diff --git a/desktop/src/workspace/local-workspace-agent-invocation.cjs b/desktop/src/workspace/local-workspace-agent-invocation.cjs
index acef3d6..51e5550 100644
--- a/desktop/src/workspace/local-workspace-agent-invocation.cjs
+++ b/desktop/src/workspace/local-workspace-agent-invocation.cjs
@@ -11,7 +11,6 @@ const {
   nextSessionMeta,
   normalizeOutcomeRefs,
   normalizeSessionMeta,
-  shouldRotateSession,
 } = require('../runs/run-harness.cjs')
 const {
   canonicalJson,
@@ -547,8 +546,13 @@ class LocalWorkspaceAgentInvocation {
     if (!taskId) throw new Error('LOCAL_RUN_TASK_INVALID')
     let workspacePath = group.workdir ? path.resolve(group.workdir) : group.id
     try { workspacePath = fs.realpathSync(workspacePath) } catch { /* runtime validates unavailable directories */ }
+    // Direct chats are independent execution surfaces. Scope their scheduler
+    // resource to the chat so one writable chat cannot block another Agent.
+    const schedulerWorkspaceKey = group.conversationType === 'direct'
+      ? `${workspacePath}\u0000direct:${group.id}`
+      : workspacePath
     const workspaceKey = createHash('sha256')
-      .update(String(workspacePath))
+      .update(String(schedulerWorkspaceKey))
       .digest('hex')
     const writerKind = cleanText(context.singleWriterKind || context.writerKind, 80)
     const permissionMode = group.allowWrite === true
@@ -719,10 +723,9 @@ class LocalWorkspaceAgentInvocation {
       && !resumedConnectorGate
       ? context.resumedGate
       : null
-    const preserveGroupSession = group.conversationType !== 'direct'
-    const sessionNeedsRotation = sessionRef
-      && shouldRotateSession(sessionMeta)
-      && !preserveGroupSession
+    // A conversation owns one native session for its lifetime. Rebuild only
+    // when the Agent reports that the existing native session is invalid.
+    const sessionNeedsRotation = false
     if (resumedPermission) {
       const requestHash = sha256(canonicalJson(resumedPermission.request))
       const persistedBinding = {
@@ -1269,6 +1272,8 @@ class LocalWorkspaceAgentInvocation {
           ].join('\n')
       const buildPrompt = (afterKind, contextPackage) => isolated || frozen
         ? v4Prompt
+        : group.conversationType === 'direct'
+          ? contextPackage.currentTaskText
         : [
             context.v4 === true && v4Prompt
               ? v4Prompt
diff --git a/desktop/src/workspace/local-workspace-conversations.cjs b/desktop/src/workspace/local-workspace-conversations.cjs
index b556f56..c68fd7c 100644
--- a/desktop/src/workspace/local-workspace-conversations.cjs
+++ b/desktop/src/workspace/local-workspace-conversations.cjs
@@ -23,6 +23,7 @@ class LocalWorkspaceConversations {
     this.isGroupBusy = options.isGroupBusy
     this.clearSessionState = options.clearSessionState
     this.runLedger = options.runLedger
+    this.discardAttachments = options.discardAttachments
     this.agentLabel = options.agentLabel
     this.createId = options.createId
     this.now = options.now
@@ -152,11 +153,17 @@ class LocalWorkspaceConversations {
     if (!state.groups.some(group => group.id === groupId)) {
       throw new Error('LOCAL_GROUP_NOT_FOUND')
     }
+    const attachmentIds = [...new Set(state.messages
+      .filter(message => message.groupId === groupId)
+      .flatMap(message => Array.isArray(message.attachments) ? message.attachments : [])
+      .map(attachment => attachment?.id)
+      .filter(id => typeof id === 'string'))]
     this.commit(() => {
       this.clearSessionState(groupId)
       state.groups = state.groups.filter(group => group.id !== groupId)
       state.messages = state.messages.filter(message => message.groupId !== groupId)
     }, () => this.runLedger?.deleteGroup?.(groupId))
+    this.discardAttachments?.(attachmentIds)
   }
 
   deleteMessage(groupId, messageId) {
diff --git a/desktop/src/workspace/local-workspace.cjs b/desktop/src/workspace/local-workspace.cjs
index 1c19070..616b3a0 100644
--- a/desktop/src/workspace/local-workspace.cjs
+++ b/desktop/src/workspace/local-workspace.cjs
@@ -217,6 +217,13 @@ class LocalWorkspace extends EventEmitter {
     })
     this.runLedgerCoordinator = new LocalWorkspaceRunLedger({
       runLedger: this.runLedger,
+      discardAttachments: ids => {
+        const referenced = new Set(this.state.messages.flatMap(message => (
+          Array.isArray(message.attachments) ? message.attachments : []
+        )).map(attachment => attachment?.id).filter(Boolean))
+        const orphaned = ids.filter(id => !referenced.has(id))
+        if (orphaned.length) this.contentBlobStore.discard(orphaned)
+      },
       state: () => this.state,
       save: () => this.save(),
       createId: () => this.createId(),
diff --git a/desktop/test/workspace/local-workspace-native-streaming.test.cjs b/desktop/test/workspace/local-workspace-native-streaming.test.cjs
index ade1971..f180ddb 100644
--- a/desktop/test/workspace/local-workspace-native-streaming.test.cjs
+++ b/desktop/test/workspace/local-workspace-native-streaming.test.cjs
@@ -66,6 +66,32 @@ test('direct Pi conversations reuse the native JSON session across messages', as
   assert.deepEqual(calls.map(call => call.runOptions.sessionTransport), ['', ''])
 })
 
