Fix

1. engine.beginGeneration() — clears the abort latch at the start of each send
2. Stop unlocks the UI immediately — increments a runId, shows Send again, status: “Stopped — ready for a new message”
3. In-flight turn is invalidated — late stream/tool updates ignore a superseded run
4. New chat — stops any busy turn and resets the same way
5. Cancel timeout — IPC cancel won’t hang Stop for more than ~2.5s

ui/qvac/engine.js

@@ -103,13 +103,18 @@ export function createQvacEngine(deps) {
   /**
    * Stop in-flight inference (and pending tool rounds).
    * Safe to call when idle.
+   * Leaves abort latch set until {@link beginGeneration} (start of next send).
    */
   async function stop() {
     abortGeneration = true
     const ipc = getElectronIpc()
     try {
       if (ipc && sdkMode === 'main') {
-        await ipc.invoke('peardata:qvac-cancel')
+        // Don't hang the UI if cancel is slow — race a short timeout
+        await Promise.race([
+          ipc.invoke('peardata:qvac-cancel'),
+          new Promise((r) => setTimeout(r, 2500)),
+        ])
       } else if (sdk?.cancel) {
         if (activeRequestId) {
           try {
@@ -136,6 +141,12 @@ export function createQvacEngine(deps) {
     return abortGeneration
   }
 
+  /** Clear stop latch — call at the start of each user send. */
+  function beginGeneration() {
+    abortGeneration = false
+    activeRequestId = null
+  }
+
   /** @type {any} */
   let sdk = null
   /** @type {'direct'|'main'|null} */
@@ -483,6 +494,8 @@ export function createQvacEngine(deps) {
    */
   async function complete(history, opts = {}) {
     touchActivity()
+    // Fresh generation for this complete() call (stop during prior turns is cleared).
+    // UI also calls beginGeneration() at send start so multi-agent can run before this.
     abortGeneration = false
     const profile = getProfile(profileId || 'recommended')
     const prefs = deps.getPrefs?.() || {}
@@ -873,6 +886,7 @@ export function createQvacEngine(deps) {
     complete,
     stop,
     isAborted,
+    beginGeneration,
     getStatus,
     tryLoadSdk,
     touchActivity,

ui/qvac/index.js

@@ -112,6 +112,8 @@ export function createQvacView(opts) {
   /** @type {Array<{ role: string, content: string, tools?: any[] }>} */
   let messages = []
   let busy = false
+  /** Invalidates in-flight send when Stop is pressed so UI unlocks immediately. */
+  let runId = 0
   let wizardStep = 0
   /** @type {string} */
   let selectedProfile = 'recommended'
@@ -809,6 +811,17 @@ export function createQvacView(opts) {
     }
   }
 
+  /**
+   * Unlock composer after Stop even if the in-flight send is still winding down.
+   * Also clears the abort latch only after a new send begins (see beginGeneration).
+   */
+  function finishStoppedUi() {
+    runId += 1
+    setBusyUi(false)
+    setStatus('Stopped — ready for a new message', 'warn')
+    syncModelChip()
+  }
+
   async function stopInference() {
     if (!busy) return
     setStatus('Stopping…', 'busy')
@@ -818,6 +831,8 @@ export function createQvacView(opts) {
     } catch (err) {
       opts.log?.(`QVAC stop: ${err?.message || err}`)
     }
+    // Always re-enable chat immediately — do not wait for hung tools / stream
+    finishStoppedUi()
   }
 
   async function send() {
@@ -825,6 +840,9 @@ export function createQvacView(opts) {
     const text = (input?.value || '').trim()
     if (!text || busy) return
     if (input) input.value = ''
+    // Clear previous Stop latch so this turn can run
+    engine.beginGeneration?.()
+    const myRun = ++runId
     setBusyUi(true)
     appendMsg('user', text)
     const assistantUi = appendMsg('assistant', '…', { streaming: true })
@@ -837,6 +855,7 @@ export function createQvacView(opts) {
     // Hide legacy sticky bar if still in DOM
     opts.els.agentBar?.classList.add('hidden')
     opts.els.agentBar && (opts.els.agentBar.innerHTML = '')
+    const stillThisRun = () => myRun === runId
     try {
       // History for the model: clean answers only (no think tags)
       const hist = messages
@@ -894,11 +913,13 @@ export function createQvacView(opts) {
             followMessagesScroll()
           },
         })
-        if (engine.isAborted?.()) {
+        if (engine.isAborted?.() || !stillThisRun()) {
-          swarm.fail('Stopped')
+          if (stillThisRun()) {
-          acc = '_(Stopped during multi-agent investigation.)_'
+            swarm.fail('Stopped')
-          paintAssistant(streamBody, acc, false)
+            acc = '_(Stopped during multi-agent investigation.)_'
-          setStatus('Stopped', 'warn')
+            paintAssistant(streamBody, acc, false)
+            setStatus('Stopped — ready for a new message', 'warn')
+          }
           return
         }
         swarm.complete('All agents done — synthesizing answer…')
@@ -929,20 +950,24 @@ export function createQvacView(opts) {
         followMessagesScroll({ force: true })
       }
 
