fix(Canvas): pin molecule-ai-workspace-runtime>=0.1.999 in all external workspace snippets

The molecule-mcp console script (required for heartbeat + registration)

was added in v0.1.999. Without this pin, users with older versions get

silent failures - MCP starts but workspace shows OFFLINE.

canvas/src/components/mobile/MobileChat.tsx

@@ -5,22 +5,27 @@
 // that the desktop ChatTab uses, but with a slimmer surface: no
 // attachments, no A2A topology overlay, no conversation tracing.
 
-import { useEffect, useRef, useState } from "react";
+import { useCallback, useEffect, useRef, useState } from "react";
 import ReactMarkdown from "react-markdown";
 import remarkGfm from "remark-gfm";
 
+import { api } from "@/lib/api";
 import { useCanvasStore } from "@/store/canvas";
-import { type ChatAttachment, type ChatMessage, createMessage } from "@/components/tabs/chat/types";
-import {
-  useChatHistory,
-  useChatSend,
-  useChatSocket,
-} from "@/components/tabs/chat/hooks";
+import { uploadChatFiles } from "@/components/tabs/chat/uploads";
+import type { ChatAttachment } from "@/components/tabs/chat/types";
 
 import { toMobileAgent } from "./components";
 import { MOBILE_FONT_MONO, MOBILE_FONT_SANS, usePalette } from "./palette";
 import { Icons, StatusDot, TierChip } from "./primitives";
 
+interface ChatMessage {
+  id: string;
+  role: "user" | "agent" | "system";
+  text: string;
+  ts: string;
+  attachments?: ChatAttachment[];
+}
+
 const formatStoredTimestamp = (iso: string): string => {
   const d = new Date(iso);
   if (isNaN(d.getTime())) return "";
@@ -29,6 +34,16 @@ const formatStoredTimestamp = (iso: string): string => {
 
 type SubTab = "my" | "a2a";
 
+interface A2AResponseShape {
+  result?: {
+    parts?: Array<{ kind?: string; text?: string }>;
+  };
+  error?: { message?: string };
+}
+
+const formatTime = (date: Date) =>
+  date.toLocaleTimeString([], { hour: "numeric", minute: "2-digit" });
+
 function MarkdownBubble({
   children,
   dark,
@@ -205,38 +220,24 @@ export function MobileChat({
 }) {
   const p = usePalette(dark);
   const node = useCanvasStore((s) => s.nodes.find((n) => n.id === agentId));
+  const [messages, setMessages] = useState<ChatMessage[]>([]);
   const [draft, setDraft] = useState("");
   const [tab, setTab] = useState<SubTab>("my");
+  const [sending, setSending] = useState(false);
+  const [uploading, setUploading] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+  const [historyLoading, setHistoryLoading] = useState(true);
+  const [historyError, setHistoryError] = useState<string | null>(null);
   const scrollRef = useRef<HTMLDivElement>(null);
+  // Synchronous re-entry guard. `setSending(true)` schedules a state
+  // update but doesn't flush before a second tap can fire send() — a ref
+  // mirrors the desktop ChatTab pattern (sendInFlightRef) and closes the
+  // double-send race a stale `sending` lets through.
+  const sendInFlightRef = useRef(false);
   const composerRef = useRef<HTMLTextAreaElement>(null);
   const fileInputRef = useRef<HTMLInputElement>(null);
   const [pendingFiles, setPendingFiles] = useState<File[]>([]);
 
-  const {
-    messages,
-    loading: historyLoading,
-    loadError: historyError,
-    appendMessageDeduped,
-  } = useChatHistory(agentId);
-
-  const {
-    sending,
-    uploading,
-    sendMessage,
-    error: sendError,
-    clearError,
-    releaseSendGuards,
-  } = useChatSend(agentId, {
-    getHistoryMessages: () => messages,
-    onUserMessage: appendMessageDeduped,
-    onAgentMessage: appendMessageDeduped,
-  });
-
-  useChatSocket(agentId, {
-    onAgentMessage: appendMessageDeduped,
-    onSendComplete: releaseSendGuards,
-  });
-
   // Auto-grow the textarea: reset height to 'auto' so the scrollHeight
   // shrinks when the user deletes text, then size to scrollHeight up to
   // a 5-line cap. Beyond the cap, internal scroll kicks in.
@@ -254,19 +255,73 @@ export function MobileChat({
     }
   }, [messages]);
 
-  // Consume any agent messages that arrived while history was loading.
-  const initialConsumeDoneRef = useRef(false);
+  // Load chat history on mount / agent switch.
+  const loadHistory = useCallback(async () => {
+    setHistoryLoading(true);
+    setHistoryError(null);
+    try {
+      const resp = await api.get<{
+        messages: Array<{
+          id: string;
+          role: string;
+          content: string;
+          timestamp: string;
+        }>;
+      }>(`/workspaces/${agentId}/chat-history?limit=50`);
+      const loaded = (resp.messages ?? []).map((m) => ({
+        id: m.id,
+        role: m.role as "user" | "agent" | "system",
+        text: m.content,
+        ts: formatStoredTimestamp(m.timestamp),
+      }));
+      setMessages(loaded);
+    } catch (e) {
+      setHistoryError(e instanceof Error ? e.message : "Failed to load history");
+    } finally {
+      setHistoryLoading(false);
+    }
+  }, [agentId]);
+
   useEffect(() => {
-    if (historyLoading || initialConsumeDoneRef.current) return;
-    initialConsumeDoneRef.current = true;
+    let cancelled = false;
+    loadHistory().then(() => {
+      if (cancelled) return;
+      // Consume any agent messages that arrived while history was loading.
+      const consume = useCanvasStore.getState().consumeAgentMessages;
+      const msgs = consume(agentId);
+      if (msgs.length > 0) {
+        setMessages((prev) => [
+          ...prev,
+          ...msgs.map((m) => ({
+            id: m.id,
+            role: "agent" as const,
+            text: m.content,
+            ts: formatStoredTimestamp(m.timestamp),
+          })),
+        ]);
+      }
+    });
+    return () => { cancelled = true; };
+  }, [agentId, loadHistory]);
+
+  // Consume live agent pushes while the panel is mounted.
+  const pendingAgentMsgs = useCanvasStore((s) => s.agentMessages[agentId]);
+  useEffect(() => {
+    if (!pendingAgentMsgs || pendingAgentMsgs.length === 0) return;
     const consume = useCanvasStore.getState().consumeAgentMessages;
     const msgs = consume(agentId);
-    for (const m of msgs) {
-      appendMessageDeduped(
-        createMessage("agent", m.content, m.attachments),
-      );
+    if (msgs.length > 0) {
+      setMessages((prev) => [
+        ...prev,
+        ...msgs.map((m) => ({
+          id: m.id,
+          role: "agent" as const,
+          text: m.content,
+          ts: formatStoredTimestamp(m.timestamp),
+        })),
+      ]);
     }
-  }, [historyLoading, agentId, appendMessageDeduped]);
+  }, [pendingAgentMsgs, agentId]);
 
   if (!node) {
     return (
@@ -305,11 +360,90 @@ export function MobileChat({
   const send = async () => {
     const text = draft.trim();
     if ((!text && pendingFiles.length === 0) || sending || !reachable) return;
-    clearError();
+    if (sendInFlightRef.current) return;
+    sendInFlightRef.current = true;
     setDraft("");
-    const files = pendingFiles;
-    setPendingFiles([]);
-    await sendMessage(text, files);
+    setError(null);
+    setSending(true);
+
+    let uploaded: ChatAttachment[] = [];
+    if (pendingFiles.length > 0) {
+      setUploading(true);
+      try {
+        uploaded = await uploadChatFiles(agentId, pendingFiles);
+      } catch (e) {
+        setError(e instanceof Error ? e.message : "Upload failed");
+        setSending(false);
+        setUploading(false);
+        sendInFlightRef.current = false;
+        return;
+      } finally {
+        setUploading(false);
+      }
+      setPendingFiles([]);
+    }
+
+    const myMsg: ChatMessage = {
+      id: crypto.randomUUID(),
+      role: "user",
+      text,
+      ts: formatTime(new Date()),
+      attachments: uploaded.length > 0 ? uploaded : undefined,
+    };
+    setMessages((m) => [...m, myMsg]);
+
+    try {
+      const parts: Array<
+        | { kind: "text"; text: string }
+        | {
+            kind: "file";
+            file: { name: string; mimeType?: string; uri: string; size?: number };
+          }
+      > = [];
+      if (text) parts.push({ kind: "text", text });
+      for (const att of uploaded) {
+        parts.push({
+          kind: "file",
+          file: {
+            name: att.name,
+            mimeType: att.mimeType,
+            uri: att.uri,
+            size: att.size,
+          },
+        });
+      }
+
+      const res = await api.post<A2AResponseShape>(`/workspaces/${agentId}/a2a`, {
+        method: "message/send",
+        params: {
+          message: {
+            role: "user",
+            messageId: crypto.randomUUID(),
+            parts,
+          },
+        },
+      });
+      const reply =
+        res.result?.parts?.find((part) => part.kind === "text")?.text ?? "";
+      if (reply) {
+        setMessages((m) => [
+          ...m,
+          {
+            id: crypto.randomUUID(),
+            role: "agent",
+            text: reply,
+            ts: formatTime(new Date()),
+          },
+        ]);
+      } else if (res.error?.message) {
+        setError(res.error.message);
+      }
+    } catch (e) {
+      setError(e instanceof Error ? e.message : "Failed to send");
+    } finally {
+      setSending(false);
+      sendInFlightRef.current = false;
+    }
   };
 
