diff --git a/packages/client/runtime/src/client/sessions/conversation-assembler.ts b/packages/client/runtime/src/client/sessions/conversation-assembler.ts
index 3b6fbd6266..3a0c94ba3c 100644
--- a/packages/client/runtime/src/client/sessions/conversation-assembler.ts
+++ b/packages/client/runtime/src/client/sessions/conversation-assembler.ts
@@ -238,7 +238,7 @@ export class ConversationNodeAssembler {
     }
     this.applyPendingMatches(pending, affected)
     this.replayContexts(affected)
-    if ((fresh.length > 0 || previousHasMore !== hasMore) && this.replayDependencies()) {
+    if ((this.revised.size > 0 || previousHasMore !== hasMore) && this.replayDependencies()) {
       publication = 'immediate'
     }
     if (changedLocations.size > 0) publication = 'immediate'
@@ -563,18 +563,18 @@ export class ConversationNodeAssembler {
 
   private replayRevisedDependents(): boolean {
     const pending = [...this.revised]
-    const replayed = new Set<InternalContext>()
+    const affected = new Set<InternalContext>()
     for (let index = 0; index < pending.length; index++) {
       const dependency = pending[index]
       if (dependency === undefined) continue
       for (const dependent of this.dependents.get(dependency.key) ?? []) {
-        if (replayed.has(dependent)) continue
-        replayed.add(dependent)
-        this.replayContext(dependent)
+        if (affected.has(dependent)) continue
+        affected.add(dependent)
         pending.push(dependent)
       }
     }
-    return replayed.size > 0
+    this.replayContexts(affected)
+    return affected.size > 0
   }
 
   private readerFor(
diff --git a/packages/client/runtime/src/client/sessions/session.ts b/packages/client/runtime/src/client/sessions/session.ts
index a533f9dd6f..7c3d989248 100644
--- a/packages/client/runtime/src/client/sessions/session.ts
+++ b/packages/client/runtime/src/client/sessions/session.ts
@@ -344,6 +344,7 @@ export class Session implements SessionFace {
         // §D.2 continuity assertion: on violation drop the page fail-soft rather than render an out-of-order stream.
         console.error(`[web-runtime] history page discontinuous: tail seq ${tail?.event.seq} vs baseSeq ${this.baseSeq}`)
         this.hasMore = false
+        this.conversation.prepend([], false)
         return
       }
       this.events = [...older.map(e => e.event), ...this.events]
diff --git a/packages/client/runtime/tests/conversation-assembler.spec.ts b/packages/client/runtime/tests/conversation-assembler.spec.ts
index 6f4d8516dc..06dfd42567 100644
--- a/packages/client/runtime/tests/conversation-assembler.spec.ts
+++ b/packages/client/runtime/tests/conversation-assembler.spec.ts
@@ -458,6 +458,73 @@ describe('ConversationNodeAssembler', () => {
     expect([...chatSnapshot(assembler)?.nodes.values() ?? []][0]?.data).toBe(2)
   })
 
