refactor(desktop): dedupe the live-turn reconciler seams

- `reconcilePersistedLiveTurn` called `reconcileAuthoritativeChatMessages`
  back through a callback that was the caller itself; the projection-less
  branch is now `reconcileDurableHistory` in utils and imported directly.
- The activation path retried the live-turn reconcile inside its fallback
  with the same rows; `null` does not depend on `previous`, so the retry was
  dead work. The fallback now runs the durable path only.
- `isLiveTailReplyId` (spoken-reply) replaces the third and fourth copies of
  the `assistant-stream-`/`inflight-assistant-` prefix predicate; `normalizeWs`
  is exported from chat-messages instead of re-declared in coverage.ts and
  the journal; `isCommittedRow` names the "not a projection, not a recovery"
  predicate the journal repeated three times.
- Loop-invariant `lastPreviousUser` hoisted; `renderedText(raw)` computed once
  per row instead of per part; `snapshotIntervals` skips the code-point split
  when there are no corrections; `persistInFlightTurnState` checks for a
  recovered row before building the recoverable tail on every idle commit.

apps/desktop/src/app/session/hooks/use-session-actions/index.ts

@@ -166,7 +166,7 @@ import {
   patchSessionWorkspace,
   preserveEquivalentTranscript,
   preserveLocalPendingTurnMessages,
-  reconcileResumeMessages,
+  reconcileDurableHistory,
   removeRepresentedLocalLiveProjection,
   resolveResumedBusy,
   resolveSessionProfile,
@@ -266,27 +266,17 @@ function reconcileAuthoritativeChatMessages(
   sourceRows?: SessionMessage[]
 ): ChatMessage[] {
   if (liveProjection && sourceRows) {
-    const reconciled = reconcilePersistedLiveTurn(
-      authoritativeMessages,
-      previousMessages,
-      sourceRows,
-      liveProjection,
-      (messages, previous) => reconcileAuthoritativeChatMessages(messages, previous)
-    )
+    const reconciled = reconcilePersistedLiveTurn(authoritativeMessages, previousMessages, sourceRows, liveProjection)
 
     if (reconciled) {
       return reconciled
     }
   }
 
-  const withLiveProjection = liveProjection
-    ? appendLiveSessionProjection(authoritativeMessages, liveProjection)
-    : authoritativeMessages
-
-  const reconciled = reconcileResumeMessages(withLiveProjection, previousMessages)
-  const withPendingTurn = preserveLocalPendingTurnMessages(reconciled, previousMessages)
-
-  return preserveLocalAssistantErrors(withPendingTurn, previousMessages)
+  return reconcileDurableHistory(
+    liveProjection ? appendLiveSessionProjection(authoritativeMessages, liveProjection) : authoritativeMessages,
+    previousMessages
+  )
 }
 
 function reconcileAuthoritativeMessages(
@@ -1528,19 +1518,14 @@ export function useSessionActions({
                     persistedMessages,
                     sessionStateByRuntimeIdRef.current.get(cachedRuntimeId)?.messages ?? previousMessages,
                     persisted.messages,
-                    liveProjection,
-                    (messages, previous) => reconcileAuthoritativeChatMessages(messages, previous)
+                    liveProjection
                   )
 
+                  // `null` does not depend on `previous`; retrying the live-turn
+                  // reconcile inside the fallback would return `null` again.
                   reconciledCurrentLiveTurn = currentLiveTurn !== null
                   activatedMessages =
-                    currentLiveTurn ??
-                    reconcileAuthoritativeChatMessages(
-                      persistedMessages,
-                      previousMessages,
-                      liveProjection,
-                      persisted.messages
-                    )
+                    currentLiveTurn ?? reconcileAuthoritativeChatMessages(persistedMessages, previousMessages, liveProjection)
                 }
               }
 

apps/desktop/src/app/session/hooks/use-session-actions/live-turn-remainder.test.ts

