diff --git a/lib/delivery.js b/lib/delivery.js
index 5caff5c..cd85de2 100644
--- a/lib/delivery.js
+++ b/lib/delivery.js
@@ -149,9 +149,7 @@ export function matchTargetForPeer(targets, peer) {
     const jid = String(route.jid || route.chatId || route.openId || route.userId || '').trim().toLowerCase()
     if (!jid) continue
     if (wantGroup && !jid.endsWith('@g.us')) continue
-    if (candidates.some((peerJid) => (
-      jid === peerJid || peerJid.endsWith(jid) || jid.endsWith(peerJid)
-    ))) {
+    if (candidates.some((peerJid) => jid === peerJid)) {
       return target
     }
   }
@@ -365,25 +363,64 @@ export async function resolveCreateDelivery(args = {}, exec = {}, deps = {}) {
   const targetId = typeof args.im_target_id === 'string' ? args.im_target_id.trim()
     : (typeof args.imTargetId === 'string' ? args.imTargetId.trim() : '')
 
+  const dshIm = deps.dshIm
+  const peer = await resolveCallerPeer(exec, dshIm)
+
+  // IM peers cannot retarget to an arbitrary catalog entry (confused deputy).
+  if (peer?.botId) {
+    if (explicit === 'dsh') return normalizeDelivery({ kind: 'dsh' })
+    const ensured = await ensureImDeliveryForPeer(peer, dshIm)
+    if (ensured) return ensured
+    if (explicit === 'im' || (botId && targetId)) {
+      const error = new Error('IM sessions cannot pick a free im_bot_id/im_target_id; delivery is bound to this chat')
+      error.code = 'IM_TARGET_FORBIDDEN'
+      throw error
+    }
+    return normalizeDelivery({ kind: 'dsh' })
+  }
+
   if (explicit === 'dsh') return normalizeDelivery({ kind: 'dsh' })
   if (explicit === 'im' || (botId && targetId)) {
     return normalizeDelivery({ kind: 'im', botId, targetId })
   }
 
-  const dshIm = deps.dshIm
-  const sessionId = callerSessionId(exec)
-  if (sessionId && dshIm && typeof dshIm.resolveSessionPeer === 'function') {
-    try {
-      const peer = await dshIm.resolveSessionPeer(sessionId)
-      const ensured = await ensureImDeliveryForPeer(peer, dshIm)
-      if (ensured) return ensured
-    } catch {
-      // fall through to dsh
-    }
-  }
   return normalizeDelivery({ kind: 'dsh' })
 }
 
+/**
+ * Resolve the IM peer for the tool-calling session, if any.
+ * @param {object} exec
+ * @param {object|undefined} dshIm
+ */
+export async function resolveCallerPeer(exec, dshIm) {
+  const sessionId = callerSessionId(exec)
+  if (!sessionId || !dshIm || typeof dshIm.resolveSessionPeer !== 'function') return null
+  try {
+    const peer = await dshIm.resolveSessionPeer(sessionId)
+    return peer?.botId ? peer : null
+  } catch {
+    return null
+  }
+}
+
+/**
+ * Whether a scheduled job was created from this IM conversation.
+ * Web/sidebar callers are unrestricted; IM peers only manage their own jobs.
+ * @param {object|null|undefined} job
+ * @param {object} peer
+ */
+export function jobVisibleToPeer(job, peer) {
+  if (!job || !peer?.botId) return false
+  const botId = String(peer.botId).trim()
+  const conversationKey = String(peer.conversationKey || '').trim()
+  const conversationId = String(peer.conversationId || '').trim()
+  const origin = normalizeOrigin(job.origin)
+  if (origin?.kind !== 'im' || origin.peer?.botId !== botId) return false
+  if (conversationKey && origin.peer.conversationKey === conversationKey) return true
+  if (conversationId && origin.peer.conversationId === conversationId) return true
+  return false
+}
+
 const IM_MAX_CHARS = 3500
 
