b/astrbot/dashboard/routes/open_api.py
index c1b290ae15..b3c2bc1a6d 100644
--- a/astrbot/dashboard/routes/open_api.py
+++ b/astrbot/dashboard/routes/open_api.py
@@ -40,7 +40,10 @@ def __init__(
             "/v1/chat": ("POST", self.chat_send),
             "/v1/chat/sessions": ("GET", self.get_chat_sessions),
             "/v1/configs": ("GET", self.get_chat_configs),
-            "/v1/file": ("POST", self.upload_file),
+            "/v1/file": [
+                ("POST", self.upload_file),
+                ("GET", self.get_file),
+            ],
             "/v1/im/message": ("POST", self.send_message),
             "/v1/im/bots": ("GET", self.get_bots),
         }
@@ -455,10 +458,7 @@ async def _handle_chat_ws_send(self, post_data: dict) -> None:
                 if msg_type == "end":
                     break
                 if (streaming and msg_type == "complete") or not streaming:
-                    if chain_type in (
-                        "tool_call",
-                        "tool_call_result",
-                    ):
+                    if chain_type in ("tool_call", "tool_call_result"):
                         continue
                     try:
                         refs = self.chat_route._extract_web_search_refs(
@@ -540,6 +540,9 @@ async def chat_ws(self) -> None:
     async def upload_file(self):
         return await self.chat_route.post_file()
 
+    async def get_file(self):
+        return await self.chat_route.get_attachment()
+
     async def get_chat_sessions(self):
         username, username_err = self._resolve_open_username(
             request.args.get("username")
diff --git a/docs/public/openapi.json b/docs/public/openapi.json
index 2fadecbc01..c767f5b31e 100644
--- a/docs/public/openapi.json
+++ b/docs/public/openapi.json
@@ -97,6 +97,48 @@
           "403": {
             "$ref": "#/components/responses/Forbidden"
           }
+          }
+      },
+      "get": {
+        "tags": [
+          "Open API"
+        ],
+        "summary": "Get attachment file",
+        "description": "Get an uploaded attachment file by attachment_id.",
+        "security": [
+          {
+            "ApiKeyHeader": []
+          }
+        ],
+        "parameters": [
+          {
+            "name": "attachment_id",
+            "in": "query",
+            "required": true,
+            "schema": {
+              "type": "string"
+            },
+            "description": "Attachment ID returned by POST /api/v1/file."
+          }
+        ],
+        "responses": {
+          "200": {
+            "description": "OK",
+            "content": {
+              "application/octet-stream": {
+                "schema": {
+                  "type": "string",
+                  "format": "binary"
+                }
+              }
+            }
+          },
+          "401": {
+            "$ref": "#/components/responses/Unauthorized"
+          },
+          "403": {
+            "$ref": "#/components/responses/Forbidden"
+          }
         }
       }
     },
diff --git a/openapi.json b/openapi.json
deleted file mode 100644
index 2fadecbc01..0000000000
--- a/openapi.json
+++ /dev/null
@@ -1,685 +0,0 @@
-{
-  "openapi": "3.1.0",
-  "info": {
-    "title": "AstrBot Open API",
-    "version": "1.0.0",
-    "description": "Developer HTTP APIs for AstrBot. Use API Key authentication for /api/v1/* endpoints."