+test('direct conversations do not rotate their session after the default turn budget', async (t) => {
+  const { directory, calls, options } = fixture()
+  t.after(() => fs.rmSync(directory, { recursive: true, force: true }))
+  options.detectAgents = async () => [{
+    kind: 'pi', name: 'Pi Agent', executable: '/tmp/pi', version: '0.84.2',
+  }]
+  options.runAgent = async (_agent, prompt, _workdir, runOptions) => {
+    calls.push({ prompt, runOptions })
+    const sessionRef = runOptions.sessionRef || 'pi-long-session'
+    await runOptions.onSessionRef(sessionRef)
+    return { text: 'reply', sessionRef, outcome: 'completed' }
+  }
+  const workspace = new LocalWorkspace(options)
+  await workspace.refreshAgents()
+  const group = workspace.createGroup({
+    name: 'Long direct', agentKinds: ['pi'], directAgentKind: 'pi',
+    conversationType: 'direct', workdir: directory,
+  })
+  for (let index = 0; index < 20; index += 1) {
+    await workspace.sendMessage({ groupId: group.id, text: `message-${index}` })
+  }
+  assert.equal(calls.length, 20)
+  assert.equal(calls.filter(call => call.runOptions.sessionRef === '').length, 1)
+  assert.equal(calls.slice(1).every(call => call.runOptions.sessionRef === 'pi-long-session'), true)
+})
+
 test('group conversations dispatch Pi alongside other available Agents', async (t) => {
   const { directory, calls, options } = fixture()
   t.after(() => fs.rmSync(directory, { recursive: true, force: true }))
diff --git a/desktop/test/workspace/local-workspace-write-scheduling.test.cjs b/desktop/test/workspace/local-workspace-write-scheduling.test.cjs
index a7bd4c7..fa8eaa3 100644
--- a/desktop/test/workspace/local-workspace-write-scheduling.test.cjs
+++ b/desktop/test/workspace/local-workspace-write-scheduling.test.cjs
@@ -82,6 +82,35 @@ test('read-only group invocations retain parallel execution in the same director
   await Promise.all(runs)
 })
 
+test('writable direct chats do not block another Agent in the same directory', { timeout: 10000 }, async (t) => {
+  const { directory, options } = fixture()
+  const release = deferred()
+  const bothStarted = deferred()
+  t.after(() => {
+    release.resolve()
+    fs.rmSync(directory, { recursive: true, force: true })
+  })
+  options.runScheduler = new RunScheduler()
+  const calls = []
+  options.runAgent = async (agent, _prompt, _cwd, runOptions) => {
+    calls.push({ kind: agent.kind, sandbox: runOptions.sandbox })
+    if (calls.length === 2) bothStarted.resolve()
+    await release.promise
+    return { text: `${agent.kind} completed.` }
+  }
+  const workspace = new LocalWorkspace(options)
+  await workspace.refreshAgents()
+  const groups = ['codex', 'hermes'].map(kind => workspace.createGroup({
+    name: `${kind} direct`, agentKinds: [kind], directAgentKind: kind,
+    conversationType: 'direct', workdir: directory, allowWrite: true,
+  }))
+  const runs = groups.map(group => workspace.sendMessage({ groupId: group.id, text: 'Run independently.' }))
+  await bothStarted.promise
+  assert.deepEqual(calls.map(call => call.sandbox), ['workspace-write', 'workspace-write'])
+  release.resolve()
+  await Promise.all(runs)
+})
+
 test('Manual V4 retains parallel readers alongside its single writer and stable message order', { timeout: 10000 }, async (t) => {
   const { directory, options } = fixture()
   const release = deferred()
diff --git a/desktop/test/workspace/local-workspace.test.cjs b/desktop/test/workspace/local-workspace.test.cjs
index a8da1f9..33a7161 100644
--- a/desktop/test/workspace/local-workspace.test.cjs
+++ b/desktop/test/workspace/local-workspace.test.cjs
@@ -1399,6 +1399,7 @@ test('direct conversations force manual mode and reuse their group Agent session
   assert.equal(direct.directAgentKind, 'codex')
   assert.deepEqual(calls.map(call => call.agent.kind), ['codex', 'codex'])
   assert.deepEqual(calls.map(call => call.runOptions.sessionRef), ['', 'codex-session'])
+  assert.deepEqual(calls.map(call => call.prompt), ['第一条', '第二条'])
   assert.equal(calls.some(call => call.prompt.includes('MELDWORK_CONSENSUS')), false)
   assert.equal(workspace.snapshot().messages.some(message => message.threadRootId), false)
   const restored = new LocalWorkspace(options)