fix(clients): align placeholders with conversation state

apps/mobile/src/features/threads/NewTaskDraftScreen.tsx

@@ -16,6 +16,7 @@ import {
   isAtomCommandInterrupted,
   squashAtomCommandFailure,
 } from "@t3tools/client-runtime/state/runtime";
+import { conversationComposerPlaceholder } from "@t3tools/client-runtime/composer";
 
 import { ComposerEditor, type ComposerEditorHandle } from "../../components/ComposerEditor";
 import {
@@ -896,7 +897,7 @@ export function NewTaskDraftScreen(props: {
       onFocus={() => setIsComposerFocused(true)}
       onBlur={() => setIsComposerFocused(false)}
       onPasteImages={(uris) => void handleNativePasteImages(uris)}
-      placeholder={`Describe a coding task in ${selectedProject.title}`}
+      placeholder={conversationComposerPlaceholder("new")}
       // Same collapsed centering as ThreadComposer: native vertical gravity
       // in a pill-height box.
       singleLineCentered={!isExpanded}

apps/mobile/src/features/threads/ThreadDetailScreen.tsx

@@ -53,6 +53,7 @@ import Animated, {
 import { useSafeAreaInsets } from "react-native-safe-area-context";
 
 import { ControlPill } from "../../components/ControlPill";
+import { conversationComposerPlaceholder } from "@t3tools/client-runtime/composer";
 import type { ComposerEditorHandle } from "../../components/ComposerEditor";
 import type { StatusTone } from "../../components/StatusPill";
 import type { DraftComposerImageAttachment } from "../../lib/composerImages";
@@ -717,7 +718,7 @@ export const ThreadDetailScreen = memo(function ThreadDetailScreen(props: Thread
                 editorRef={composerEditorRef}
                 draftMessage={props.draftMessage}
                 draftAttachments={props.draftAttachments}
-                placeholder="Ask the repo agent, or run a command…"
+                placeholder={conversationComposerPlaceholder("existing")}
                 contentMaxWidth={contentMaxWidth}
                 connectionState={props.connectionStateLabel}
                 connectionError={props.connectionError}

apps/web/src/components/ChatView.logic.test.ts

@@ -15,6 +15,7 @@ import {
   branchMismatchKey,
   buildExpiredTerminalContextToastCopy,
   buildLoadingThreadFromShell,
+  resolveComposerConversationKind,
   buildThreadTurnInterruptInput,
   createLocalDispatchSnapshot,
   deriveComposerSendState,
@@ -170,6 +171,18 @@ describe("buildLoadingThreadFromShell", () => {
   });
 });
 
+describe("resolveComposerConversationKind", () => {
+  it("preserves existing-thread guidance while message detail is loading", () => {
+    expect(
+      resolveComposerConversationKind({
+        messageCount: 0,
+        threadDetailLoading: true,
+        latestUserMessageAt: now,
+      }),
+    ).toBe("existing");
+  });
+});
+
 describe("resolveThreadMetadataUpdateForNextTurn", () => {
   const modelSelection = {
     instanceId: ProviderInstanceId.make("codex"),

apps/web/src/components/ChatView.logic.ts

@@ -10,6 +10,7 @@ import {
   type ThreadId,
   type TurnId,
 } from "@t3tools/contracts";
+import type { ComposerConversationKind } from "@t3tools/client-runtime/composer";
 import { type ChatMessage, type SessionPhase, type Thread, type ThreadShell } from "../types";
 import { type ComposerImageAttachment, type DraftThreadState } from "../composerDraftStore";
 import * as Schema from "effect/Schema";
@@ -119,6 +120,16 @@ export function buildLoadingThreadFromShell(shell: ThreadShell): Thread {
   };
 }
 
+export function resolveComposerConversationKind(input: {
+  readonly messageCount: number;
+  readonly threadDetailLoading: boolean;
+  readonly latestUserMessageAt: string | null;
+}): ComposerConversationKind {
+  return input.messageCount > 0 || (input.threadDetailLoading && input.latestUserMessageAt !== null)
+    ? "existing"
+    : "new";
+}
+
 export function shouldWriteThreadErrorToCurrentServerThread(input: {
   activeServerThread:
     | {