-  },
-  "servers": [
-    {
-      "url": "http://localhost:6185"
-    }
-  ],
-  "tags": [
-    {
-      "name": "Open API",
-      "description": "Developer APIs authenticated by API Key"
-    }
-  ],
-  "paths": {
-    "/api/v1/im/bots": {
-      "get": {
-        "tags": [
-          "Open API"
-        ],
-        "summary": "List bot IDs",
-        "description": "Returns configured bot/platform IDs.",
-        "security": [
-          {
-            "ApiKeyHeader": []
-          }
-        ],
-        "responses": {
-          "200": {
-            "description": "OK",
-            "content": {
-              "application/json": {
-                "schema": {
-                  "$ref": "#/components/schemas/ApiResponseBotList"
-                }
-              }
-            }
-          },
-          "401": {
-            "$ref": "#/components/responses/Unauthorized"
-          },
-          "403": {
-            "$ref": "#/components/responses/Forbidden"
-          }
-        }
-      }
-    },
-    "/api/v1/file": {
-      "post": {
-        "tags": [
-          "Open API"
-        ],
-        "summary": "Upload attachment file",
-        "description": "Upload a file and get attachment_id for later use in chat/message APIs.",
-        "security": [
-          {
-            "ApiKeyHeader": []
-          }
-        ],
-        "requestBody": {
-          "required": true,
-          "content": {
-            "multipart/form-data": {
-              "schema": {
-                "type": "object",
-                "required": [
-                  "file"
-                ],
-                "properties": {
-                  "file": {
-                    "type": "string",
-                    "format": "binary"
-                  }
-                }
-              }
-            }
-          }
-        },
-        "responses": {
-          "200": {
-            "description": "OK",
-            "content": {
-              "application/json": {
-                "schema": {
-                  "$ref": "#/components/schemas/ApiResponseUpload"
-                }
-              }
-            }
-          },
-          "401": {
-            "$ref": "#/components/responses/Unauthorized"
-          },
-          "403": {
-            "$ref": "#/components/responses/Forbidden"
-          }
-        }
-      }
-    },
-    "/api/v1/chat": {
-      "post": {
-        "tags": [
-          "Open API"
-        ],
-        "summary": "Send chat message (SSE)",
-        "description": "Send message to AstrBot chat pipeline and receive streaming SSE response. Reuses /api/chat/send behavior. If session_id/conversation_id is omitted, server will create a new UUID session_id.",
-        "security": [
-          {
-            "ApiKeyHeader": []
-          }
-        ],
-        "requestBody": {
-          "required": true,
-          "content": {
-            "application/json": {
-              "schema": {
-                "$ref": "#/components/schemas/ChatSendRequest"
-              },
-              "examples": {
-                "plain": {
-                  "value": {
-                    "message": "Hello",
-                    "username": "alice",
-                    "session_id": "my_session_001",
-                    "enable_streaming": true
-                  }
-                },
-                "multipartMessage": {
-                  "value": {
-                    "message": [
-                      {
-                        "type": "plain",
-                        "text": "Please analyze this file"
-                      },
-                      {
-                        "type": "file",
-                        "attachment_id": "9a2f8c72-e7af-4c0e-b352-111111111111"
-                      }
-                    ],
-                    "username": "alice",
-                    "session_id": "my_session_001",
-                    "selected_provider": "openai_chat_completion",
-                    "selected_model": "gpt-4.1-mini",
-                    "enable_streaming": true
-                  }
-                },
-                "withConfig": {
-                  "value": {
-                    "message": "Use a specific config for this session",
-                    "username": "alice",
-                    "session_id": "my_session_001",
-                    "config_id": "default",
-                    "enable_streaming": true
-                  }
-                },
-                "autoSessionWithUsername": {
-                  "value": {
-                    "message": "hello",
-                    "username": "alice",
-                    "enable_streaming": true
-                  }
-                }
-              }
-            }
-          }
-        },
-        "responses": {
-          "200": {
-            "description": "SSE stream",
-            "content": {
-              "text/event-stream": {
-                "schema": {
-                  "type": "string"
-                }
-              }
-            }
-          },
-          "401": {
-            "$ref": "#/components/responses/Unauthorized"
-          },
-          "403": {
-            "$ref": "#/components/responses/Forbidden"
-          }
-        }
-      }
-    },
-    "/api/v1/chat/sessions": {
-      "get": {
-        "tags": [
-          "Open API"
-        ],
-        "summary": "List chat sessions with pagination",
-        "description": "List chat sessions for the specified username.",
-        "security": [
-          {
-            "ApiKeyHeader": []
-          }
-        ],
-        "parameters": [
-          {
-            "name": "page",
-            "in": "query",
-            "schema": {
-              "type": "integer",
-              "default": 1,
-              "minimum": 1
-            }
-          },
-          {
-            "name": "page_size",
-            "in": "query",
-            "schema": {
-              "type": "integer",
-              "default": 20,
-              "minimum": 1,
-              "maximum": 100
-            }
-          },
-          {
-            "name": "platform_id",
-            "in": "query",
-            "schema": {
-              "type": "string"
-            },
-            "description": "Optional platform filter"
-          },
-          {
-            "name": "username",
-            "in": "query",
-            "required": true,
-            "schema": {
-              "type": "string"
-            },
-            "description": "Target username."