   return (
@@ -494,7 +628,7 @@ export function MobileChat({
                   }}
                 >
                   <MarkdownBubble dark={dark} accent={p.accent}>
-                    {m.content}
+                    {m.text}
                   </MarkdownBubble>
                   <div
                     style={{
@@ -504,13 +638,13 @@ export function MobileChat({
                       fontFamily: MOBILE_FONT_MONO,
                     }}
                   >
-                    {formatStoredTimestamp(m.timestamp)}
+                    {m.ts}
                   </div>
                 </div>
               </div>
             );
           })}
-        {sendError && (
+        {error && (
           <div
             role="alert"
             style={{
@@ -522,7 +656,7 @@ export function MobileChat({
               fontSize: 12,
             }}
           >
-            {sendError}
+            {error}
           </div>
         )}
       </div>

canvas/src/components/tabs/ChatTab.tsx

@@ -3,20 +3,18 @@
 import { useState, useRef, useEffect, useCallback, useLayoutEffect } from "react";
 import ReactMarkdown from "react-markdown";
 import remarkGfm from "remark-gfm";
+import { api } from "@/lib/api";
 import { useCanvasStore, type WorkspaceNodeData } from "@/store/canvas";
+import { useSocketEvent } from "@/hooks/useSocketEvent";
 import { type ChatMessage, type ChatAttachment, createMessage, appendMessageDeduped } from "./chat/types";
-import { downloadChatFile, isPlatformAttachment } from "./chat/uploads";
+import { uploadChatFiles, downloadChatFile, isPlatformAttachment } from "./chat/uploads";
 import { PendingAttachmentPill } from "./chat/AttachmentViews";
 import { AttachmentPreview } from "./chat/AttachmentPreview";
+import { extractFilesFromTask } from "./chat/message-parser";
 import { AgentCommsPanel } from "./chat/AgentCommsPanel";
 import { appendActivityLine } from "./chat/activityLog";
 import { runtimeDisplayName } from "@/lib/runtime-names";
 import { ConfirmDialog } from "@/components/ConfirmDialog";
-import { useChatHistory } from "./chat/hooks/useChatHistory";
-import { useChatSend } from "./chat/hooks/useChatSend";
-import { useChatSocket } from "./chat/hooks/useChatSocket";
-
-export { extractReplyText } from "./chat/hooks/useChatSend";
 
 interface Props {
   workspaceId: string;
@@ -25,6 +23,147 @@ interface Props {
 
 type ChatSubTab = "my-chat" | "agent-comms";
 