+  it('replays a transitive dependency closure in start order', () => {
+    const sourceA: ConversationNodeDefinition<number> = {
+      kind: 'diamond-a',
+      match: (event) => {
+        if (event.type === 'user/message') return { id: 'one', role: 'start' }
+        if ((event.type as string) === 'diamond/a') return { id: 'one', role: 'update' }
+        return null
+      },
+      start: () => 1,
+      update: (_context, match) => (match.event.data as unknown as { value: number }).value,
+      buildViewNode: () => null,
+    }
+    const sourceX: ConversationNodeDefinition<number> = {
+      kind: 'diamond-x',
+      match: (event) => {
+        if (event.type === 'turn/start') return { id: 'one', role: 'start' }
+        if ((event.type as string) === 'diamond/x') return { id: 'one', role: 'update' }
+        return null
+      },
+      start: () => 10,
+      update: (_context, match) => (match.event.data as unknown as { value: number }).value,
+      buildViewNode: () => null,
+    }
+    const middle: ConversationNodeDefinition<number> = {
+      kind: 'diamond-b',
+      match: event => event.type === 'assistant/message'
+        ? { id: 'one', role: 'start' }
+        : null,
+      start: (_context, _match, reader) => (
+        (reader.previous<number>('diamond-a')?.state ?? 0)
+        + (reader.previous<number>('diamond-x')?.state ?? 0)
+      ),
+      update: context => context.state,
+      buildViewNode: context => node(context, context.state),
+    }
+    const consumer: ConversationNodeDefinition<number> = {
+      kind: 'diamond-c',
+      match: event => event.type === 'tool/call'
+        ? { id: 'one', role: 'start' }
+        : null,
+      start: (_context, _match, reader) => (
+        (reader.previous<number>('diamond-a')?.state ?? 0) * 100
+        + (reader.previous<number>('diamond-b')?.state ?? 0)
+      ),
+      update: context => context.state,
+      buildViewNode: context => node(context, context.state),
+    }
+    const assembler = new ConversationNodeAssembler(
+      new TestEventDefinitions([sourceA, sourceX, middle, consumer]),
+      new TestViewDefinitions([testView()]),
+    )
+    assembler.replaceWindow([
+      input(at(1, 'user/message', { id: 'source', content: [], source: { kind: 'user' } })),
+      input(at(2, 'turn/start', { turn: 1 })),
+      input(at(3, 'assistant/message', { turn: 1, step: 1, message: { role: 'assistant', content: [] } })),
+      input(at(4, 'tool/call', { turn: 1, step: 1, callId: 'call', name: 'x', arguments: '{}' })),
+    ], false)
+
+    assembler.append(input(at(5, 'diamond/x', { value: 20 })))
+    assembler.append(input(at(6, 'diamond/a', { value: 2 })))
+    assembler.flush()
+
+    const value = [...chatSnapshot(assembler)?.nodes.values() ?? []]
+      .find(candidate => candidate.kind === 'diamond-c')
+    expect(value?.data).toBe(222)
+  })
+
   it('replays Location-derived State and rebuilds only owned Nodes when a step closes', () => {
     const apply = vi.fn()
     const starts = vi.fn((
diff --git a/packages/client/ui-conversation/src/client/conversation-nodes/turn-tail.ts b/packages/client/ui-conversation/src/client/conversation-nodes/turn-tail.ts
index 2a842a005d..346bd41bdf 100644
--- a/packages/client/ui-conversation/src/client/conversation-nodes/turn-tail.ts
+++ b/packages/client/ui-conversation/src/client/conversation-nodes/turn-tail.ts
@@ -122,14 +122,26 @@ function tailData(context: ConversationNodeContext<TurnTailState>): TurnTailChat
     .filter((candidate): candidate is Readonly<FinalAssistantChatData> => candidate.finalNode !== undefined)
     .sort((left, right) => left.finalNode.seq - right.finalNode.seq)
   const closing = finalized.findLast(hasText) ?? null
-  const latest = finalized.at(-1)
+  let latestTranscriptSeq = finalized.at(-1)?.finalNode.seq
+  for (const match of context.matches) {
+    const event = match.event
+    const candidate = event.type === 'tool/call'
+      || (event.type === 'tool/result' && isAppendSurfaceEvent(event))
+      || (event.type === 'turn/end' && event.data.reason.kind === 'error')
+      || (event.type as string) === 'llm/retry'
+      ? event.seq
+      : undefined
+    if (candidate !== undefined && (latestTranscriptSeq === undefined || candidate > latestTranscriptSeq)) {
+      latestTranscriptSeq = candidate
+    }
+  }
   const metrics = deriveTurnMetrics(finalized.map(candidate => candidate.finalNode)).get(end.event.data.turn)
   return {
     turn: end.event.data.turn,
     seq: end.event.seq,
     time: end.event.time,
     closing,
-    branchUnavailable: closing === null || latest?.finalNode.seq !== closing.finalNode.seq,
+    branchUnavailable: closing === null || latestTranscriptSeq !== closing.finalNode.seq,
     ...metrics?.ttftMs === undefined ? {} : { ttftMs: metrics.ttftMs },
     ...metrics?.tokensPerSecond === undefined ? {} : { tokensPerSecond: metrics.tokensPerSecond },
   }
@@ -141,6 +153,9 @@ export const turnTailDefinition: ConversationNodeDefinition<TurnTailState> = {
   match: (event) => {
     if (event.type === 'turn/start') return { id: String(event.data.turn), role: 'start' }
     if (event.type === 'turn/end') return { id: String(event.data.turn), role: 'update' }
+    if (event.type === 'tool/call' || event.type === 'tool/result') {
+      return { id: String(event.data.turn), role: 'update' }
+    }
     const coordinates = turnCoordinates(event)
     if (coordinates !== undefined) return { id: String(coordinates.turn), role: 'update' }
     return null
diff --git a/packages/client/ui-conversation/src/client/index.ts b/packages/client/ui-conversation/src/client/index.ts
index b4d7467170..e0471623f0 100644
--- a/packages/client/ui-conversation/src/client/index.ts
+++ b/packages/client/ui-conversation/src/client/index.ts
@@ -3,19 +3,18 @@
  * between the independently implemented skeleton and chat domains; `apply.ts`
  * owns their slot assembly.
  */
+export type {} from './conversation-nodes/assistant.ts'
+export type {} from './conversation-nodes/command.ts'
+export type {} from './conversation-nodes/compaction.ts'
+export type {} from './conversation-nodes/fallback.ts'
+export type {} from './conversation-nodes/message.ts'
+export type {} from './conversation-nodes/retry.ts'
+export type {} from './conversation-nodes/tool.ts'
+export type {} from './conversation-nodes/turn-error.ts'
+export type {} from './conversation-nodes/turn-tail.ts'
+
 export { apply, inject } from './apply.ts'
 export { ConversationService } from './service.ts'
-export { registerAssistantConversationNode } from './conversation-nodes/assistant.ts'
-export { registerChatConversationView } from './conversation-nodes/chat-snapshot-builder.ts'
-export { registerCommandConversationNode } from './conversation-nodes/command.ts'
-export { registerCompactionConversationNode } from './conversation-nodes/compaction.ts'
-export { registerUnknownConversationFallback } from './conversation-nodes/fallback.ts'
-export { registerInboxConversationNodes } from './conversation-nodes/inbox.ts'
-export { registerMessageConversationNode } from './conversation-nodes/message.ts'
-export { registerRetryConversationNode } from './conversation-nodes/retry.ts'
-export { registerToolConversationNode } from './conversation-nodes/tool.ts'
-export { registerTurnErrorConversationNode } from './conversation-nodes/turn-error.ts'
-export { registerTurnTailConversationNode } from './conversation-nodes/turn-tail.ts'
 export type { IConversation } from './service.ts'
 