apps/web/src/components/ChatView.tsx

@@ -289,6 +289,7 @@ import {
   buildExpiredTerminalContextToastCopy,
   buildLocalDraftThread,
   buildLoadingThreadFromShell,
+  resolveComposerConversationKind,
   buildThreadTurnInterruptInput,
   collectUserMessageBlobPreviewUrls,
   createLocalDispatchSnapshot,
@@ -2548,6 +2549,11 @@ function ChatViewContent(props: ChatViewProps) {
       ),
     [activeThread?.proposedPlans, timelineMessages, turnPlans, workLogEntries],
   );
+  const composerConversationKind = resolveComposerConversationKind({
+    messageCount: timelineMessages.length,
+    threadDetailLoading,
+    latestUserMessageAt: routeServerThreadShell?.latestUserMessageAt ?? null,
+  });
   const [dockedDraftHeroThreadKey, setDockedDraftHeroThreadKey] = useState<string | null>(null);
   const draftHeroDockRequested =
     activeThreadKey !== null && dockedDraftHeroThreadKey === activeThreadKey;
@@ -6344,6 +6350,7 @@ function ChatViewContent(props: ChatViewProps) {
                             activeThread={activeThread}
                             isServerThread={isServerThread}
                             isLocalDraftThread={isLocalDraftThread}
+                            conversationKind={composerConversationKind}
                             forceExpandedOnMobile={forceExpandedMobileComposer && isDraftHeroState}
                             projectSelectionRequired={isLocalDraftThread && activeProject === null}
                             phase={phase}

apps/web/src/components/chat/ChatComposer.tsx

@@ -18,6 +18,10 @@ import {
   PROVIDER_SEND_TURN_MAX_IMAGE_BYTES,
 } from "@t3tools/contracts";
 import type { EnvironmentConnectionPresentation } from "@t3tools/client-runtime/connection";
+import {
+  conversationComposerPlaceholder,
+  type ComposerConversationKind,
+} from "@t3tools/client-runtime/composer";
 import { serializeComposerFileLink } from "@t3tools/shared/composerTrigger";
 import { createModelSelection, normalizeModelSlug } from "@t3tools/shared/model";
 import {
@@ -503,6 +507,7 @@ export interface ChatComposerProps {
   activeThread: Thread | undefined;
   isServerThread: boolean;
   isLocalDraftThread: boolean;
+  conversationKind: ComposerConversationKind;
   forceExpandedOnMobile: boolean;
   projectSelectionRequired: boolean;
 
@@ -612,6 +617,7 @@ export const ChatComposer = memo(function ChatComposer(props: ChatComposerProps)
     activeThread,
     isServerThread: _isServerThread,
     isLocalDraftThread: _isLocalDraftThread,
+    conversationKind,
     forceExpandedOnMobile,
     projectSelectionRequired,
     phase,
@@ -3049,9 +3055,7 @@ export const ChatComposer = memo(function ChatComposer(props: ChatComposerProps)
                           ? "Choose a project above to start a thread"
                           : noProviderAvailable
                             ? "Enable a provider in Settings to send a message"
-                            : phase === "disconnected"
-                              ? "Ask for follow-up changes or attach images"
-                              : "Ask anything, @tag files/folders, $use skills, or / for commands"
+                            : conversationComposerPlaceholder(conversationKind)
                 }
                 disabled={isConnecting || isComposerApprovalState || projectSelectionRequired}
               />

apps/web/src/components/settings/SettingsFontPreviews.tsx

@@ -1,4 +1,5 @@
 import { preloadPatchFile } from "@pierre/diffs/ssr";
+import { conversationComposerPlaceholder } from "@t3tools/client-runtime/composer";
 import { useCallback, useEffect, useRef, useState } from "react";
 import { ComposerPromptEditor, type ComposerPromptEditorHandle } from "../ComposerPromptEditor";
 import { terminalThemeFromApp } from "../ThreadTerminalDrawer";
@@ -43,7 +44,7 @@ export function PromptFontPreview() {
         terminalContexts={EMPTY_TERMINAL_CONTEXTS}
         skills={EMPTY_SKILLS}
         disabled={false}
-        placeholder="Ask for follow-up changes or attach images"
+        placeholder={conversationComposerPlaceholder("new")}
         className="max-h-40 min-h-12"
         onRemoveTerminalContext={noop}
         onChange={onChange}

packages/client-runtime/package.json

@@ -3,6 +3,10 @@
   "private": true,
   "type": "module",
   "exports": {
+    "./composer": {
+      "types": "./src/composer.ts",
+      "default": "./src/composer.ts"
+    },
     "./connection": {
       "types": "./src/connection/index.ts",
       "default": "./src/connection/index.ts"

packages/client-runtime/src/composer.ts

@@ -0,0 +1,11 @@
+export type ComposerConversationKind = "new" | "existing";
+
+const CONVERSATION_PLACEHOLDERS = {
+  new: "Describe the task, tag @files, use $skills or /commands",
+  existing: "Ask for changes, add context, or attach images",
+} as const satisfies Record<ComposerConversationKind, string>;
+
+/** Returns the ordinary composer guidance shared by web, desktop, and mobile. */
+export function conversationComposerPlaceholder(kind: ComposerConversationKind) {
+  return CONVERSATION_PLACEHOLDERS[kind];
+}