+// A2A response shape (subset). The full schema is in @a2a-js/sdk but we only
+// need parts/artifacts text + file extraction for the synchronous fallback.
+interface A2AFileRef {
+  name?: string;
+  mimeType?: string;
+  uri?: string;
+  bytes?: string;
+  size?: number;
+}
+// Outbound shape matches a2a-sdk's JSON-RPC `SendMessageRequest`
+// Pydantic union (TextPart | FilePart | DataPart). The flat
+// protobuf shape `{url, filename, mediaType}` is rejected at the
+// request boundary with `Field required` errors — keep this
+// outbound shape unless a2a-sdk migrates the JSON-RPC schema.
+interface A2APart {
+  kind: string;
+  text?: string;
+  file?: A2AFileRef;
+}
+interface A2AResponse {
+  result?: {
+    parts?: A2APart[];
+    artifacts?: Array<{ parts: A2APart[] }>;
+  };
+}
+
+// Internal-self-message filtering moved server-side in RFC #2945
+// PR-C/D — the platform's /chat-history endpoint applies the
+// IsInternalSelfMessage predicate before returning rows, so the
+// client no longer needs the local backstop on the history path.
+// The proper fix is still X-Workspace-ID header (source_id=workspace_id);
+// the platform-side prefix filter handles the residual cases.
+
+// extractReplyText pulls the agent's text reply out of an A2A response.
+// Concatenates ALL text parts (joined with "\n") rather than returning
+// just the first. Claude Code and other runtimes commonly emit multi-
+// part text replies for long content (markdown tables, code blocks),
+// and the prior "first part wins" implementation silently truncated
+// the rest — observed on a 15k-char Wave 1 brief that rendered only
+// the table header. Mirrors extractTextsFromParts in message-parser.ts.
+//
+// Server-side counterpart in workspace-server/internal/channels/
+// manager.go has the same single-part bug; fix that too if/when a
+// channel-delivered reply (Slack, Lark, etc.) gets truncated.
+export function extractReplyText(resp: A2AResponse): string {
+  const collect = (parts: A2APart[] | undefined): string => {
+    if (!parts) return "";
+    return parts
+      .filter((p) => p.kind === "text")
+      .map((p) => p.text ?? "")
+      .filter(Boolean)
+      .join("\n");
+  };
+  const result = resp?.result;
+  const collected: string[] = [];
+  const fromParts = collect(result?.parts);
+  if (fromParts) collected.push(fromParts);
+  // Walk artifacts even if parts had text — some producers (Hermes
+  // tool calls) emit a summary in parts AND details in artifacts.
+  // Returning early on parts dropped the artifact body silently.
+  if (result?.artifacts) {
+    for (const a of result.artifacts) {
+      const t = collect(a.parts);
+      if (t) collected.push(t);
+    }
+  }
+  return collected.join("\n");
+}
+
+// Agent-returned files live on the same response shape as text —
+// delegated to extractFilesFromTask in message-parser.ts, which also
+// walks status.message.parts (that ChatTab's legacy text extractor
+// doesn't). Single source of truth for file-part parsing across
+// live chat, activity log replay, and any future consumers.
+
+/** Initial chat history page size. The newest N messages are rendered
+ *  on first paint; older history is fetched on demand via loadOlder()
+ *  when the user scrolls the top sentinel into view. */
+const INITIAL_HISTORY_LIMIT = 10;
+/** Subsequent older-history batch size. Larger than INITIAL so a long
+ *  scroll-back doesn't fan out into many round-trips. */
+const OLDER_HISTORY_BATCH = 20;
+
+/**
+ * Load chat history from the platform's typed /chat-history endpoint.
+ *
+ * Server-side rendering of activity_logs rows into ChatMessage shape
+ * lives in workspace-server/internal/messagestore/postgres_store.go
+ * (RFC #2945 PR-C/D). The server already applies the canvas-source
+ * filter, the internal-self-message predicate, the role decision
+ * (status=error vs agent-error prefix → system), and the v0/v1
+ * file-shape extraction. Canvas just renders what it receives.
+ *
+ * Wire shape (mirrors ChatMessage exactly, no per-row mapping needed):
+ *
+ *   GET /workspaces/:id/chat-history?limit=N&before_ts=T
+ *   200 → {"messages": ChatMessage[], "reached_end": boolean}
+ *
+ * Pagination:
+ *  - Pass `limit` to bound the page size (newest-first from server).
+ *  - Pass `beforeTs` (RFC3339) to fetch rows STRICTLY OLDER than that
+ *    timestamp. Combined with limit, this yields the next-older page
+ *    when scrolling backward through history.
+ *
+ * `reachedEnd` is propagated from the server. The server computes it
+ * by comparing rowCount vs limit so a partial last page is correctly
+ * detected even when the row→bubble fan-out is non-1:1 (each row
+ * produces 1-2 bubbles).
+ */
+async function loadMessagesFromDB(
+  workspaceId: string,
+  limit: number,
+  beforeTs?: string,
+): Promise<{ messages: ChatMessage[]; error: string | null; reachedEnd: boolean }> {
+  try {
+    const params = new URLSearchParams({ limit: String(limit) });
+    if (beforeTs) params.set("before_ts", beforeTs);
+    const resp = await api.get<{ messages: ChatMessage[]; reached_end: boolean }>(
+      `/workspaces/${workspaceId}/chat-history?${params.toString()}`,
+    );
+
+    // Server emits oldest-first within the page (RFC #2945 PR-C-2
+    // post-fix: server reverses row-aware before returning so the
+    // wire is display-ready). Canvas appends/prepends without
+    // reordering — this avoids the pair-flip bug a naive flat
+    // reverse causes when each row produces a (user, agent) pair
+    // with the same timestamp.
+    return {
+      messages: resp.messages ?? [],
+      error: null,
+      reachedEnd: resp.reached_end,
+    };
+  } catch (err) {
+    return {
+      messages: [],
+      error: err instanceof Error ? err.message : "Failed to load chat history",
+      reachedEnd: true,
+    };
+  }
+}
+
 /**
  * ChatTab container — renders sub-tab bar + My Chat or Agent Comms panel.
  */
@@ -108,68 +247,268 @@ export function ChatTab({ workspaceId, data }: Props) {
  * MyChatPanel — user↔agent conversation (extracted from original ChatTab).
  */
 function MyChatPanel({ workspaceId, data }: Props) {
+  const [messages, setMessages] = useState<ChatMessage[]>([]);
   const [input, setInput] = useState("");
-  const [pendingFiles, setPendingFiles] = useState<File[]>([]);
-  const [activityLog, setActivityLog] = useState<string[]>([]);
+  // `sending` is strictly the "this tab kicked off a send and hasn't
+  // seen the reply yet" signal. Previously this was initialized from
+  // data.currentTask to pick up in-flight agent work on mount, but
+  // that conflated agent-busy (workspace heartbeat) with user-
+  // in-flight (local send): when the WS dropped a TASK_COMPLETE event,
+  // currentTask lingered, the component re-mounted with sending=true,
+  // and the Send button stayed disabled forever even though nothing
+  // local was in flight. For the "agent is busy, show spinner" UX,
+  // use data.currentTask directly in the render path.
+  const [sending, setSending] = useState(false);
   const [thinkingElapsed, setThinkingElapsed] = useState(0);
+  const [activityLog, setActivityLog] = useState<string[]>([]);
+  const [loading, setLoading] = useState(true);
+  const [loadError, setLoadError] = useState<string | null>(null);
+  const currentTaskRef = useRef(data.currentTask);
+  const sendingFromAPIRef = useRef(false);
   const [agentReachable, setAgentReachable] = useState(false);
   const [error, setError] = useState<string | null>(null);
   const [confirmRestart, setConfirmRestart] = useState(false);
-  const [dragOver, setDragOver] = useState(false);
-
+  const bottomRef = useRef<HTMLDivElement>(null);
+  // First-mount scroll-to-bottom needs `behavior: "instant"` — long
+  // conversations smooth-animate for ~300ms which any concurrent
+  // re-render can interrupt, leaving the user stuck mid-conversation
+  // when the chat tab opens. Subsequent appends (new agent messages)
+  // keep `smooth` for the visual "landing" feel. Flipped the first
+  // time messages.length goes positive, so a workspace switch (which
+  // remounts ChatTab) gets a fresh instant jump too.
+  const hasInitialScrollRef = useRef(false);
+  // Lazy-load older history on scroll-up.
+  // - containerRef = the scrollable messages viewport
+  // - topRef       = sentinel above the messages list; IO observes it
+  //                  and triggers loadOlder() when it enters view
+  // - hasMore      = false once a fetch returns < limit rows; stops IO
+  // - loadingOlder = drives the "Loading older messages…" UI label
+  // - inflightRef  = synchronous guard against double-entry of loadOlder
+  //                  when the IO callback fires twice in the same
+  //                  microtask (state-based guard would be stale until
+  //                  the next React commit)
+  // - scrollAnchorRef = saves distance-from-bottom before a prepend
+  //                  so the useLayoutEffect below can restore the
+  //                  user's exact viewport position. Without this,
+  //                  prepending older messages would jump the scroll
+  //                  position by the height of the new content.
+  // - oldestMessageRef / hasMoreRef = let the loadOlder closure read
+  //                  the latest values without taking them as deps —
+  //                  every live agent push mutates `messages`, and
+  //                  having loadOlder depend on `messages` would tear
+  //                  down + re-arm the IntersectionObserver on every
+  //                  push. Refs decouple the observer lifecycle from
+  //                  message-list updates.
   const containerRef = useRef<HTMLDivElement>(null);
   const topRef = useRef<HTMLDivElement>(null);
-  const bottomRef = useRef<HTMLDivElement>(null);
-  const hasInitialScrollRef = useRef(false);
+  const [hasMore, setHasMore] = useState(true);
+  const [loadingOlder, setLoadingOlder] = useState(false);
+  const inflightRef = useRef(false);
+  // The scroll anchor includes the first-message id as it was BEFORE
+  // the prepend — see useLayoutEffect below for why. Without this tag,
+  // a live agent push that appends WHILE loadOlder is in flight would
+  // run useLayoutEffect against the append (anchor still set), the
+  // "restore" math would scroll the user to a stale offset, AND the
+  // append's normal scroll-to-bottom would be swallowed.
+  const scrollAnchorRef = useRef<
+    { savedDistanceFromBottom: number; expectFirstIdNotEqual: string | null } | null
+  >(null);
+  const oldestMessageRef = useRef<ChatMessage | null>(null);
+  const hasMoreRef = useRef(true);
+  // Monotonic token bumped on workspace switch + on every loadOlder
+  // entry. Each fetch's .then() captures its own token; if the token
+  // has moved, the resolved messages belong to a stale workspace or a
+  // superseded fetch and we silently drop them. Without this guard, a
+  // workspace switch mid-fetch would have the in-flight promise
+  // resolve into the new workspace's setMessages — the user sees
+  // someone else's history briefly.
+  const fetchTokenRef = useRef(0);
+  // Files the user has picked but not yet sent. Cleared on send
+  // (upload success) or by the × on each pill.
+  const [pendingFiles, setPendingFiles] = useState<File[]>([]);
+  const [uploading, setUploading] = useState(false);
   const fileInputRef = useRef<HTMLInputElement>(null);
-  const dragDepthRef = useRef(0);
-  const pasteCounterRef = useRef(0);
+  // Guard against a double-click during the upload phase: React
+  // state updates from the click that started the upload haven't
+  // flushed yet, so the disabled-button logic sees `uploading=false`
+  // from the closure and lets a second `sendMessage` enter. A ref
+  // observes the latest value synchronously.
+  const sendInFlightRef = useRef(false);
+  // Monotonic token bumped on every sendMessage entry. Each .then()/
+  // .catch() captures its own token in closure and bails if a newer
+  // send has superseded it — prevents a late HTTP response for an
+  // earlier message from clobbering the flags / appending text that
+  // belong to a newer in-flight send. Race scenario the token closes:
+  // (1) send msg #1 (2) WS push for msg #1 arrives, releases guards
+  // (3) user sends msg #2 (4) HTTP for msg #1 finally lands — without
+  // the token check, .then() sees sendingFromAPIRef=true (set by
+  // msg #2's send), enters the main body, and processes msg #1's body
+  // as if it were msg #2's reply.
+  const sendTokenRef = useRef(0);
 
-  const history = useChatHistory(workspaceId, containerRef);
-  const chatSend = useChatSend(workspaceId, {
-    getHistoryMessages: () => history.messages,
-    onUserMessage: (msg) => history.setMessages((prev) => [...prev, msg]),
-    onAgentMessage: (msg) => history.setMessages((prev) => appendMessageDeduped(prev, msg)),
-  });
-  const { sending, uploading, sendMessage, error: sendError, clearError: clearSendError, releaseSendGuards, sendingFromAPIRef } = chatSend;
+  // Release every in-flight send guard at once. Used by every site
+  // that ends a send: pendingAgentMsgs WS push, ACTIVITY_LOGGED
+  // a2a_receive ok/error WS event, HTTP .then() success, and HTTP
+  // .catch() success. Keep these in lockstep — a future contributor
+  // adding a new "I saw the reply" path that only clears `sending` +
+  // `sendingFromAPIRef` (the natural pair) silently re-introduces
+  // the post-WS Send-button freeze, because the disabled-button
+  // logic can't see `sendInFlightRef` and so the visible state diverges
+  // from the synchronous re-entry guard at line 464.
+  const releaseSendGuards = useCallback(() => {
+    setSending(false);
+    sendingFromAPIRef.current = false;
+    sendInFlightRef.current = false;
+  }, []);
 
-  const displayError = error || sendError;
+  // Initial-load fetch — used by the mount effect and the "Retry"
+  // button below. Single source of truth so the two paths can't drift
+  // (e.g. INITIAL_HISTORY_LIMIT bumped in the effect but not the
+  // retry, leading to inconsistent first-paint sizes).
+  const loadInitial = useCallback(() => {
+    setLoading(true);
+    setLoadError(null);
+    setHasMore(true);
+    // Bump the token; any in-flight fetch from the previous workspace
+    // (or a previous retry) will see token != myToken in its .then()
+    // and silently bail — the late response can't clobber the new
+    // workspace's state.
+    fetchTokenRef.current += 1;
+    const myToken = fetchTokenRef.current;
+    loadMessagesFromDB(workspaceId, INITIAL_HISTORY_LIMIT).then(
+      ({ messages: msgs, error: fetchErr, reachedEnd }) => {
+        if (fetchTokenRef.current !== myToken) return;
+        setMessages(msgs);
+        setLoadError(fetchErr);
+        setHasMore(!reachedEnd);
+        setLoading(false);
+      },
+    );
+  }, [workspaceId]);
 
