fix(webchat): support image-only sends

CHANGELOG.md

@@ -34,6 +34,9 @@ Status: unreleased.
 - Slack: clear ack reaction after streamed replies. (#2044) Thanks @fancyboi999.
 - macOS: keep custom SSH usernames in remote target. (#2046) Thanks @algal.
 
+### Fixes
+- Web UI: improve WebChat image paste previews and allow image-only sends. (#1925) Thanks @smartprogrammer93.
+
 ## 2026.1.24-3
 
 ### Fixes

src/gateway/protocol/schema/logs-chat.ts

@@ -35,7 +35,7 @@ export const ChatHistoryParamsSchema = Type.Object(
 export const ChatSendParamsSchema = Type.Object(
   {
     sessionKey: NonEmptyString,
-    message: NonEmptyString,
+    message: Type.String(),
     thinking: Type.Optional(Type.String()),
     deliver: Type.Optional(Type.Boolean()),
     attachments: Type.Optional(Type.Array(Type.Unknown())),

src/gateway/server-methods/chat.ts

@@ -338,6 +338,15 @@ export const chatHandlers: GatewayRequestHandlers = {
                 : undefined,
         }))
         .filter((a) => a.content) ?? [];
+    const rawMessage = p.message.trim();
+    if (!rawMessage && normalizedAttachments.length === 0) {
+      respond(
+        false,
+        undefined,
+        errorShape(ErrorCodes.INVALID_REQUEST, "message or attachment required"),
+      );
+      return;
+    }
     let parsedMessage = p.message;
     let parsedImages: ChatImageContent[] = [];
     if (normalizedAttachments.length > 0) {

src/gateway/server.chat.gateway-server-chat.e2e.test.ts

@@ -208,6 +208,39 @@ describe("gateway server chat", () => {
         | undefined;
       expect(imgOpts?.images).toEqual([{ type: "image", data: pngB64, mimeType: "image/png" }]);
 
+      const callsBeforeImageOnly = spy.mock.calls.length;
+      const reqIdOnly = "chat-img-only";
+      ws.send(
+        JSON.stringify({
+          type: "req",
+          id: reqIdOnly,
+          method: "chat.send",
+          params: {
+            sessionKey: "main",
+            message: "",
+            idempotencyKey: "idem-img-only",
+            attachments: [
+              {
+                type: "image",
+                mimeType: "image/png",
+                fileName: "dot.png",
+                content: `data:image/png;base64,${pngB64}`,
+              },
+            ],
+          },
+        }),
+      );
+
+      const imgOnlyRes = await onceMessage(ws, (o) => o.type === "res" && o.id === reqIdOnly, 8000);
+      expect(imgOnlyRes.ok).toBe(true);
+      expect(imgOnlyRes.payload?.runId).toBeDefined();
+
+      await waitFor(() => spy.mock.calls.length > callsBeforeImageOnly, 8000);
+      const imgOnlyOpts = spy.mock.calls.at(-1)?.[1] as
+        | { images?: Array<{ type: string; data: string; mimeType: string }> }
+        | undefined;
+      expect(imgOnlyOpts?.images).toEqual([{ type: "image", data: pngB64, mimeType: "image/png" }]);
+
       const historyDir = await fs.mkdtemp(path.join(os.tmpdir(), "clawdbot-gw-"));
       tempDirs.push(historyDir);
       testState.sessionStorePath = path.join(historyDir, "sessions.json");

ui/src/ui/app-chat.ts

@@ -1,4 +1,4 @@
-import { abortChatRun, loadChatHistory, sendChatMessage, type ChatAttachment } from "./controllers/chat";
+import { abortChatRun, loadChatHistory, sendChatMessage } from "./controllers/chat";
 import { loadSessions } from "./controllers/sessions";
 import { generateUUID } from "./uuid";
 import { resetToolStream } from "./app-tool-stream";
@@ -8,12 +8,13 @@ import { normalizeBasePath } from "./navigation";
 import type { GatewayHelloOk } from "./gateway";
 import { parseAgentSessionKey } from "../../../src/sessions/session-key-utils.js";
 import type { ClawdbotApp } from "./app";
+import type { ChatAttachment, ChatQueueItem } from "./ui-types";
 
 type ChatHost = {
   connected: boolean;
   chatMessage: string;
   chatAttachments: ChatAttachment[];
-  chatQueue: Array<{ id: string; text: string; createdAt: number }>;
+  chatQueue: ChatQueueItem[];
   chatRunId: string | null;
   chatSending: boolean;
   sessionKey: string;
@@ -46,15 +47,17 @@ export async function handleAbortChat(host: ChatHost) {
   await abortChatRun(host as unknown as ClawdbotApp);
 }
 