-          }
-        ],
-        "responses": {
-          "200": {
-            "description": "OK",
-            "content": {
-              "application/json": {
-                "schema": {
-                  "$ref": "#/components/schemas/ApiResponseChatSessions"
-                }
-              }
-            }
-          },
-          "401": {
-            "$ref": "#/components/responses/Unauthorized"
-          },
-          "403": {
-            "$ref": "#/components/responses/Forbidden"
-          }
-        }
-      }
-    },
-    "/api/v1/im/message": {
-      "post": {
-        "tags": [
-          "Open API"
-        ],
-        "summary": "Send proactive message to a platform bot",
-        "description": "Send message directly to platform bot by umo + message chain payload.",
-        "security": [
-          {
-            "ApiKeyHeader": []
-          }
-        ],
-        "requestBody": {
-          "required": true,
-          "content": {
-            "application/json": {
-              "schema": {
-                "$ref": "#/components/schemas/SendMessageRequest"
-              },
-              "examples": {
-                "plain": {
-                  "value": {
-                    "umo": "webchat:FriendMessage:openapi_probe",
-                    "message": "ping from api key"
-                  }
-                },
-                "chain": {
-                  "value": {
-                    "umo": "webchat:FriendMessage:openapi_probe",
-                    "message": [
-                      {
-                        "type": "plain",
-                        "text": "hello"
-                      },
-                      {
-                        "type": "image",
-                        "attachment_id": "9a2f8c72-e7af-4c0e-b352-111111111111"
-                      }
-                    ]
-                  }
-                }
-              }
-            }
-          }
-        },
-        "responses": {
-          "200": {
-            "description": "OK",
-            "content": {
-              "application/json": {
-                "schema": {
-                  "$ref": "#/components/schemas/ApiResponseEmpty"
-                }
-              }
-            }
-          },
-          "401": {
-            "$ref": "#/components/responses/Unauthorized"
-          },
-          "403": {
-            "$ref": "#/components/responses/Forbidden"
-          }
-        }
-      }
-    },
-    "/api/v1/configs": {
-      "get": {
-        "tags": [
-          "Open API"
-        ],
-        "summary": "List available chat config files",
-        "description": "Returns all available AstrBot config files that can be selected by Chat API using config_id/config_name.",
-        "security": [
-          {
-            "ApiKeyHeader": []
-          }
-        ],
-        "responses": {
-          "200": {
-            "description": "OK",
-            "content": {
-              "application/json": {
-                "schema": {
-                  "$ref": "#/components/schemas/ApiResponseChatConfigList"
-                }
-              }
-            }
-          },
-          "401": {
-            "$ref": "#/components/responses/Unauthorized"
-          },
-          "403": {
-            "$ref": "#/components/responses/Forbidden"
-          }
-        }
-      }
-    }
-  },
-  "components": {
-    "securitySchemes": {
-      "ApiKeyHeader": {
-        "type": "apiKey",
-        "in": "header",
-        "name": "X-API-Key",
-        "description": "Open API key. Authorization: Bearer <api_key> is also accepted."
-      }
-    },
-    "responses": {
-      "Unauthorized": {
-        "description": "Unauthorized"
-      },
-      "Forbidden": {
-        "description": "Forbidden"
-      }
-    },
-    "schemas": {
-      "ApiResponseEmpty": {
-        "type": "object",
-        "properties": {
-          "status": {
-            "type": "string",
-            "example": "ok"
-          },
-          "message": {
-            "type": [
-              "string",
-              "null"
-            ]
-          },
-          "data": {
-            "type": "object",
-            "additionalProperties": true
-          }
-        }
-      },
-      "ApiResponseBotList": {
-        "type": "object",
-        "properties": {
-          "status": {
-            "type": "string",
-            "example": "ok"
-          },
-          "message": {
-            "type": [
-              "string",
-              "null"
-            ]
-          },
-          "data": {
-            "type": "object",
-            "properties": {
-              "bot_ids": {
-                "type": "array",
-                "items": {
-                  "type": "string"
-                }
-              }
-            }
-          }
-        }
-      },
-      "ApiResponseUpload": {
-        "type": "object",
-        "properties": {
-          "status": {
-            "type": "string",
-            "example": "ok"
-          },
-          "message": {
-            "type": [
-              "string",
-              "null"
-            ]
-          },
-          "data": {
-            "type": "object",
-            "properties": {
-              "attachment_id": {
-                "type": "string"
-              },
-              "filename": {
-                "type": "string"
-              },
-              "type": {
-                "type": "string"
-              }
-            }
-          }
-        }
-      },
-      "ApiResponseChatSessions": {
-        "type": "object",
-        "properties": {
-          "status": {
-            "type": "string",
-            "example": "ok"
-          },