-  useChatSocket(workspaceId, {
-    onAgentMessage: (msg) => {
-      history.setMessages((prev) => appendMessageDeduped(prev, msg));
-      if (sendingFromAPIRef.current) {
-        releaseSendGuards();
+  // Load chat history on mount / workspace switch.
+  // Initial load is bounded to INITIAL_HISTORY_LIMIT (newest 10) — the
+  // rest streams in as the user scrolls up via loadOlder() below. Pre-
+  // 2026-05-05 this fetched the newest 50 in one shot; on a long-running
+  // workspace that meant 50× message-bubble paint + DOM cost on every
+  // tab-open even when the user only wanted to read the last few.
+  useEffect(() => {
+    loadInitial();
+  }, [loadInitial]);
+
+  // Mirror the latest oldest-message + hasMore into refs so loadOlder
+  // can read them without taking `messages` as a dep. Every live push
+  // through agentMessages would otherwise recreate loadOlder and tear
+  // down the IO observer.
+  useEffect(() => {
+    oldestMessageRef.current = messages[0] ?? null;
+  }, [messages]);
+  useEffect(() => {
+    hasMoreRef.current = hasMore;
+  }, [hasMore]);
+
+  // Fetch the next-older batch and prepend. Stable identity (deps =
+  // [workspaceId]) so the IntersectionObserver effect below doesn't
+  // re-arm on every messages update.
+  const loadOlder = useCallback(async () => {
+    // inflightRef is the load-bearing guard — synchronous, set BEFORE
+    // any await, so two IO callbacks dispatched in the same microtask
+    // can't both pass. The state checks are defensive secondary
+    // gates for the slow-scroll case.
+    if (inflightRef.current || !hasMoreRef.current) return;
+    const oldest = oldestMessageRef.current;
+    if (!oldest) return;
+    const container = containerRef.current;
+    if (!container) return;
+    inflightRef.current = true;
+    // Capture the user's distance-from-bottom BEFORE we prepend so the
+    // useLayoutEffect can restore it after the new DOM lands. The
+    // expectFirstIdNotEqual tag is what the layout effect checks
+    // against `messages[0].id` to disambiguate prepend (id changed) vs
+    // append (id unchanged → live message landed mid-fetch). Without
+    // it, an agent push during loadOlder runs the "restore" against a
+    // stale anchor — user gets yanked + the append's bottom-pin is
+    // swallowed.
+    scrollAnchorRef.current = {
+      savedDistanceFromBottom: container.scrollHeight - container.scrollTop,
+      expectFirstIdNotEqual: oldest.id,
+    };
+    fetchTokenRef.current += 1;
+    const myToken = fetchTokenRef.current;
+    setLoadingOlder(true);
+    try {
+      const { messages: older, reachedEnd } = await loadMessagesFromDB(
+        workspaceId,
+        OLDER_HISTORY_BATCH,
+        oldest.timestamp,
+      );
+      // Workspace switched (or another loadOlder bumped the token)
+      // mid-fetch — drop these results, they belong to a stale tab.
+      if (fetchTokenRef.current !== myToken) {
+        scrollAnchorRef.current = null;
+        return;
       }
-    },
-    onActivityLog: (entry) => {
-      if (!sending) return;
-      setActivityLog((prev) => appendActivityLine(prev, entry));
-    },
-    onSendComplete: () => {
-      if (sendingFromAPIRef.current) {
-        releaseSendGuards();
+      if (older.length > 0) {
+        setMessages((prev) => [...older, ...prev]);
+      } else {
+        // Nothing came back — clear the anchor so the next paint doesn't
+        // try to "restore" against a no-op prepend.
+        scrollAnchorRef.current = null;
       }
-    },
-    onSendError: (err) => {
-      if (sendingFromAPIRef.current) {
-        releaseSendGuards();
-        setError(err);
-      }
-    },
-  });
+      setHasMore(!reachedEnd);
+    } finally {
+      setLoadingOlder(false);
+      inflightRef.current = false;
+    }
+  }, [workspaceId]);
+
+  // IntersectionObserver on the top sentinel. Fires loadOlder() the
+  // moment the user scrolls within 200px of the top. AbortController
+  // unwires cleanly on workspace switch / unmount; root is the
+  // scrollable container so we observe only what's visible inside it.
+  //
+  // Dependencies:
+  //  - loadOlder    — stable per workspaceId (refs decouple it from
+  //                   message updates), so this dep is here for the
+  //                   workspace-switch case only
+  //  - hasMore      — re-run when older history runs out so we
+  //                   disconnect cleanly
+  //  - hasMessages  — load-bearing: the sentinel JSX is gated on
+  //                   `messages.length > 0`, so topRef.current is null
+  //                   on the empty-messages render. We re-arm exactly
+  //                   once when messages first land. NOT depending on
+  //                   `messages.length` (or `messages`) directly so
+  //                   each subsequent message append doesn't tear down
+  //                   + re-arm the observer.
+  const hasMessages = messages.length > 0;
+  useEffect(() => {
+    const top = topRef.current;
+    const container = containerRef.current;
+    if (!top || !container) return;
+    if (!hasMore) return; // stop observing when no older history exists
+    const ac = new AbortController();
+    const io = new IntersectionObserver(
+      (entries) => {
+        if (ac.signal.aborted) return;
+        if (entries[0]?.isIntersecting) loadOlder();
+      },
+      { root: container, rootMargin: "200px 0px 0px 0px", threshold: 0 },
+    );
+    io.observe(top);
+    ac.signal.addEventListener("abort", () => io.disconnect());
+    return () => ac.abort();
+  }, [loadOlder, hasMore, hasMessages]);
 
   // Agent reachability
   useEffect(() => {
     const reachable = data.status === "online" || data.status === "degraded";
     setAgentReachable(reachable);
-    if (reachable) {
-      setError(null);
-      clearSendError();
-    } else {
-      setError(`Agent is ${data.status}`);
-    }
-  }, [data.status, clearSendError]);
+    setError(reachable ? null : `Agent is ${data.status}`);
+  }, [data.status]);
+
+  useEffect(() => {
+    currentTaskRef.current = data.currentTask;
+  }, [data.currentTask]);
 
   // Scroll behavior across messages updates:
   //  - Prepend (loadOlder landed)  → restore the user's saved
@@ -179,24 +518,71 @@ function MyChatPanel({ workspaceId, data }: Props) {
   // paint — otherwise the user sees the page jump for one frame.
   useLayoutEffect(() => {
     const container = containerRef.current;
-    const anchor = history.scrollAnchorRef.current;
+    const anchor = scrollAnchorRef.current;
+    // Only honor the anchor when this messages-update is the prepend
+    // we expected. messages[0].id is the test:
+    //   - prepend  → messages[0] is one of the older rows → id !== expectFirstIdNotEqual
+    //   - append   → messages[0] unchanged → id === expectFirstIdNotEqual → fall through
+    // Without this check, an agent push that lands mid-loadOlder would
+    // run the restore against the append's update, yank the user's
+    // scroll, AND swallow the append's bottom-pin.
     if (
       anchor &&
       container &&
-      history.messages.length > 0 &&
-      history.messages[0].id !== anchor.expectFirstIdNotEqual
+      messages.length > 0 &&
+      messages[0].id !== anchor.expectFirstIdNotEqual
     ) {
       container.scrollTop = container.scrollHeight - anchor.savedDistanceFromBottom;
-      history.scrollAnchorRef.current = null;
+      scrollAnchorRef.current = null;
       return;
     }
-    if (!hasInitialScrollRef.current && history.messages.length > 0) {
+    // Instant on first arrival of messages — smooth-scroll on a long
+    // conversation gets interrupted by concurrent renders and leaves
+    // the user stuck in the middle. After the first jump, subsequent
+    // appends animate as before.
+    if (!hasInitialScrollRef.current && messages.length > 0) {
       hasInitialScrollRef.current = true;
       bottomRef.current?.scrollIntoView({ behavior: "instant" as ScrollBehavior });
       return;
     }
     bottomRef.current?.scrollIntoView({ behavior: "smooth" });
-  }, [history.messages, history.scrollAnchorRef]);
+  }, [messages]);
+
+  // Consume agent push messages (send_message_to_user) from global store.
+  // Runtimes like Claude Code SDK deliver their reply via a WS push rather
+  // than the /a2a HTTP response — when that happens, the push is the
+  // authoritative "reply arrived" signal for the UI, so clear `sending`
+  // here too. The HTTP .then() coordinates through sendingFromAPIRef so
+  // whichever path clears first wins.
+  const pendingAgentMsgs = useCanvasStore((s) => s.agentMessages[workspaceId]);
+  useEffect(() => {
+    if (!pendingAgentMsgs || pendingAgentMsgs.length === 0) return;
+    const consume = useCanvasStore.getState().consumeAgentMessages;
+    const msgs = consume(workspaceId);
+    for (const m of msgs) {
+      // Dedupe in case the agent proactively pushed the same text the
+      // HTTP /a2a response already delivered (observed with the Hermes
+      // runtime, which emits both a reply body and a send_message_to_user
+      // push for the same content). Attachments ride along with the
+      // message so files returned by the A2A_RESPONSE WS path render
+      // their download chips.
+      setMessages((prev) => appendMessageDeduped(prev, createMessage("agent", m.content, m.attachments)));
+    }
+    if (sendingFromAPIRef.current && msgs.length > 0) {
+      // Reply arrived via WS push (e.g. claude-code SDK). Release all
+      // three guards together — without sendInFlightRef the next
+      // sendMessage() silently no-ops at the synchronous re-entry
+      // check.
+      releaseSendGuards();
+    }
+  }, [pendingAgentMsgs, workspaceId]);
+
+  // Resolve workspace ID → name for activity display
+  const resolveWorkspaceName = useCallback((id: string) => {
+    const nodes = useCanvasStore.getState().nodes;
+    const node = nodes.find((n) => n.id === id);
+    return (node?.data as WorkspaceNodeData)?.name || id.slice(0, 8);
+  }, []);
 