-function enqueueChatMessage(host: ChatHost, text: string) {
+function enqueueChatMessage(host: ChatHost, text: string, attachments?: ChatAttachment[]) {
   const trimmed = text.trim();
-  if (!trimmed) return;
+  const hasAttachments = Boolean(attachments && attachments.length > 0);
+  if (!trimmed && !hasAttachments) return;
   host.chatQueue = [
     ...host.chatQueue,
     {
       id: generateUUID(),
       text: trimmed,
       createdAt: Date.now(),
+      attachments: hasAttachments ? attachments?.map((att) => ({ ...att })) : undefined,
     },
   ];
 }
@@ -62,19 +65,31 @@ function enqueueChatMessage(host: ChatHost, text: string) {
 async function sendChatMessageNow(
   host: ChatHost,
   message: string,
-  opts?: { previousDraft?: string; restoreDraft?: boolean; attachments?: ChatAttachment[] },
+  opts?: {
+    previousDraft?: string;
+    restoreDraft?: boolean;
+    attachments?: ChatAttachment[];
+    previousAttachments?: ChatAttachment[];
+    restoreAttachments?: boolean;
+  },
 ) {
   resetToolStream(host as unknown as Parameters<typeof resetToolStream>[0]);
   const ok = await sendChatMessage(host as unknown as ClawdbotApp, message, opts?.attachments);
   if (!ok && opts?.previousDraft != null) {
     host.chatMessage = opts.previousDraft;
   }
+  if (!ok && opts?.previousAttachments) {
+    host.chatAttachments = opts.previousAttachments;
+  }
   if (ok) {
     setLastActiveSessionKey(host as unknown as Parameters<typeof setLastActiveSessionKey>[0], host.sessionKey);
   }
   if (ok && opts?.restoreDraft && opts.previousDraft?.trim()) {
     host.chatMessage = opts.previousDraft;
   }
+  if (ok && opts?.restoreAttachments && opts.previousAttachments?.length) {
+    host.chatAttachments = opts.previousAttachments;
+  }
   scheduleChatScroll(host as unknown as Parameters<typeof scheduleChatScroll>[0]);
   if (ok && !host.chatRunId) {
     void flushChatQueue(host);
@@ -87,7 +102,7 @@ async function flushChatQueue(host: ChatHost) {
   const [next, ...rest] = host.chatQueue;
   if (!next) return;
   host.chatQueue = rest;
-  const ok = await sendChatMessageNow(host, next.text);
+  const ok = await sendChatMessageNow(host, next.text, { attachments: next.attachments });
   if (!ok) {
     host.chatQueue = [next, ...host.chatQueue];
   }
@@ -106,7 +121,8 @@ export async function handleSendChat(
   const previousDraft = host.chatMessage;
   const message = (messageOverride ?? host.chatMessage).trim();
   const attachments = host.chatAttachments ?? [];
-  const hasAttachments = attachments.length > 0;
+  const attachmentsToSend = messageOverride == null ? attachments : [];
+  const hasAttachments = attachmentsToSend.length > 0;
 
   // Allow sending with just attachments (no message text required)
   if (!message && !hasAttachments) return;
@@ -123,14 +139,16 @@ export async function handleSendChat(
   }
 
   if (isChatBusy(host)) {
-    enqueueChatMessage(host, message);
+    enqueueChatMessage(host, message, attachmentsToSend);
     return;
   }
 
   await sendChatMessageNow(host, message, {
     previousDraft: messageOverride == null ? previousDraft : undefined,
     restoreDraft: Boolean(messageOverride && opts?.restoreDraft),
-    attachments: hasAttachments ? attachments : undefined,
+    attachments: hasAttachments ? attachmentsToSend : undefined,
+    previousAttachments: messageOverride == null ? attachments : undefined,
+    restoreAttachments: Boolean(messageOverride && opts?.restoreDraft),
   });
 }
 