-          "message": {
-            "type": [
-              "string",
-              "null"
-            ]
-          },
-          "data": {
-            "type": "object",
-            "properties": {
-              "sessions": {
-                "type": "array",
-                "items": {
-                  "$ref": "#/components/schemas/ChatSessionItem"
-                }
-              },
-              "page": {
-                "type": "integer"
-              },
-              "page_size": {
-                "type": "integer"
-              },
-              "total": {
-                "type": "integer"
-              }
-            }
-          }
-        }
-      },
-      "ChatSessionItem": {
-        "type": "object",
-        "properties": {
-          "session_id": {
-            "type": "string"
-          },
-          "platform_id": {
-            "type": "string"
-          },
-          "creator": {
-            "type": "string"
-          },
-          "display_name": {
-            "type": [
-              "string",
-              "null"
-            ]
-          },
-          "is_group": {
-            "type": "integer"
-          },
-          "created_at": {
-            "type": "string",
-            "format": "date-time"
-          },
-          "updated_at": {
-            "type": "string",
-            "format": "date-time"
-          }
-        }
-      },
-      "MessagePart": {
-        "type": "object",
-        "properties": {
-          "type": {
-            "type": "string",
-            "enum": [
-              "plain",
-              "reply",
-              "image",
-              "record",
-              "file",
-              "video"
-            ]
-          },
-          "text": {
-            "type": "string"
-          },
-          "message_id": {
-            "type": [
-              "string",
-              "integer"
-            ]
-          },
-          "selected_text": {
-            "type": "string"
-          },
-          "attachment_id": {
-            "type": "string"
-          },
-          "filename": {
-            "type": "string"
-          },
-          "path": {
-            "type": "string"
-          }
-        },
-        "required": [
-          "type"
-        ]
-      },
-      "ChatSendRequest": {
-        "type": "object",
-        "required": [
-          "message",
-          "username"
-        ],
-        "properties": {
-          "message": {
-            "oneOf": [
-              {
-                "type": "string"
-              },
-              {
-                "type": "array",
-                "items": {
-                  "$ref": "#/components/schemas/MessagePart"
-                }
-              }
-            ]
-          },
-          "session_id": {
-            "type": "string",
-            "description": "Optional chat session ID. If omitted (and conversation_id is also omitted), server creates a UUID automatically."
-          },
-          "conversation_id": {
-            "type": "string",
-            "description": "Alias of session_id."
-          },
-          "username": {
-            "type": "string",
-            "description": "Target username."
-          },
-          "selected_provider": {
-            "type": "string"
-          },
-          "selected_model": {
-            "type": "string"
-          },
-          "enable_streaming": {
-            "type": "boolean",
-            "default": true
-          },
-          "config_id": {
-            "type": "string",
-            "description": "Optional AstrBot config file ID. If provided, the chat session will use this config file. Use \"default\" to reset to default config."
-          },
-          "config_name": {
-            "type": "string",
-            "description": "Optional AstrBot config file name. Used only when config_id is not provided."
-          }
-        }
-      },
-      "SendMessageRequest": {
-        "type": "object",
-        "required": [
-          "umo",
-          "message"
-        ],
-        "properties": {
-          "umo": {
-            "type": "string",
-            "description": "Unified message origin. Format: platform:message_type:session_id"
-          },
-          "message": {
-            "oneOf": [
-              {
-                "type": "string"
-              },
-              {
-                "type": "array",
-                "items": {
-                  "$ref": "#/components/schemas/MessagePart"
-                }
-              }
-            ]
-          }
-        }
-      },
-      "ChatConfigFile": {
-        "type": "object",
-        "properties": {
-          "id": {
-            "type": "string"
-          },
-          "name": {
-            "type": "string"
-          },
-          "path": {
-            "type": "string"
-          },
-          "is_default": {
-            "type": "boolean"
-          }
-        },
-        "required": [
-          "id",
-          "name",
-          "path",
-          "is_default"
-        ]
-      },
-      "ApiResponseChatConfigList": {
-        "type": "object",
-        "properties": {
-          "status": {
-            "type": "string",
-            "example": "ok"
-          },
-          "message": {
-            "type": [
-              "string",
-              "null"
-            ]
-          },
-          "data": {
-            "type": "object",
-            "properties": {
-              "configs": {
-                "type": "array",
-                "items": {
-                  "$ref": "#/components/schemas/ChatConfigFile"
-                }
-              }
-            }
-          }
-        }
-      }
-    }
-  }
-}