   // Elapsed timer while sending
   useEffect(() => {
@@ -223,43 +609,211 @@ function MyChatPanel({ workspaceId, data }: Props) {
     setActivityLog([`Processing with ${runtimeDisplayName(data.runtime)}...`]);
   }, [sending, data.runtime]);
 
-  // IntersectionObserver on the top sentinel. Fires loadOlder() the
-  // moment the user scrolls within 200px of the top. AbortController
-  // unwires cleanly on workspace switch / unmount; root is the
-  // scrollable container so we observe only what's visible inside it.
-  const hasMessages = history.messages.length > 0;
-  useEffect(() => {
-    const top = topRef.current;
-    const container = containerRef.current;
-    if (!top || !container) return;
-    if (!history.hasMore) return;
-    const ac = new AbortController();
-    const io = new IntersectionObserver(
-      (entries) => {
-        if (ac.signal.aborted) return;
-        if (entries[0]?.isIntersecting) history.loadOlder();
-      },
-      { root: container, rootMargin: "200px 0px 0px 0px", threshold: 0 },
-    );
-    io.observe(top);
-    ac.signal.addEventListener("abort", () => io.disconnect());
-    return () => ac.abort();
-  }, [history.loadOlder, history.hasMore, hasMessages]);
+  // Subscribe to global WS via the singleton ReconnectingSocket (no
+  // per-component WebSocket — the previous pattern dropped events
+  // silently on any reconnect because each panel's raw socket had no
+  // onclose handler).
+  useSocketEvent((msg) => {
+    if (!sending) return;
+    try {
+        if (msg.event === "ACTIVITY_LOGGED") {
+          // Filter to events for THIS workspace. The platform's
+          // BroadcastOnly fires to every connected client, and
+          // without this guard a sibling workspace's a2a_send would
+          // surface as "→ Delegating to X..." inside the wrong
+          // chat panel. (workspace_id on the WS envelope is the
+          // workspace whose activity_log row we just wrote.)
+          if (msg.workspace_id !== workspaceId) return;
 
-  const handleSend = async () => {
+          const p = msg.payload || {};
+          const type = p.activity_type as string;
+          const method = (p.method as string) || "";
+          const status = (p.status as string) || "";
+          const targetId = (p.target_id as string) || "";
+          const durationMs = p.duration_ms as number | undefined;
+          const summary = (p.summary as string) || "";
+
+          let line = "";
+          if (type === "a2a_receive" && method === "message/send") {
+            const targetName = resolveWorkspaceName(targetId || msg.workspace_id);
+            if (status === "ok" && durationMs) {
+              const sec = Math.round(durationMs / 1000);
+              line = `← ${targetName} responded (${sec}s)`;
+              // The platform logs a successful a2a_receive once the workspace
+              // has fully produced its reply. That's the authoritative "done"
+              // signal for the spinner — clear it even if the reply hasn't
+              // surfaced through the store yet (it may be delivered shortly
+              // via pendingAgentMsgs or the HTTP .then()).
+              const own = (targetId || msg.workspace_id) === workspaceId;
+              if (own && sendingFromAPIRef.current) {
+                releaseSendGuards();
+              }
+            } else if (status === "error") {
+              line = `⚠ ${targetName} error`;
+              const own = (targetId || msg.workspace_id) === workspaceId;
+              if (own && sendingFromAPIRef.current) {
+                releaseSendGuards();
+                setError("Agent error (Exception) — see workspace logs for details.");
+              }
+            }
+          } else if (type === "a2a_send") {
+            const targetName = resolveWorkspaceName(targetId);
+            line = `→ Delegating to ${targetName}...`;
+          } else if (type === "task_update") {
+            if (summary) line = `⟳ ${summary}`;
+          } else if (type === "agent_log") {
+            // Per-tool-use telemetry from claude_sdk_executor's
+            // _report_tool_use. The summary already carries an icon
+            // + human-readable args (📄 Read /path, ⚡ Bash: …)
+            // so we render it verbatim. No icon prefix here — the
+            // emoji at the start of summary is the visual marker.
+            if (summary) line = summary;
+          }
+
+          if (line) {
+            setActivityLog((prev) => appendActivityLine(prev, line));
+          }
+        } else if (msg.event === "TASK_UPDATED" && msg.workspace_id === workspaceId) {
+          const task = (msg.payload?.current_task as string) || "";
+          if (task) {
+            setActivityLog((prev) => appendActivityLine(prev, `⟳ ${task}`));
+          }
+        }
+        // A2A_RESPONSE is already consumed by the store and its text is
+        // appended to messages via the pendingAgentMsgs effect above; we
+        // don't need to duplicate it here.
+    } catch { /* ignore */ }
+  });
+
+  const sendMessage = async () => {
     const text = input.trim();
-    const files = pendingFiles;
-    if ((!text && files.length === 0) || !agentReachable || sending || uploading) return;
+    const filesToSend = pendingFiles;
+    // Allow sending if EITHER text OR attachments are present — a user
+    // can drop a file with no text and the agent still receives it.
+    if ((!text && filesToSend.length === 0) || !agentReachable || sending || uploading) return;
+    // Synchronous re-entry guard — see sendInFlightRef comment.
+    if (sendInFlightRef.current) return;
+    sendInFlightRef.current = true;
+
+    // Upload attachments first so we can include URIs in the A2A
+    // message parts. Sequential-before-send: a message with references
+    // to files not yet staged would fail agent-side; staging happens
+    // synchronously via /chat/uploads before message/send dispatch.
+    let uploaded: ChatAttachment[] = [];
+    if (filesToSend.length > 0) {
+      setUploading(true);
+      try {
+        uploaded = await uploadChatFiles(workspaceId, filesToSend);
+      } catch (e) {
+        setUploading(false);
+        sendInFlightRef.current = false;
+        setError(e instanceof Error ? `Upload failed: ${e.message}` : "Upload failed");
+        return;
+      }
+      setUploading(false);
+    }
+
     setInput("");
     setPendingFiles([]);
-    clearSendError();
+    setMessages((prev) => [...prev, createMessage("user", text, uploaded)]);
+    setSending(true);
+    sendingFromAPIRef.current = true;
     setError(null);
-    await sendMessage(text, files);
+    // Capture this send's token so the .then()/.catch() callbacks can
+    // detect a newer send that may have superseded them. See the
+    // sendTokenRef declaration for the race scenario this closes.
+    const myToken = ++sendTokenRef.current;
+
+    // Build conversation history from prior messages (last 20)
+    const history = messages
+      .filter((m) => m.role === "user" || m.role === "agent")
+      .slice(-20)
+      .map((m) => ({
+        role: m.role === "user" ? "user" : "agent",
+        parts: [{ kind: "text", text: m.content }],
+      }));
+
+    // A2A parts: text part (if any) + file parts (per attachment). The
+    // agent sees both in a single turn, matching the A2A spec shape.
+    // Wire shape is v0 — see A2APart definition above.
+    const parts: A2APart[] = [];
+    if (text) parts.push({ kind: "text", text });
+    for (const att of uploaded) {
+      parts.push({
+        kind: "file",
+        file: {
+          name: att.name,
+          mimeType: att.mimeType,
+          uri: att.uri,
+          size: att.size,
+        },
+      });
+    }
+
+    // A2A calls can legitimately take minutes — LLM latency +
+    // multi-turn tool use is common on slower providers (Hermes+minimax,
+    // Claude Code invoking bash/file tools, etc.). The 15s default
+    // would silently abort the fetch here, leaving the server to
+    // complete the reply and the user staring at
+    // "agent may be unreachable". Match the upload timeout (60s × 2)
+    // for the happy-path ceiling; anything longer is genuinely stuck.
+    api.post<A2AResponse>(`/workspaces/${workspaceId}/a2a`, {
+      method: "message/send",
+      params: {
+        message: {
+          role: "user",
+          messageId: crypto.randomUUID(),
+          parts,
+        },
+        metadata: { history },
+      },
+    }, { timeoutMs: 120_000 })
+      .then((resp) => {
+        // Bail without touching any flags if a newer sendMessage has
+        // already run — its myToken bumped sendTokenRef, so this is
+        // a stale callback for an earlier message. The newer send
+        // owns the in-flight guards now.
+        if (sendTokenRef.current !== myToken) return;
+        // Skip if the WS A2A_RESPONSE event already handled this response.
+        // Both paths (WS + HTTP) check sendingFromAPIRef — whichever clears
+        // it first wins, the other becomes a no-op (no duplicate messages).
+        if (!sendingFromAPIRef.current) {
+          sendInFlightRef.current = false;
+          return;
+        }
+        const replyText = extractReplyText(resp);
+        const replyFiles = extractFilesFromTask((resp?.result ?? {}) as Record<string, unknown>);
+        if (replyText || replyFiles.length > 0) {
+          setMessages((prev) =>
+            appendMessageDeduped(prev, createMessage("agent", replyText, replyFiles)),
+          );
+        }
+        releaseSendGuards();
+      })
+      .catch(() => {
+        // Stale-callback guard — same rationale as .then().
+        if (sendTokenRef.current !== myToken) return;
+        // Same dedup guard as .then(): if a WS path (pendingAgentMsgs
+        // or ACTIVITY_LOGGED a2a_receive ok) already delivered the
+        // reply, sendingFromAPIRef is already false and there's
+        // nothing to roll back. Surfacing "Failed to send" here would
+        // contradict the agent reply the user is currently reading —
+        // exactly the false-positive observed when the HTTP request
+        // hung up (proxy idle / 502) after WS already won.
+        if (!sendingFromAPIRef.current) {
+          sendInFlightRef.current = false;
+          return;
+        }
+        releaseSendGuards();
+        setError("Failed to send message — agent may be unreachable");
+      });
   };
 