 /**
@@ -522,14 +559,17 @@ export async function mirrorRunToSession(job, summary, deps = {}) {
   }
 
   const text = formatRunResultBody(job, summary)
+  const safe = text.replaceAll('</system-reminder>', '<\\/system-reminder>')
   const plugin = typeof deps.pluginName === 'string' && deps.pluginName.trim()
     ? deps.pluginName.trim()
     : 'dsh-ops-cron'
   const id = typeof deps.newId === 'function' ? deps.newId() : `cron-mirror-${Date.now()}`
+  // Keep role=user + user/message (assistant/message requires model source + open turn).
+  // Wrap as system-reminder so the next model turn does not treat cron output as user intent.
   const message = {
     id,
     role: 'user',
-    content: [{ type: 'text', text }],
+    content: [{ type: 'text', text: `<system-reminder>\n${safe}\n</system-reminder>` }],
     source: { kind: 'plugin', plugin },
   }
 
diff --git a/lib/host.js b/lib/host.js
index a1c1412..0eeb026 100644
--- a/lib/host.js
+++ b/lib/host.js
@@ -178,9 +178,11 @@ export function createHostService(options = {}) {
 
   async function createJob(input) {
     const t = now()
+    // Ignore client-supplied ids on create — otherwise POST/tools can overwrite.
+    const { id: _ignoredId, ...safeInput } = input && typeof input === 'object' ? input : {}
     let created
     await withState((current) => {
-      created = createJobRecord(input, current, t)
+      created = createJobRecord(safeInput, current, t)
       return upsertJob(current, created)
     })
     return jobView(created)
@@ -389,6 +391,7 @@ export function createHostService(options = {}) {
       }
 
       if (path === `${API_PREFIX}/settings` && method === 'GET') {
+        if (!isTrustedApiRequest(req)) return write(403, { ok: false, error: 'forbidden' })
         const state = await snapshot()
         write(200, { ok: true, settings: state.settings })
         return
@@ -403,6 +406,7 @@ export function createHostService(options = {}) {
       }
 
       if (path === `${API_PREFIX}/models` && method === 'GET') {
+        if (!isTrustedApiRequest(req)) return write(403, { ok: false, error: 'forbidden' })
         const catalog = typeof sessionPort?.listModels === 'function'
           ? await sessionPort.listModels()
           : { groups: [], current: null }
@@ -411,6 +415,7 @@ export function createHostService(options = {}) {
       }
 
       if (path === `${API_PREFIX}/presets` && method === 'GET') {
+        if (!isTrustedApiRequest(req)) return write(403, { ok: false, error: 'forbidden' })
         const catalog = typeof sessionPort?.listPresets === 'function'
           ? await sessionPort.listPresets()
           : { items: [], current: null }
@@ -419,6 +424,7 @@ export function createHostService(options = {}) {
       }
 
       if (path === `${API_PREFIX}/workspaces` && method === 'GET') {
+        if (!isTrustedApiRequest(req)) return write(403, { ok: false, error: 'forbidden' })
         const workspaces = typeof sessionPort?.listWorkspaces === 'function'
           ? await sessionPort.listWorkspaces()
           : []
@@ -427,6 +433,7 @@ export function createHostService(options = {}) {
       }
 
       if (path === `${API_PREFIX}/im-catalog` && method === 'GET') {
+        if (!isTrustedApiRequest(req)) return write(403, { ok: false, error: 'forbidden' })
         const dshIm = getDshIm()
         if (!dshIm || typeof dshIm.listDeliveryCatalog !== 'function') {
           write(200, {
@@ -456,6 +463,7 @@ export function createHostService(options = {}) {
       }
 
       if (path === `${API_PREFIX}/jobs` && method === 'GET') {
+        if (!isTrustedApiRequest(req)) return write(403, { ok: false, error: 'forbidden' })
         const state = await snapshot()
         write(200, { ok: true, jobs: listJobs(state).map(jobView) })
         return
@@ -474,6 +482,7 @@ export function createHostService(options = {}) {
         const jobId = decodeURIComponent(jobMatch[1])
         const rest = jobMatch[2] || ''
         if (method === 'GET' && !rest) {
+          if (!isTrustedApiRequest(req)) return write(403, { ok: false, error: 'forbidden' })
           const state = await snapshot()
           const job = getJob(state, jobId)
           if (!job) return write(404, { ok: false, error: 'job not found' })
@@ -545,6 +554,7 @@ export function createHostService(options = {}) {
       }
 