-      if (engine.isAborted?.()) {
+      if (engine.isAborted?.() || !stillThisRun()) {
-        acc = '_(Stopped.)_'
+        if (stillThisRun()) {
-        paintAssistant(streamBody, acc, false)
+          acc = '_(Stopped.)_'
-        setStatus('Stopped', 'warn')
+          paintAssistant(streamBody, acc, false)
+          setStatus('Stopped — ready for a new message', 'warn')
+        }
         return
       }
 
       const result = await engine.complete(hist, {
         ...completeOpts,
         onToken: (t) => {
+          if (!stillThisRun()) return
           acc += t
           paintAssistant(streamBody, mergeThinkStream(thinkingAcc, acc), true)
         },
         onThinking: (t) => {
+          if (!stillThisRun()) return
           thinkingAcc += t
           const raw = thinkingAcc
             ? `<think>\n${thinkingAcc}\n</think>\n${acc}`
@@ -950,7 +975,7 @@ export function createQvacView(opts) {
           paintAssistant(streamBody, raw, true)
         },
         onTool: (name, args, res) => {
-          if (engine.isAborted?.()) return
+          if (engine.isAborted?.() || !stillThisRun()) return
           toolLog.push({ name, args, result: res })
           setStatus(`Tool: ${name}…`, 'busy')
           if (assistantUi?.div) {
@@ -961,6 +986,7 @@ export function createQvacView(opts) {
           }
         },
       })
+      if (!stillThisRun()) return
       acc = result.contentText || acc
       if (thinkingAcc && !/<think/i.test(acc)) {
         acc = `<think>\n${thinkingAcc}\n</think>\n${acc}`
@@ -1004,11 +1030,12 @@ export function createQvacView(opts) {
         }
       }
       if (result.stopped || result.mode === 'stopped') {
-        setStatus('Stopped', 'warn')
+        setStatus('Stopped — ready for a new message', 'warn')
       } else {
         setStatus(result.mode === 'fallback' ? 'Ready (tools-only)' : 'Ready', 'ok')
       }
     } catch (err) {
+      if (!stillThisRun()) return
       const msg = err?.message || String(err)
       if (/cancel|abort|stopped/i.test(msg)) {
         if (streamBody && !acc) {
@@ -1016,14 +1043,17 @@ export function createQvacView(opts) {
         } else if (streamBody && acc) {
           paintAssistant(streamBody, acc + '\n\n_(Stopped.)_', false)
         }
-        setStatus('Stopped', 'warn')
+        setStatus('Stopped — ready for a new message', 'warn')
       } else {
         if (streamBody) streamBody.innerHTML = formatMdLite(`Error: ${msg}`)
         setStatus(msg, 'error')
       }
     } finally {
-      setBusyUi(false)
+      // Only the active run owns the composer; Stop already unlocked via finishStoppedUi
-      syncModelChip()
+      if (stillThisRun()) {
+        setBusyUi(false)
+        syncModelChip()
+      }
     }
   }
 
@@ -1036,6 +1066,14 @@ export function createQvacView(opts) {
   }
 
   function newChat() {
+    // Cancel any in-flight turn and unlock composer
+    if (busy) {
+      engine.stop?.().catch(() => {})
+      finishStoppedUi()
+    } else {
+      engine.beginGeneration?.()
+      runId += 1
+    }
     releaseLiveSwarm()
     messages = []
     if (opts.els.messages) opts.els.messages.innerHTML = ''
@@ -1045,6 +1083,9 @@ export function createQvacView(opts) {
       'assistant',
       'New chat. Ask about host health, metrics, anomalies, or processes.'
     )
+    const mode = settings().qvacMode
+    setStatus(mode === 'qvac' ? 'Ready' : mode === 'fallback' ? 'Ready (tools-only)' : 'Ready', 'ok')
+    syncModelChip()
   }
 
   function resetOnboarding() {