   const onFilesPicked = (fileList: FileList | null) => {
     if (!fileList) return;
     const picked = Array.from(fileList);
+    // Deduplicate against current pending set by name+size — user
+    // picking the same file twice shouldn't append it.
     setPendingFiles((prev) => {
       const keyed = new Set(prev.map((f) => `${f.name}:${f.size}`));
       return [...prev, ...picked.filter((f) => !keyed.has(`${f.name}:${f.size}`))];
@@ -270,7 +824,35 @@ function MyChatPanel({ workspaceId, data }: Props) {
   const removePendingFile = (index: number) =>
     setPendingFiles((prev) => prev.filter((_, i) => i !== index));
 
+  // Monotonic counter so two paste events within the same wall-clock
+  // second still produce distinct filenames. Without this, on
+  // Firefox (where pasted images have an empty `file.name`), two
+  // pastes ~100ms apart could yield identical synthetic names AND
+  // identical sizes, collapsing into one attachment via the
+  // `name:size` dedup in onFilesPicked.
+  const pasteCounterRef = useRef(0);
+
+  /** Paste-from-clipboard image attachment.
+   *
+   *  Browser clipboard image items arrive as `File`s whose `name` is
+   *  often a generic "image.png" (Chrome) or empty (Firefox/Safari),
+   *  so two consecutive screenshot pastes collide on the name+size
+   *  dedup the file-picker uses. Re-tag each pasted image with a
+   *  per-paste unique name so dedup keeps them apart and the upload
+   *  pipeline (which expects a non-empty filename) is happy.
+   *
+   *  Falls through to onFilesPicked via direct File[] (NOT through
+   *  the DataTransfer constructor — that throws on Safari < 14.1
+   *  and old Edge, silently aborting the paste).
+   *
+   *  Only intercepts the paste when the clipboard has at least one
+   *  image; text-only pastes fall through to the textarea's default
+   *  behaviour. */
   const mimeToExt = (mime: string): string => {
+    // Avoid raw `mime.split("/")[1]` — that yields `"svg+xml"`,
+    // `"jpeg"`, `"webp"` etc. which produce ugly filenames and may
+    // trip server-side extension allowlists. Map known types
+    // explicitly; unknown falls back to a safe default.
     if (mime === "image/svg+xml") return "svg";
     if (mime === "image/jpeg") return "jpg";
     if (mime === "image/png") return "png";
@@ -291,16 +873,26 @@ function MyChatPanel({ workspaceId, data }: Props) {
       const file = item.getAsFile();
       if (!file) continue;
       const ext = mimeToExt(file.type);
-      const stamp = new Date().toISOString().replace(/[:.]/g, "-").slice(0, 19);
+      const stamp = new Date()
+        .toISOString()
+        .replace(/[:.]/g, "-")
+        .slice(0, 19);
       const seq = pasteCounterRef.current++;
       const fname = `pasted-${stamp}-${seq}-${i}.${ext}`;
       imageFiles.push(new File([file], fname, { type: file.type }));
     }
     if (imageFiles.length === 0) return;
     e.preventDefault();
+    // Reuse the picker path so file-size guards, dedup, and pending-
+    // list state all run through the same code. Build a synthetic
+    // FileList-like object to avoid the DataTransfer constructor —
+    // that's missing on Safari < 14.1 / old Edge and would silently
+    // throw, leaving the paste a no-op.
     addPastedFiles(imageFiles);
   };
 
+  // Variant of onFilesPicked that accepts a File[] directly, sidestepping
+  // the DataTransfer-FileList round-trip. Same dedup + state shape.
   const addPastedFiles = (files: File[]) => {
     setPendingFiles((prev) => {
       const keyed = new Set(prev.map((f) => `${f.name}:${f.size}`));
@@ -308,6 +900,11 @@ function MyChatPanel({ workspaceId, data }: Props) {
     });
   };
 
+  // Drag-and-drop staging. dragDepthRef counts enter vs leave events so
+  // the overlay doesn't flicker when the cursor crosses nested children
+  // (textarea, buttons) — dragenter/dragleave fire for every boundary.
+  const [dragOver, setDragOver] = useState(false);
+  const dragDepthRef = useRef(0);
   const dropEnabled = agentReachable && !sending && !uploading;
   const isFileDrag = (e: React.DragEvent) =>
     Array.from(e.dataTransfer.types || []).includes("Files");
@@ -337,6 +934,9 @@ function MyChatPanel({ workspaceId, data }: Props) {
   };
 
   const downloadAttachment = (att: ChatAttachment) => {
+    // Errors here are rare but user-visible (401 on a revoked token,
+    // 404 if the agent deleted the file). Surface via the inline
+    // error banner — the message list itself stays untouched.
     downloadChatFile(workspaceId, att).catch((e) => {
       setError(e instanceof Error ? `Download failed: ${e.message}` : "Download failed");
     });
@@ -364,26 +964,26 @@ function MyChatPanel({ workspaceId, data }: Props) {
       )}
       {/* Messages */}
       <div ref={containerRef} className="flex-1 overflow-y-auto p-3 space-y-3">
-        {history.loading && (
+        {loading && (
           <div className="text-xs text-ink-mid text-center py-4">Loading chat history...</div>
         )}
-        {!history.loading && history.loadError !== null && history.messages.length === 0 && (
+        {!loading && loadError !== null && messages.length === 0 && (
           <div
             role="alert"
             className="mx-2 mt-2 rounded-lg border border-red-800/50 bg-red-950/30 px-3 py-2.5"
           >
             <p className="text-[11px] text-bad mb-1.5">
-              Failed to load chat history: {history.loadError}
+              Failed to load chat history: {loadError}
             </p>
             <button
-              onClick={history.loadInitial}
+              onClick={loadInitial}
               className="text-[10px] px-2 py-0.5 rounded bg-red-800 text-red-200 hover:bg-red-700 transition-colors"
             >
               Retry
             </button>
           </div>
         )}
-        {!history.loading && history.loadError === null && history.messages.length === 0 && (
+        {!loading && loadError === null && messages.length === 0 && (
           <div className="text-xs text-ink-mid text-center py-8">
             No messages yet. Send a message to start chatting with this agent.
           </div>
@@ -401,12 +1001,12 @@ function MyChatPanel({ workspaceId, data }: Props) {
             instead of showing a "no more messages" footer — the user's
             scroll resting against the top of the conversation IS the
             signal. */}
-        {history.hasMore && history.messages.length > 0 && (
+        {hasMore && messages.length > 0 && (
           <div ref={topRef} className="text-xs text-ink-mid text-center py-1">
-            {history.loadingOlder ? "Loading older messages…" : " "}
+            {loadingOlder ? "Loading older messages…" : " "}
           </div>
         )}
-        {history.messages.map((msg) => (
+        {messages.map((msg) => (
           <div key={msg.id} className={`flex ${msg.role === "user" ? "justify-end" : "justify-start"}`}>
             <div
               className={`max-w-[85%] rounded-lg px-3 py-2 text-xs ${
@@ -566,10 +1166,10 @@ function MyChatPanel({ workspaceId, data }: Props) {
       </div>
 