       if (path === `${API_PREFIX}/history` && method === 'GET') {
+        if (!isTrustedApiRequest(req)) return write(403, { ok: false, error: 'forbidden' })
         const state = await snapshot()
         const jobId = url.searchParams.get('jobId') || undefined
         write(200, { ok: true, runs: listHistory(state, jobId).map(runView) })
@@ -552,6 +562,7 @@ export function createHostService(options = {}) {
       }
 
       if (path === `${API_PREFIX}/preview` && method === 'POST') {
+        if (!isTrustedApiRequest(req)) return write(403, { ok: false, error: 'forbidden' })
         const body = await readJsonBody(req)
         const settings = (await snapshot()).settings
         const schedule = validateSchedule(body.schedule || body, body.timezone || settings.timezone)
@@ -561,6 +572,7 @@ export function createHostService(options = {}) {
       }
 
       if (path === `${API_PREFIX}/workspace-visible` && method === 'GET') {
+        if (!isTrustedApiRequest(req)) return write(403, { ok: false, error: 'forbidden' })
         const state = await snapshot()
         const listed = url.searchParams.getAll('id')
         write(200, {
@@ -601,6 +613,10 @@ export function createHostService(options = {}) {
     async listJobs() {
       return listJobs(await snapshot()).map(jobView)
     },
+    async getJob(jobId) {
+      const job = getJob(await snapshot(), jobId)
+      return job ? jobView(job) : null
+    },
     async listHistory(jobId) {
       return listHistory(await snapshot(), jobId).map(runView)
     },
diff --git a/lib/index.d.ts b/lib/index.d.ts
index 6794c52..3c3abfb 100644
--- a/lib/index.d.ts
+++ b/lib/index.d.ts
@@ -46,6 +46,8 @@ export function normalizeOrigin(input?: object): { kind: 'web' | 'im', sessionId
 export function resolveCreateDelivery(args?: object, exec?: object, deps?: object): Promise<{ kind: 'dsh' | 'im', botId?: string, targetId?: string }>
 export function resolveCreateOrigin(args?: object, exec?: object, deps?: object): Promise<{ kind: 'web' | 'im', sessionId?: string, peer?: object } | null>
 export function resolveMirrorSession(job: object, deps?: object): Promise<{ sessionId: string, via: string } | null>
+export function resolveCallerPeer(exec?: object, dshIm?: object): Promise<object | null>
+export function jobVisibleToPeer(job: object, peer: object): boolean
 export function formatRunResultBody(job: object, summary?: string): string
 export function deliverRunToIm(job: object, summary?: string, deps?: object): Promise<object>
 export function mirrorRunToSession(job: object, summary?: string, deps?: object): Promise<object>
diff --git a/lib/index.js b/lib/index.js
index 3c2afb6..75312a3 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -52,9 +52,11 @@ export { claimOccurrence, executeClaimedRun, extractAssistantText, TITLE_PREFIX
 export {
   deliverRunToIm,
   formatRunResultBody,
+  jobVisibleToPeer,
   mirrorRunToSession,
   normalizeDelivery,
   normalizeOrigin,
+  resolveCallerPeer,
   resolveCreateDelivery,
   resolveCreateOrigin,
   resolveMirrorSession,
diff --git a/lib/tools.js b/lib/tools.js
index b88376b..79a8b29 100644
--- a/lib/tools.js
+++ b/lib/tools.js
@@ -4,7 +4,13 @@
  */
 
 import { formatInZone, resolveTodayAt } from './scheduler.js'
-import { deliveryLine, resolveCreateDelivery, resolveCreateOrigin } from './delivery.js'
+import {
+  deliveryLine,
+  jobVisibleToPeer,
+  resolveCallerPeer,
+  resolveCreateDelivery,
+  resolveCreateOrigin,
+} from './delivery.js'
 import { resolveCreateAgentPreset } from './preset.js'
 
 const JOB_SCHEMA = {
@@ -107,10 +113,35 @@ export function callerWorkingDirectory(exec) {
   return String(session?.header?.cwd || session?.cwd || exec?.agent?.cwd || '').trim()
 }
 