@@ -113,7 +113,7 @@ it('pairs only the queue projection, preserving equal corrections and different
   }
 
   const reconcile = (previous: ChatMessage[]) =>
-    reconcilePersistedLiveTurn(toChatMessages(rows), previous, rows, projection, messages => messages)!
+    reconcilePersistedLiveTurn(toChatMessages(rows), previous, rows, projection)!
 
   let current = reconcile([])
 

apps/desktop/src/app/session/hooks/use-session-actions/persisted-live-turn.ts

@@ -5,6 +5,7 @@ import { parseErrorSurface } from '@/lib/error-surface'
 import type { SessionMessage, SessionResumeResult } from '@/types/hermes'
 
 import { mergeLiveAssistantRun } from './live-turn-remainder'
+import { reconcileDurableHistory } from './utils'
 
 const rowId = (row: SessionMessage) => row.row_id ?? row.id
 const userText = (text: string) => textWithoutReferenceLines(text).trim()
@@ -68,12 +69,12 @@ function candidateTurn(
 
       // MEDIA rendering and folding change lengths. Only source-row provenance,
       // not equal prose elsewhere in the transcript, proves display coverage.
+      const rendered = renderedText(raw).trim()
+
       if (
         id === undefined ||
         !turnMessages.some(message =>
-          message.parts.some(
-            part => part.type === 'text' && part.sourceRowId === id && part.text.trim() === renderedText(raw).trim()
-          )
+          message.parts.some(part => part.type === 'text' && part.sourceRowId === id && part.text.trim() === rendered)
         )
       ) {
         return null
@@ -162,6 +163,11 @@ function snapshotIntervals(inflight: NonNullable<SessionResumeResult['inflight']
   const text = inflight.assistant ?? ''
   const corrections = inflight.corrections ?? []
   const offsets = inflight.correction_offsets
+
+  if (!corrections.length) {
+    return [text]
+  }
+
   // Python's len() counts Unicode code points, unlike JS string offsets.
   const characters = Array.from(text)
 
@@ -192,8 +198,7 @@ export function reconcilePersistedLiveTurn(
   messages: ChatMessage[],
   previous: ChatMessage[],
   rows: SessionMessage[],
-  projection: Pick<SessionResumeResult, 'inflight' | 'queued' | 'session_id'>,
-  reconcileHistory: (messages: ChatMessage[], previous: ChatMessage[]) => ChatMessage[]
+  projection: Pick<SessionResumeResult, 'inflight' | 'queued' | 'session_id'>
 ): ChatMessage[] | null {
   const inflight = projection.inflight
 
@@ -233,7 +238,7 @@ export function reconcilePersistedLiveTurn(
   const snapshots = snapshotIntervals(inflight)
   const corrections = inflight.corrections ?? []
 
-  const result = reconcileHistory(
+  const result = reconcileDurableHistory(
     messages.slice(0, turn.start + 1),
     localStart >= 0 ? previous.slice(0, localStart + 1) : previous
   )

apps/desktop/src/app/session/hooks/use-session-actions/utils.ts

@@ -1,11 +1,19 @@
 import { resolveSessionRpcOwner } from '@/app/contrib/wiring-routing'
 import { textWithoutReferenceLines } from '@/components/assistant-ui/reference-kinds'
 import { getSession } from '@/hermes'
-import { assistantTextPart, type ChatMessage, chatMessageText, textPart, toChatMessages } from '@/lib/chat-messages'
+import {
+  assistantTextPart,
+  type ChatMessage,
+  chatMessageText,
+  preserveLocalAssistantErrors,
+  textPart,
+  toChatMessages
+} from '@/lib/chat-messages'
 import { normalizePersonalityValue } from '@/lib/chat-runtime'
 import { embeddedImageUrls, textWithoutEmbeddedImages } from '@/lib/embedded-images'
 import { parseErrorSurface } from '@/lib/error-surface'
 import { isMessagingSource, normalizeSessionSource } from '@/lib/session-source'
+import { isLiveTailReplyId } from '@/lib/spoken-reply'
 import { reconcileApprovalModeForProfile } from '@/store/approval-mode'
 import { requestDesktopOnboardingForCredentialWarning } from '@/store/onboarding'
 import { $activeGatewayProfile, $profiles, normalizeProfileKey } from '@/store/profile'
@@ -78,12 +86,7 @@ function hasStructuralParts(message: ChatMessage): boolean {
  * turn — as opposed to a committed transcript row.
  */
 function isLiveTailRow(message: ChatMessage): boolean {
-  return (
-    message.pending === true ||
-    message.id.startsWith('assistant-stream-') ||
-    message.id.startsWith('inflight-assistant-') ||
-    message.interim === true
-  )
+  return message.pending === true || isLiveTailReplyId(message.id) || message.interim === true
 }
 
