fix(desktop): trigger slash command preview only at the start of a message

apps/desktop/src/app/chat/composer/index.tsx

@@ -1035,8 +1035,16 @@ export function ChatBar({
   }, [activeQueueSessionKey, editingQueuedPrompt, queueEdit]) // eslint-disable-line react-hooks/exhaustive-deps
 
   const submitDraft = () => {
+    const trimmedDraft = draft.trim()
+
     if (queueEdit) {
       exitQueuedEdit('save')
+    } else if (trimmedDraft && SLASH_COMMAND_RE.test(trimmedDraft) && !attachments.length) {
+      // Slash commands are dispatched immediately (via onSubmit →
+      // executeSlashCommand), never queued — even when busy.
+      triggerHaptic('submit')
+      clearDraft()
+      void onSubmit(trimmedDraft)
     } else if (busy) {
       // Slash commands should execute immediately even while the agent is
       // busy — they're client-side operations (/yolo, /skin, /new, /help,
@@ -1045,7 +1053,7 @@ export function ChatBar({
       // busy guard for commands that genuinely need an idle session (skill
       // /send directives).  Queuing them would make every slash command wait
       // for the current turn to finish, which is how the TUI never behaves.
-      if (!attachments.length && SLASH_COMMAND_RE.test(draft.trim())) {
+      if (!attachments.length && trimmedDraft) {
         const submitted = draft
         triggerHaptic('submit')
         clearDraft()
@@ -1064,7 +1072,7 @@ export function ChatBar({
       }
     } else if (!hasComposerPayload && queuedPrompts.length > 0) {
       void drainNextQueued()
-    } else if (draft.trim() || attachments.length > 0) {
+    } else if (trimmedDraft || attachments.length > 0) {
       const submitted = draft
       triggerHaptic('submit')
       clearDraft()

apps/desktop/src/app/chat/composer/text-utils.test.ts

@@ -75,3 +75,58 @@ describe('blobDedupeKey', () => {
     expect(blobDedupeKey(file)).toBe('file:a.png:0:image/png:42')
   })
 })
+
+
+describe('detectTrigger', () => {
+  it('detects slash commands at the start of the input', () => {
+    const result = detectTrigger('/steer')
+    expect(result).toEqual({ kind: '/', query: 'steer', tokenLength: 6 })
+  })
+
+  it('detects partial slash commands at the start', () => {
+    const result = detectTrigger('/st')
+    expect(result).toEqual({ kind: '/', query: 'st', tokenLength: 3 })
+  })
+
+  it('detects bare slash at the start', () => {
+    const result = detectTrigger('/')
+    expect(result).toEqual({ kind: '/', query: '', tokenLength: 1 })
+  })
+
+  it('does NOT trigger slash autocomplete mid-message', () => {
+    const result = detectTrigger('hello /steer')
+    expect(result).toBeNull()
+  })
+
+  it('does NOT trigger slash autocomplete after a space mid-message', () => {
+    const result = detectTrigger('some text /new')
+    expect(result).toBeNull()
+  })
+
+  it('detects @ mentions at the start of the input', () => {
+    const result = detectTrigger('@user')
+    expect(result).toEqual({ kind: '@', query: 'user', tokenLength: 5 })
+  })
+
+  it('detects @ mentions mid-sentence after whitespace', () => {
+    const result = detectTrigger('hello @user')
+    expect(result).toEqual({ kind: '@', query: 'user', tokenLength: 5 })
+  })
+
+  it('detects @ mentions at the start of a new line', () => {
+    const result = detectTrigger('hello\n@user')
+    expect(result).toEqual({ kind: '@', query: 'user', tokenLength: 5 })
+  })
+
+  it('returns null for plain text without triggers', () => {
+    expect(detectTrigger('hello world')).toBeNull()
+  })
+
+  it('returns null for empty input', () => {
+    expect(detectTrigger('')).toBeNull()
+  })
+
+  it('returns null when / is embedded in a word mid-message', () => {
+    expect(detectTrigger('use path/to/file')).toBeNull()
+  })
+})

apps/desktop/src/app/chat/composer/text-utils.ts

@@ -6,7 +6,10 @@ export interface TriggerState {
   tokenLength: number
 }
 
-const TRIGGER_RE = /(?:^|[\s])([@/])([^\s@/]*)$/
+// Slash commands only trigger autocomplete at the start of the input;
+// @ mentions can appear mid-sentence after whitespace.
+const SLASH_TRIGGER_RE = /^\/([^\s@/]*)$/
+const AT_TRIGGER_RE = /(?:^|[\s])@([^\s@/]*)$/
 
 /** Stable key for paste dedupe — `items` and `files` often mirror the same image as different objects. */
 export function blobDedupeKey(blob: Blob): string {
@@ -97,11 +100,17 @@ export function textBeforeCaret(editor: HTMLDivElement): string | null {
 }
 
 export function detectTrigger(textBefore: string): TriggerState | null {
-  const match = TRIGGER_RE.exec(textBefore)
+  const slashMatch = SLASH_TRIGGER_RE.exec(textBefore)
 
-  if (!match) {
-    return null
+  if (slashMatch) {
+    return { kind: '/', query: slashMatch[1], tokenLength: 1 + slashMatch[1].length }
   }
 
-  return { kind: match[1] as '@' | '/', query: match[2], tokenLength: 1 + match[2].length }
+  const atMatch = AT_TRIGGER_RE.exec(textBefore)
+
+  if (atMatch) {
+    return { kind: '@', query: atMatch[1], tokenLength: 1 + atMatch[1].length }
+  }
+
+  return null
 }