-export function resolveCreateCwd(args, exec) {
+export function resolveCreateCwd(args, exec, { peer = null } = {}) {
+  const sessionCwd = callerWorkingDirectory(exec)
   const passed = typeof args?.cwd === 'string' ? args.cwd.trim() : ''
+  // IM peers cannot point scheduled Agents at arbitrary host paths.
+  if (peer?.botId) return sessionCwd
   if (passed) return passed
-  return callerWorkingDirectory(exec)
+  return sessionCwd
+}
+
+function forbidForeignJob(job, peer) {
+  if (!peer?.botId) return job
+  if (jobVisibleToPeer(job, peer)) return job
+  const error = new Error('job not found or not owned by this chat')
+  error.code = 'NOT_FOUND'
+  throw error
+}
+
+async function requireOwnedJob(service, id, peer) {
+  const job = await service.getJob?.(id)
+  if (job) return forbidForeignJob(job, peer)
+  // Fallback when getJob is absent: list and find.
+  const jobs = await service.listJobs()
+  const hit = (jobs || []).find((row) => row.id === id)
+  if (!hit) {
+    const error = new Error('job not found')
+    error.code = 'NOT_FOUND'
+    throw error
+  }
+  return forbidForeignJob(hit, peer)
 }
 
 export function callerModelSelection(exec) {
@@ -165,15 +196,15 @@ export function cronToolDefinitions(service, deps = {}) {
           minute: { type: 'integer', description: '0-59, used with hour.' },
           timezone: { type: 'string', description: 'IANA timezone for expr/at. Default Asia/Shanghai. Do not pass UTC unless the user asked for UTC.' },
           time_zone: { type: 'string', description: 'Alias of timezone.' },
-          cwd: { type: 'string', description: 'Filesystem path of the workspace this job should run in. When the user is in a workspace conversation, pass THAT workspace path (current session cwd). If omitted, the current session cwd is used. Only skip this to isolate from the project if the user asked for a custom folder.' },
+          cwd: { type: 'string', description: 'Filesystem path of the workspace this job should run in. When the user is in a workspace conversation, pass THAT workspace path (current session cwd). If omitted, the current session cwd is used. WhatsApp/IM creates always use the current session cwd.' },
           provider: { type: 'string', description: 'Provider route for this job (e.g. minimax-cn, deepseek). Must be passed with model. If omitted, the current session model is stored so quota stays predictable.' },
           model: { type: 'string', description: 'Model id for this job. Must be passed with provider. Scheduled runs bill this model.' },
           reasoning_effort: { type: 'string', description: 'Optional reasoning effort for this job.' },
           timeout_minutes: { type: 'integer', description: 'Per-run timeout in minutes, 1-240.' },
           enabled: { type: 'boolean', description: 'If false, create paused. Default true.' },
-          delivery: { type: 'string', description: 'dsh (sidebar session) or im (proactive WhatsApp/IM via botId+targetId). Omit to auto-detect from the current session.' },
-          im_bot_id: { type: 'string', description: 'Opaque botId from IM 投递设置 when delivery=im.' },
-          im_target_id: { type: 'string', description: 'Opaque targetId from IM 投递设置 when delivery=im.' },
+          delivery: { type: 'string', description: 'dsh (sidebar session) or im (proactive WhatsApp/IM via botId+targetId). Omit to auto-detect from the current session. On WhatsApp/IM, delivery is always bound to the current chat — free im_bot_id/im_target_id are ignored.' },
+          im_bot_id: { type: 'string', description: 'Opaque botId from IM 投递设置 when delivery=im (Web/sidebar only; IM chats cannot retarget).' },
+          im_target_id: { type: 'string', description: 'Opaque targetId from IM 投递设置 when delivery=im (Web/sidebar only; IM chats cannot retarget).' },
           agent_preset: { type: 'string', description: 'Agent preset id for scheduled runs. Omit to inherit from the current WhatsApp/IM chat or Host default.' },
         },
         required: ['name', 'prompt'],
@@ -203,18 +234,20 @@ export function cronToolDefinitions(service, deps = {}) {
       async execute(args, exec) {