 /**
@@ -334,6 +337,15 @@ export function preserveEquivalentTranscript(current: ChatMessage[], next: ChatM
   return chatMessageArraysEquivalent(current, next) ? current : next
 }
 
+/** Durable history against the local view: role-ordinal pairing, then the
+ *  local pending turn and local assistant errors the DB cannot know about. */
+export function reconcileDurableHistory(messages: ChatMessage[], previous: ChatMessage[]): ChatMessage[] {
+  const reconciled = reconcileResumeMessages(messages, previous)
+  const withPendingTurn = preserveLocalPendingTurnMessages(reconciled, previous)
+
+  return preserveLocalAssistantErrors(withPendingTurn, previous)
+}
+
 export function reconcileResumeMessages(nextMessages: ChatMessage[], previousMessages: ChatMessage[]): ChatMessage[] {
   if (!previousMessages.length) {
     return nextMessages
@@ -580,8 +592,7 @@ function durableFoldCoversLiveResponse(messages: ChatMessage[], live: ChatMessag
   return messages.slice(lastUser + 1).some(message => {
     if (
       message.role !== 'assistant' ||
-      message.id.startsWith('assistant-stream-') ||
-      message.id.startsWith('inflight-assistant-')
+      isLiveTailReplyId(message.id)
     ) {
       return false
     }
@@ -655,6 +666,7 @@ export function preserveLocalPendingTurnMessages(
   // Authoritative id → richer local pending row. Replacing (not appending)
   // avoids painting both the empty inflight shell and the full stream bubble.
   const replacements = new Map<string, ChatMessage>()
+  const lastPreviousUser = previousMessages.findLastIndex(row => row.role === 'user' && !isGatewaySystemMarker(row))
 
   for (const message of previousMessages) {
     if (isGatewaySystemMarker(message)) {
@@ -794,8 +806,6 @@ export function preserveLocalPendingTurnMessages(
       }
     }
 
-    const lastPreviousUser = previousMessages.findLastIndex(row => row.role === 'user' && !isGatewaySystemMarker(row))
-
     if (
       isPendingAssistant &&
       previousMessages.indexOf(message) > lastPreviousUser &&

apps/desktop/src/lib/chat-messages/coverage.ts

@@ -1,7 +1,6 @@
+import { normalizeWs as normalizedText } from './parts'
 import type { ChatMessage, ChatMessagePart } from './types'
 
-const normalizedText = (value: string) => value.replace(/\s+/g, ' ').trim()
-
 function sameOccurrencePart(stored: ChatMessagePart, local: ChatMessagePart): boolean {
   if (stored.type === 'tool-call' && local.type === 'tool-call') {
     return Boolean(stored.toolCallId) && stored.toolCallId === local.toolCallId

apps/desktop/src/lib/chat-messages/index.ts

@@ -8,6 +8,7 @@ export {
   completeOpenTimelineParts,
   dedupeRepeatedTextInParts,
   mergeFinalAssistantText,
+  normalizeWs,
   reasoningPart,
   renderMediaTags,
   textPart

apps/desktop/src/lib/inflight-turn-journal.ts

@@ -1,5 +1,11 @@
-import { type ChatMessage, type ChatMessagePart, chatMessageText } from '@/lib/chat-messages'
+import {
+  type ChatMessage,
+  type ChatMessagePart,
+  chatMessageText,
+  normalizeWs as normalizedText
+} from '@/lib/chat-messages'
 import { withoutCoveredAssistantPrefix } from '@/lib/chat-messages/coverage'
+import { isLiveTailReplyId } from '@/lib/spoken-reply'
 