       {/* Error banner */}
-      {displayError && (
+      {error && (
         <div className="px-3 py-2 bg-red-900/20 border-t border-red-800/30">
           <div className="flex items-center justify-between">
-            <span className="text-[10px] text-red-300">{displayError}</span>
+            <span className="text-[10px] text-red-300">{error}</span>
             {!isOnline && (
               <button
                 onClick={() => setConfirmRestart(true)}
@@ -637,7 +1237,7 @@ function MyChatPanel({ workspaceId, data }: Props) {
                 e.keyCode !== 229
               ) {
                 e.preventDefault();
-                handleSend();
+                sendMessage();
               }
             }}
             onPaste={onPasteIntoComposer}
@@ -647,7 +1247,7 @@ function MyChatPanel({ workspaceId, data }: Props) {
             className="flex-1 bg-surface-card border border-line rounded-lg px-3 py-2 text-xs text-ink placeholder-ink-soft dark:bg-zinc-800 dark:border-zinc-600 dark:placeholder-zinc-500 focus:outline-none focus:border-accent focus-visible:ring-2 focus-visible:ring-accent/40 resize-none disabled:opacity-50"
           />
           <button
-            onClick={handleSend}
+            onClick={sendMessage}
             disabled={(!input.trim() && pendingFiles.length === 0) || !agentReachable || sending || uploading}
             className="px-4 py-2 bg-accent-strong hover:bg-accent text-xs font-medium rounded-lg text-white disabled:opacity-30 transition-colors shrink-0"
           >

canvas/src/components/tabs/chat/hooks/index.ts

@@ -1,3 +0,0 @@
-export { useChatHistory } from "./useChatHistory";
-export { useChatSend } from "./useChatSend";
-export { useChatSocket } from "./useChatSocket";

canvas/src/components/tabs/chat/hooks/resolveWorkspaceName.ts

@@ -1,11 +0,0 @@
-"use client";
-
-import { useCanvasStore, type WorkspaceNodeData } from "@/store/canvas";
-
-/** Resolve a workspace ID to its human-readable name.
- *  Falls back to the first 8 chars of the ID. */
-export function resolveWorkspaceName(id: string): string {
-  const nodes = useCanvasStore.getState().nodes;
-  const node = nodes.find((n) => n.id === id);
-  return (node?.data as WorkspaceNodeData)?.name || id.slice(0, 8);
-}

canvas/src/components/tabs/chat/hooks/useChatHistory.ts

@@ -1,134 +0,0 @@
-"use client";
-
-import { useCallback, useEffect, useRef, useState } from "react";
-import { api } from "@/lib/api";
-import { type ChatMessage, appendMessageDeduped as appendMessageDedupedFn } from "../types";
-
-const INITIAL_HISTORY_LIMIT = 10;
-const OLDER_HISTORY_BATCH = 20;
-
-async function loadMessagesFromDB(
-  workspaceId: string,
-  limit: number,
-  beforeTs?: string,
-): Promise<{ messages: ChatMessage[]; error: string | null; reachedEnd: boolean }> {
-  try {
-    const params = new URLSearchParams({ limit: String(limit) });
-    if (beforeTs) params.set("before_ts", beforeTs);
-    const resp = await api.get<{ messages: ChatMessage[]; reached_end: boolean }>(
-      `/workspaces/${workspaceId}/chat-history?${params.toString()}`,
-    );
-    return {
-      messages: resp.messages ?? [],
-      error: null,
-      reachedEnd: resp.reached_end,
-    };
-  } catch (err) {
-    return {
-      messages: [],
-      error: err instanceof Error ? err.message : "Failed to load chat history",
-      reachedEnd: true,
-    };
-  }
-}
-
-export interface ScrollAnchor {
-  savedDistanceFromBottom: number;
-  expectFirstIdNotEqual: string | null;
-}
-
-export function useChatHistory(
-  workspaceId: string,
-  containerRef?: React.RefObject<HTMLDivElement | null>,
-) {
-  const [messages, setMessages] = useState<ChatMessage[]>([]);
-  const [loading, setLoading] = useState(true);
-  const [loadError, setLoadError] = useState<string | null>(null);
-  const [loadingOlder, setLoadingOlder] = useState(false);
-  const [hasMore, setHasMore] = useState(true);
-
-  const fetchTokenRef = useRef(0);
-  const oldestMessageRef = useRef<ChatMessage | null>(null);
-  const hasMoreRef = useRef(true);
-  const inflightRef = useRef(false);
-  const scrollAnchorRef = useRef<ScrollAnchor | null>(null);
-
-  useEffect(() => {
-    oldestMessageRef.current = messages[0] ?? null;
-  }, [messages]);
-
-  useEffect(() => {
-    hasMoreRef.current = hasMore;
-  }, [hasMore]);
-
-  const loadInitial = useCallback(() => {
-    setLoading(true);
-    setLoadError(null);
-    setHasMore(true);
-    fetchTokenRef.current += 1;
-    const myToken = fetchTokenRef.current;
-    return loadMessagesFromDB(workspaceId, INITIAL_HISTORY_LIMIT).then(
-      ({ messages: msgs, error: fetchErr, reachedEnd }) => {
-        if (fetchTokenRef.current !== myToken) return;
-        setMessages(msgs);
-        setLoadError(fetchErr);
-        setHasMore(!reachedEnd);
-        setLoading(false);
-      },
-    );
-  }, [workspaceId]);
-
-  useEffect(() => {
-    loadInitial();
-  }, [loadInitial]);
-
-  const loadOlder = useCallback(async () => {
-    if (inflightRef.current || !hasMoreRef.current) return;
-    const oldest = oldestMessageRef.current;
-    if (!oldest) return;
-    const container = containerRef?.current;
-    if (!container) return;
-    inflightRef.current = true;
-    scrollAnchorRef.current = {
-      savedDistanceFromBottom: container.scrollHeight - container.scrollTop,
-      expectFirstIdNotEqual: oldest.id,
-    };
-    fetchTokenRef.current += 1;
-    const myToken = fetchTokenRef.current;
-    setLoadingOlder(true);
-    try {
-      const { messages: older, reachedEnd } = await loadMessagesFromDB(
-        workspaceId,
-        OLDER_HISTORY_BATCH,
-        oldest.timestamp,
-      );
-      if (fetchTokenRef.current !== myToken) {
-        scrollAnchorRef.current = null;
-        return;
-      }
-      if (older.length > 0) {
-        setMessages((prev) => [...older, ...prev]);
-      } else {
-        scrollAnchorRef.current = null;
-      }
-      setHasMore(!reachedEnd);
-    } finally {
-      setLoadingOlder(false);
-      inflightRef.current = false;
-    }
-  }, [workspaceId, containerRef]);
-
-  return {
-    messages,
-    loading,
-    loadError,
-    loadingOlder,
-    hasMore,
-    loadInitial,
-    loadOlder,
-    appendMessageDeduped: (msg: ChatMessage) =>
-      setMessages((prev) => appendMessageDedupedFn(prev, msg)),
-    setMessages,
-    scrollAnchorRef,
-  };
-}

canvas/src/components/tabs/chat/hooks/useChatSend.ts

@@ -1,182 +0,0 @@
-"use client";
-
-import { useCallback, useRef, useState } from "react";
-import { api } from "@/lib/api";
-import { uploadChatFiles } from "../uploads";
-import { createMessage, type ChatMessage, type ChatAttachment } from "../types";
-import { extractFilesFromTask } from "../message-parser";
-
-interface A2APart {
-  kind: string;
-  text?: string;
-  file?: {
-    name?: string;
-    mimeType?: string;
-    uri?: string;
-    size?: number;
-  };
-}
-
-interface A2AResponse {
-  result?: {
-    parts?: A2APart[];
-    artifacts?: Array<{ parts: A2APart[] }>;
-  };
-}
-
-export function extractReplyText(resp: A2AResponse): string {
-  const collect = (parts: A2APart[] | undefined): string => {
-    if (!parts) return "";
-    return parts
-      .filter((p) => p.kind === "text")
-      .map((p) => p.text ?? "")
-      .filter(Boolean)
-      .join("\n");
-  };
-  const result = resp?.result;
-  const collected: string[] = [];
-  const fromParts = collect(result?.parts);
-  if (fromParts) collected.push(fromParts);
-  if (result?.artifacts) {
-    for (const a of result.artifacts) {
-      const t = collect(a.parts);
-      if (t) collected.push(t);
-    }
-  }
-  return collected.join("\n");
-}
-
-export interface UseChatSendOptions {
-  getHistoryMessages: () => ChatMessage[];
-  onUserMessage?: (msg: ChatMessage) => void;
-  onAgentMessage?: (msg: ChatMessage) => void;
-}
-
-export function useChatSend(workspaceId: string, options: UseChatSendOptions) {
-  const [sending, setSending] = useState(false);
-  const [uploading, setUploading] = useState(false);
-  const [error, setError] = useState<string | null>(null);
-  const sendInFlightRef = useRef(false);
-  const sendingFromAPIRef = useRef(false);
-  const sendTokenRef = useRef(0);
-  const optionsRef = useRef(options);
-  optionsRef.current = options;
-
-  const releaseSendGuards = useCallback(() => {
-    setSending(false);
-    sendingFromAPIRef.current = false;
-    sendInFlightRef.current = false;
-  }, []);
-
-  const clearError = useCallback(() => setError(null), []);
-
-  const sendMessage = useCallback(
-    async (text: string, files: File[] = []) => {
-      const trimmed = text.trim();
-      if ((!trimmed && files.length === 0) || sending || uploading) return;
-      if (sendInFlightRef.current) return;
-      sendInFlightRef.current = true;
-
-      let uploaded: ChatAttachment[] = [];
-      if (files.length > 0) {
-        setUploading(true);
-        try {
-          uploaded = await uploadChatFiles(workspaceId, files);
-        } catch (e) {
-          setUploading(false);
-          sendInFlightRef.current = false;
-          setError(
-            e instanceof Error ? `Upload failed: ${e.message}` : "Upload failed",
-          );
-          return;
-        }
-        setUploading(false);
-      }
-
-      const userMsg = createMessage("user", trimmed, uploaded);
-      optionsRef.current.onUserMessage?.(userMsg);
-
-      setSending(true);
-      sendingFromAPIRef.current = true;
-      setError(null);
-      const myToken = ++sendTokenRef.current;
-
-      const history = optionsRef.current
-        .getHistoryMessages()
-        .filter((m) => m.role === "user" || m.role === "agent")
-        .slice(-20)
-        .map((m) => ({
-          role: m.role === "user" ? "user" : "agent",
-          parts: [{ kind: "text", text: m.content }],
-        }));
-
-      const parts: A2APart[] = [];
-      if (trimmed) parts.push({ kind: "text", text: trimmed });
-      for (const att of uploaded) {
-        parts.push({
-          kind: "file",
-          file: {
-            name: att.name,
-            mimeType: att.mimeType,
-            uri: att.uri,
-            size: att.size,
-          },
-        });
-      }
-
-      api
-        .post<A2AResponse>(
-          `/workspaces/${workspaceId}/a2a`,
-          {
-            method: "message/send",
-            params: {
-              message: {
-                role: "user",
-                messageId: crypto.randomUUID(),
-                parts,
-              },
-              metadata: { history },
-            },
-          },
-          { timeoutMs: 120_000 },
-        )
-        .then((resp) => {
-          if (sendTokenRef.current !== myToken) return;
-          if (!sendingFromAPIRef.current) {
-            sendInFlightRef.current = false;
-            return;
-          }
-          const replyText = extractReplyText(resp);
-          const replyFiles = extractFilesFromTask(
-            (resp?.result ?? {}) as Record<string, unknown>,
-          );
-          if (replyText || replyFiles.length > 0) {
-            optionsRef.current.onAgentMessage?.(
-              createMessage("agent", replyText, replyFiles),
-            );
-          }
-          releaseSendGuards();
-        })
-        .catch(() => {
-          if (sendTokenRef.current !== myToken) return;
-          if (!sendingFromAPIRef.current) {
-            sendInFlightRef.current = false;
-            return;
-          }
-          releaseSendGuards();
-          setError("Failed to send message — agent may be unreachable");
-        });
-    },
-    [workspaceId, sending, uploading],
-  );
-
-  return {
-    sending,
-    uploading,
-    sendMessage,
-    error,
-    clearError,
-    releaseSendGuards,
-    sendingFromAPIRef,
-  };
-}