         aborted(exec)
         const timeout = Number(args.timeout_minutes)
+        const dshIm = getDshIm()
         try {
-          const delivery = await resolveCreateDelivery(args, exec, { dshIm: getDshIm() })
-          const origin = await resolveCreateOrigin(args, exec, { dshIm: getDshIm() })
+          const peer = await resolveCallerPeer(exec, dshIm)
+          const delivery = await resolveCreateDelivery(args, exec, { dshIm })
+          const origin = await resolveCreateOrigin(args, exec, { dshIm })
           const agentPreset = await resolveCreateAgentPreset(args, exec, {
-            dshIm: getDshIm(),
+            dshIm,
             agentPresets: getAgentPresets(),
           })
           const job = await service.createJob({
             name: args.name,
             prompt: args.prompt,
             schedule: scheduleFromArgs(args, Date.now()),
-            cwd: resolveCreateCwd(args, exec),
+            cwd: resolveCreateCwd(args, exec, { peer }),
             ...resolveCreateModel(args, exec),
             timeoutMinutes: Number.isFinite(timeout) && timeout > 0 ? timeout : undefined,
             enabled: args.enabled !== false,
@@ -263,7 +296,9 @@ export function cronToolDefinitions(service, deps = {}) {
       presentCall: () => ({ card: 'generic', title: '列出定时任务' }),
       async execute(args, exec) {
         aborted(exec)
+        const peer = await resolveCallerPeer(exec, getDshIm())
         let jobs = await service.listJobs()
+        if (peer?.botId) jobs = jobs.filter((job) => jobVisibleToPeer(job, peer))
         if (args?.enabled_only === true) jobs = jobs.filter((job) => job.enabled !== false)
         return { jobs, count: jobs.length }
       },
@@ -284,7 +319,10 @@ export function cronToolDefinitions(service, deps = {}) {
       presentCall: (args) => ({ card: 'generic', title: '暂停定时任务', content: String(args?.id || '') }),
       async execute(args, exec) {
         aborted(exec)
-        const job = await service.pauseJob(requireId(args), false)
+        const peer = await resolveCallerPeer(exec, getDshIm())
+        const id = requireId(args)
+        await requireOwnedJob(service, id, peer)
+        const job = await service.pauseJob(id, false)
         return { job }
       },
     },
@@ -304,7 +342,10 @@ export function cronToolDefinitions(service, deps = {}) {
       presentCall: (args) => ({ card: 'generic', title: '恢复定时任务', content: String(args?.id || '') }),
       async execute(args, exec) {
         aborted(exec)
-        const job = await service.pauseJob(requireId(args), true)
+        const peer = await resolveCallerPeer(exec, getDshIm())
+        const id = requireId(args)
+        await requireOwnedJob(service, id, peer)
+        const job = await service.pauseJob(id, true)
         return { job }
       },
     },
@@ -332,8 +373,10 @@ export function cronToolDefinitions(service, deps = {}) {
       presentCall: (args) => ({ card: 'generic', title: '删除定时任务', content: String(args?.id || '') }),
       async execute(args, exec) {
         aborted(exec)
+        const peer = await resolveCallerPeer(exec, getDshIm())
         const id = requireId(args)
         try {
+          await requireOwnedJob(service, id, peer)
           await service.deleteJob(id)
           return { id, deleted: true }
         } catch (error) {
diff --git a/test/delivery.test.js b/test/delivery.test.js
index 631bce9..f973c10 100644
--- a/test/delivery.test.js
+++ b/test/delivery.test.js
@@ -10,6 +10,7 @@ import {
   formatRunResultBody,
   deliverRunToIm,
   mirrorRunToSession,
+  jobVisibleToPeer,
 } from '../lib/delivery.js'
 
 test('normalizeDelivery defaults to dsh', () => {
@@ -307,10 +308,75 @@ test('mirrorRunToSession appends plugin notice without waking a turn', async ()
   assert.equal(appended[0][0], 'user/message')
   assert.match(appended[0][1].content[0].text, /日报/)
   assert.match(appended[0][1].content[0].text, /line one/)
+  assert.match(appended[0][1].content[0].text, /<system-reminder>/)
   assert.equal(appended[0][1].source.kind, 'plugin')
   assert.deepEqual(appended[0][2], { surfaceOp: 'append' })
 })
 