 /**
  * Crash-survivable in-flight turn journal.
@@ -523,10 +529,6 @@ function cloneMessages(messages: ChatMessage[]): ChatMessage[] {
   }
 }
 
-function normalizedText(value: string): string {
-  return value.replace(/\s+/g, ' ').trim()
-}
-
 function attachmentSignature(message: ChatMessage): string {
   return (message.attachmentRefs ?? []).join('\n')
 }
@@ -556,11 +558,13 @@ function assistantHasRecoverableContent(message: ChatMessage): boolean {
 /** A live-turn projection row (backend `inflight` via appendLiveSessionProjection,
  *  or a still-streaming local bubble) — as opposed to a completed transcript row. */
 function isLiveProjectionRow(message: ChatMessage): boolean {
-  return (
-    Boolean(message.pending) ||
-    message.id.startsWith('assistant-stream-') ||
-    message.id.startsWith('inflight-assistant-')
-  )
+  return Boolean(message.pending) || isLiveTailReplyId(message.id)
+}
+
+/** A row the transcript actually holds: neither a live projection nor a
+ *  journal recovery that is still waiting for its durable counterpart. */
+function isCommittedRow(message: ChatMessage): boolean {
+  return !isLiveProjectionRow(message) && !message.recovered
 }
 
 /** Visible tail of the running turn: the streaming assistant row (plus any
@@ -716,7 +720,7 @@ function journalTailAlreadyCommitted(tailAssistants: ChatMessage[], baseMessages
   const lastTurnStart = baseMessages.findLastIndex(message => message.role === 'user' && !message.hidden)
 
   return recoverable.every(message => baseMessages.some((base, index) =>
-    base.role === 'assistant' && !base.hidden && !isLiveProjectionRow(base) && !base.recovered &&
+    base.role === 'assistant' && !base.hidden && isCommittedRow(base) &&
     (base.id === message.id ||
       (message.rowId === undefined ? index > lastTurnStart : base.rowId !== undefined && base.rowId === message.rowId)) &&
     base.error === message.error &&
@@ -806,7 +810,7 @@ export function mergeInFlightMessages(
   const afterUser = baseMessages.slice(matchingUserIndex + 1, end)
 
   const completedReply = afterUser.find(
-    message => assistantHasRecoverableContent(message) && !isLiveProjectionRow(message) && !message.recovered &&
+    message => assistantHasRecoverableContent(message) && isCommittedRow(message) &&
       (message.durableComplete === true || (message.durableComplete === undefined && !message.interim &&
         !message.parts.some(part => part.type === 'tool-call')))
   )
@@ -817,7 +821,7 @@ export function mergeInFlightMessages(
   }
 
   tailAssistants = withoutCoveredAssistantPrefix(
-    afterUser.filter(message => !isLiveProjectionRow(message) && !message.recovered), tailAssistants
+    afterUser.filter(isCommittedRow), tailAssistants
   )
   lastJournalRow = tailAssistants.findLast(assistantHasRecoverableContent) ?? null
 
@@ -961,7 +965,8 @@ export function persistInFlightTurnState(state: JournalableSessionState): void {
   }
 
   if (!state.busy && !state.awaitingResponse && !state.streamId &&
-      !recoverableTail(state.messages, null).some(message => message.recovered)) {
+      !(state.messages.some(message => message.recovered) &&
+        recoverableTail(state.messages, null).some(message => message.recovered))) {
     clearInFlightTurnJournal(storedSessionId)
 
     return