ui/src/ui/app-render.ts

@@ -431,6 +431,7 @@ export function renderApp(state: AppViewState) {
               onSessionKeyChange: (next) => {
                 state.sessionKey = next;
                 state.chatMessage = "";
+                state.chatAttachments = [];
                 state.chatStream = null;
                 state.chatStreamStartedAt = null;
                 state.chatRunId = null;

ui/src/ui/app-view-state.ts

@@ -19,7 +19,7 @@ import type {
   SkillStatusReport,
   StatusSummary,
 } from "./types";
-import type { ChatQueueItem, CronFormState } from "./ui-types";
+import type { ChatAttachment, ChatQueueItem, CronFormState } from "./ui-types";
 import type { EventLogEntry } from "./app-events";
 import type { SkillMessage } from "./controllers/skills";
 import type {
@@ -49,6 +49,7 @@ export type AppViewState = {
   chatLoading: boolean;
   chatSending: boolean;
   chatMessage: string;
+  chatAttachments: ChatAttachment[];
   chatMessages: unknown[];
   chatToolMessages: unknown[];
   chatStream: string | null;

ui/src/ui/app.ts

@@ -24,7 +24,7 @@ import type {
   StatusSummary,
   NostrProfile,
 } from "./types";
-import { type ChatQueueItem, type CronFormState } from "./ui-types";
+import { type ChatAttachment, type ChatQueueItem, type CronFormState } from "./ui-types";
 import type { EventLogEntry } from "./app-events";
 import { DEFAULT_CRON_FORM, DEFAULT_LOG_LEVEL_FILTERS } from "./app-defaults";
 import type {
@@ -129,7 +129,7 @@ export class ClawdbotApp extends LitElement {
   @state() chatAvatarUrl: string | null = null;
   @state() chatThinkingLevel: string | null = null;
   @state() chatQueue: ChatQueueItem[] = [];
-  @state() chatAttachments: Array<{ id: string; dataUrl: string; mimeType: string }> = [];
+  @state() chatAttachments: ChatAttachment[] = [];
   // Sidebar state for tool output viewing
   @state() sidebarOpen = false;
   @state() sidebarContent: string | null = null;

ui/src/ui/controllers/chat.ts

@@ -1,12 +1,7 @@
 import { extractText } from "../chat/message-extract";
 import type { GatewayBrowserClient } from "../gateway";
 import { generateUUID } from "../uuid";
-
+import type { ChatAttachment } from "../ui-types";
-export type ChatAttachment = {
-  id: string;
-  dataUrl: string;
-  mimeType: string;
-};
 
 export type ChatState = {
   client: GatewayBrowserClient | null;

ui/src/ui/ui-types.ts

@@ -1,7 +1,14 @@
+export type ChatAttachment = {
+  id: string;
+  dataUrl: string;
+  mimeType: string;
+};
+
 export type ChatQueueItem = {
   id: string;
   text: string;
   createdAt: number;
+  attachments?: ChatAttachment[];
 };
 
 export const CRON_CHANNEL_LAST = "last";

ui/src/ui/views/chat.ts

@@ -1,7 +1,7 @@
 import { html, nothing } from "lit";
 import { repeat } from "lit/directives/repeat.js";
 import type { SessionsListResult } from "../types";
-import type { ChatQueueItem } from "../ui-types";
+import type { ChatAttachment, ChatQueueItem } from "../ui-types";
 import type { ChatItem, MessageGroup } from "../types/chat-types";
 import { icons } from "../icons";
 import {
@@ -22,12 +22,6 @@ export type CompactionIndicatorStatus = {
   completedAt: number | null;
 };
 
-export type ChatAttachment = {
-  id: string;
-  dataUrl: string;
-  mimeType: string;
-};
-
 export type ChatProps = {
   sessionKey: string;
   onSessionKeyChange: (next: string) => void;
@@ -305,7 +299,12 @@ export function renderChat(props: ChatProps) {
                 ${props.queue.map(
                   (item) => html`
                     <div class="chat-queue__item">
-                      <div class="chat-queue__text">${item.text}</div>
+                      <div class="chat-queue__text">
+                        ${item.text ||
+                        (item.attachments?.length
+                          ? `Image (${item.attachments.length})`
+                          : "")}
+                      </div>
                       <button
                         class="btn chat-queue__remove"
                         type="button"