+test('matchTargetForPeer requires exact JID equality', () => {
+  const targets = [{
+    targetId: 'suffix-trap',
+    kind: 'user',
+    route: { jid: '8613800138000@s.whatsapp.net' },
+  }]
+  const peer = {
+    kind: 'direct',
+    conversationId: '13800138000@s.whatsapp.net',
+    phone: '13800138000',
+  }
+  assert.equal(matchTargetForPeer(targets, peer), null)
+})
+
+test('jobVisibleToPeer scopes IM ownership to origin conversation', () => {
+  const peer = {
+    botId: 'bot-a',
+    conversationKey: 'group:120363@g.us:user:1@lid',
+    conversationId: '120363@g.us',
+  }
+  assert.equal(jobVisibleToPeer({
+    origin: {
+      kind: 'im',
+      peer: { botId: 'bot-a', conversationKey: 'group:120363@g.us:user:1@lid', conversationId: '120363@g.us' },
+    },
+  }, peer), true)
+  assert.equal(jobVisibleToPeer({
+    origin: {
+      kind: 'im',
+      peer: { botId: 'bot-a', conversationKey: 'group:other@g.us', conversationId: 'other@g.us' },
+    },
+  }, peer), false)
+  assert.equal(jobVisibleToPeer({
+    origin: { kind: 'web', sessionId: 'web-1' },
+  }, peer), false)
+})
+
+test('resolveCreateDelivery binds IM peers to the current chat', async () => {
+  const peer = {
+    botId: 'bot-a',
+    conversationKey: 'direct:86138@s.whatsapp.net',
+    conversationId: '86138@s.whatsapp.net',
+    kind: 'direct',
+    phone: '86138',
+  }
+  const delivery = await resolveCreateDelivery(
+    { delivery: 'im', im_bot_id: 'other-bot', im_target_id: 'other-target' },
+    { agent: { session: { id: 'sess-im' } } },
+    {
+      dshIm: {
+        resolveSessionPeer: async () => peer,
+        listTargets: async () => [{
+          targetId: 'auto-dm',
+          kind: 'user',
+          route: { jid: '86138@s.whatsapp.net' },
+        }],
+      },
+    },
+  )
+  assert.equal(delivery.kind, 'im')
+  assert.equal(delivery.botId, 'bot-a')
+  assert.equal(delivery.targetId, 'auto-dm')
+})
+
 test('mirrorRunToSession resumes a cold origin session instead of create', async () => {
   const appended = []
   const resumed = []
diff --git a/test/host.test.js b/test/host.test.js
index 89c263a..a77bd24 100644
--- a/test/host.test.js
+++ b/test/host.test.js
@@ -237,6 +237,30 @@ test('shipped HTTP handler: create, list, run-now, history', async (t) => {
   assert.deepEqual(visible.body.visible, ['other'])
 })
 
+test('createJob ignores client-supplied id to prevent overwrite', async (t) => {
+  const dir = await mkdtemp(join(tmpdir(), 'dsh-ops-cron-'))
+  t.after(() => rm(dir, { recursive: true, force: true }))
+  const service = createHostService({
+    filePath: join(dir, 'store.json'),
+    now: () => Date.parse('2026-08-24T01:00:00.000Z'),
+  })
+  const first = await service.createJob({
+    name: 'keep-me',
+    prompt: 'first',
+    schedule: { kind: 'cron', expr: '0 9 * * *', timezone: 'Asia/Shanghai' },
+  })
+  const second = await service.createJob({
+    id: first.id,
+    name: 'attacker',
+    prompt: 'overwrite?',
+    schedule: { kind: 'cron', expr: '0 10 * * *', timezone: 'Asia/Shanghai' },
+  })
+  assert.notEqual(second.id, first.id)
+  const listed = await service.listJobs()
+  assert.equal(listed.find((job) => job.id === first.id)?.name, 'keep-me')
+  assert.equal(listed.find((job) => job.id === second.id)?.name, 'attacker')
+})
+
 test('POST /runs/:id/open reveals the run session id', async (t) => {
   const dir = await mkdtemp(join(tmpdir(), 'dsh-ops-cron-'))
   t.after(() => rm(dir, { recursive: true, force: true }))