canvas/src/components/tabs/chat/hooks/useChatSocket.ts

@@ -1,100 +0,0 @@
-"use client";
-
-import { useCallback, useEffect, useRef } from "react";
-import { useCanvasStore, type WorkspaceNodeData } from "@/store/canvas";
-import { useSocketEvent } from "@/hooks/useSocketEvent";
-import { createMessage, type ChatMessage } from "../types";
-
-export interface UseChatSocketCallbacks {
-  onAgentMessage?: (msg: ChatMessage) => void;
-  onActivityLog?: (entry: string) => void;
-  onSendComplete?: () => void;
-  onSendError?: (error: string) => void;
-}
-
-export function useChatSocket(
-  workspaceId: string,
-  callbacks: UseChatSocketCallbacks,
-): void {
-  const callbacksRef = useRef(callbacks);
-  callbacksRef.current = callbacks;
-
-  // Agent push messages from global store
-  const pendingAgentMsgs = useCanvasStore((s) => s.agentMessages[workspaceId]);
-  useEffect(() => {
-    if (!pendingAgentMsgs || pendingAgentMsgs.length === 0) return;
-    const consume = useCanvasStore.getState().consumeAgentMessages;
-    const msgs = consume(workspaceId);
-    for (const m of msgs) {
-      callbacksRef.current.onAgentMessage?.(
-        createMessage("agent", m.content, m.attachments),
-      );
-    }
-    if (msgs.length > 0) {
-      callbacksRef.current.onSendComplete?.();
-    }
-  }, [pendingAgentMsgs, workspaceId]);
-
-  const resolveWorkspaceName = useCallback((id: string) => {
-    const nodes = useCanvasStore.getState().nodes;
-    const node = nodes.find((n) => n.id === id);
-    return (node?.data as WorkspaceNodeData)?.name || id.slice(0, 8);
-  }, []);
-
-  useSocketEvent((msg) => {
-    try {
-      if (msg.event === "ACTIVITY_LOGGED") {
-        if (msg.workspace_id !== workspaceId) return;
-
-        const p = msg.payload || {};
-        const type = p.activity_type as string;
-        const method = (p.method as string) || "";
-        const status = (p.status as string) || "";
-        const targetId = (p.target_id as string) || "";
-        const durationMs = p.duration_ms as number | undefined;
-        const summary = (p.summary as string) || "";
-
-        let line = "";
-        if (type === "a2a_receive" && method === "message/send") {
-          const targetName = resolveWorkspaceName(targetId || msg.workspace_id);
-          if (status === "ok" && durationMs) {
-            const sec = Math.round(durationMs / 1000);
-            line = `← ${targetName} responded (${sec}s)`;
-            const own = (targetId || msg.workspace_id) === workspaceId;
-            if (own) callbacksRef.current.onSendComplete?.();
-          } else if (status === "error") {
-            line = `⚠ ${targetName} error`;
-            const own = (targetId || msg.workspace_id) === workspaceId;
-            if (own) {
-              callbacksRef.current.onSendComplete?.();
-              callbacksRef.current.onSendError?.(
-                "Agent error (Exception) — see workspace logs for details.",
-              );
-            }
-          }
-        } else if (type === "a2a_send") {
-          const targetName = resolveWorkspaceName(targetId);
-          line = `→ Delegating to ${targetName}...`;
-        } else if (type === "task_update") {
-          if (summary) line = `⟳ ${summary}`;
-        } else if (type === "agent_log") {
-          if (summary) line = summary;
-        }
-
-        if (line) {
-          callbacksRef.current.onActivityLog?.(line);
-        }
-      } else if (
-        msg.event === "TASK_UPDATED" &&
-        msg.workspace_id === workspaceId
-      ) {
-        const task = (msg.payload?.current_task as string) || "";
-        if (task) {
-          callbacksRef.current.onActivityLog?.(`⟳ ${task}`);
-        }
-      }
-    } catch {
-      /* ignore */
-    }
-  });
-}

canvas/src/components/tabs/chat/index.ts

@@ -1,5 +1,2 @@
 export { type ChatMessage, createMessage, appendMessageDeduped } from "./types";
 export { extractAgentText, extractTextsFromParts, extractResponseText } from "./message-parser";
-export { useChatHistory } from "./hooks/useChatHistory";
-export { useChatSend } from "./hooks/useChatSend";
-export { useChatSocket } from "./hooks/useChatSocket";

workspace-server/internal/handlers/external_connection.go

@@ -225,7 +225,7 @@ const externalUniversalMcpTemplate = `# Universal MCP — standalone register +
 # python3.12 / etc.) or use a 3.11+ venv.
 
 # 1. Install the workspace runtime wheel:
-pip install molecule-ai-workspace-runtime
+pip install "molecule-ai-workspace-runtime>=0.1.999"
 
 # 2. Wire molecule-mcp into your agent's MCP config. Claude Code:
 claude mcp add molecule -s user -- env \
@@ -336,7 +336,7 @@ const externalHermesChannelTemplate = `# Hermes channel — bridges this workspa
 # also supported via the plugin's dual-mode fallback.
 #
 # 1. Install the runtime + plugin:
-pip install molecule-ai-workspace-runtime
+pip install "molecule-ai-workspace-runtime>=0.1.999"
 pip install 'git+https://git.moleculesai.app/molecule-ai/hermes-channel-molecule.git'
 
 # 2. Export the workspace credentials:
@@ -407,7 +407,7 @@ const externalCodexTemplate = `# Codex external setup — outbound tools (MCP) +
 
 # 1. Install codex CLI, the workspace runtime, and the bridge daemon:
 npm install -g @openai/codex@latest
-pip install molecule-ai-workspace-runtime
+pip install "molecule-ai-workspace-runtime>=0.1.999"
 pip install codex-channel-molecule
 
 # 2. Wire the molecule MCP server into codex's config.toml — this is
@@ -499,7 +499,7 @@ const externalKimiTemplate = `# Kimi CLI external setup — register + heartbeat
 # No public URL needed; runs behind NAT in poll mode.
 
 # 1. Install the workspace runtime wheel (provides HTTP client):
-pip install molecule-ai-workspace-runtime
+pip install "molecule-ai-workspace-runtime>=0.1.999"
 
 # 2. Save credentials and the bridge script:
 mkdir -p ~/.molecule-ai/kimi-workspace
@@ -647,7 +647,7 @@ const externalOpenClawTemplate = `# OpenClaw MCP config — outbound tool path.
 
 # 1. Install openclaw CLI + the workspace runtime wheel:
 npm install -g openclaw@latest
-pip install molecule-ai-workspace-runtime
+pip install "molecule-ai-workspace-runtime>=0.1.999"
 
 # 2. Onboard openclaw against your model provider (one-time setup).
 #    --non-interactive needs an explicit --provider + --model so it