 export type {
diff --git a/packages/client/ui-conversation/tests/conversation-node-definitions.spec.ts b/packages/client/ui-conversation/tests/conversation-node-definitions.spec.ts
index 3ae906087e..5346ad57f9 100644
--- a/packages/client/ui-conversation/tests/conversation-node-definitions.spec.ts
+++ b/packages/client/ui-conversation/tests/conversation-node-definitions.spec.ts
@@ -16,7 +16,7 @@ import { toolDefinition } from '../src/client/conversation-nodes/tool.ts'
 import { turnErrorDefinition } from '../src/client/conversation-nodes/turn-error.ts'
 import { turnTailDefinition } from '../src/client/conversation-nodes/turn-tail.ts'
 import type {
-  AssistantChatData, ManualCompactionChatData, RetryChatData, ToolChatData,
+  AssistantChatData, ManualCompactionChatData, RetryChatData, ToolChatData, TurnTailChatData,
 } from '../src/client/contract/chat-nodes.ts'
 
 const DEFINITIONS: readonly ConversationNodeDefinition[] = [
@@ -413,6 +413,30 @@ describe('built-in conversation node Definitions', () => {
     ])
   })
 
+  it('keeps branching unavailable when a tool result follows the closing Assistant', () => {
+    const value = assembler([
+      at(1, 'turn/start', { turn: 1 }),
+      at(2, 'step/start', { turn: 1, step: 1 }),
+      at(3, 'assistant/message', {
+        turn: 1,
+        step: 1,
+        message: assistantMessage('assistant-before-tool', 'running a tool'),
+      }, { surfaceOp: 'append' }),
+      at(4, 'tool/call', { turn: 1, step: 1, callId: 'late-tool', name: 'read', arguments: '{}' }),
+      at(5, 'tool/result', {
+        turn: 1,
+        step: 1,
+        message: toolResult('late-tool', 'done'),
+      }, { surfaceOp: 'append' }),
+      at(6, 'step/end', { turn: 1, step: 1 }),
+      at(7, 'turn/end', { turn: 1, reason: { kind: 'completed' } }),
+    ])
+
+    const tail = node(snapshot(value), 'turn-tail')?.data as TurnTailChatData
+    expect(tail.closing?.finalNode.seq).toBe(3)
+    expect(tail.branchUnavailable).toBe(true)
+  })
+
   it('replays inbox predecessors after prepend and reclassifies the dependent message as steering', () => {
     const value = assembler([
       at(3, 'user/message', textMessage('steer-1', 'change direction'), { surfaceOp: 'append' }),
diff --git a/scripts/gen-cordis-catalog.ts b/scripts/gen-cordis-catalog.ts
index 51fdc06f61..662ad1df13 100644
--- a/scripts/gen-cordis-catalog.ts
+++ b/scripts/gen-cordis-catalog.ts
@@ -121,6 +121,8 @@ export const SERVICE_WALK_EXEMPTIONS: Record<string, string> = {
   chatFileMentions: 'client-side slot-contract accessor (ChatFileMentions) — packages/client/ui-conversation/README.md owns the surface',
   command: 'client-side interface-typed browser service — packages/client/ui-command/README.md owns the surface',
   conversation: 'client-side interface-typed browser service — packages/client/ui-conversation/README.md owns the surface',
+  conversationEvents: 'client-side interface-typed registry — packages/client/runtime/README.md owns the surface',
+  conversationViews: 'client-side interface-typed registry — packages/client/runtime/README.md owns the surface',
   layout: 'client-side interface-typed browser service — packages/client/ui-layout/README.md owns the surface',
   locale: 'client-side interface-typed browser service — packages/client/locale/README.md owns the surface',
   models: 'client-side interface-typed browser service — packages/client/ui-model/README.md owns the surface',