diff --git a/mateclaw-ui/src/components/skill/PreflightInstallDialog.vue b/mateclaw-ui/src/components/skill/PreflightInstallDialog.vue
new file mode 100644
index 00000000..98519241
--- /dev/null
+++ b/mateclaw-ui/src/components/skill/PreflightInstallDialog.vue
@@ -0,0 +1,245 @@
+<template>
+  <div v-if="visible" class="modal-overlay" @click.self="handleClose">
+    <div class="preflight-modal">
+      <div class="modal-header">
+        <h2>{{ t('skills.preflight.title') }}: {{ skillName }}</h2>
+        <button class="modal-close" @click="handleClose">
+          <svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
+            <line x1="18" y1="6" x2="6" y2="18"/><line x1="6" y1="6" x2="18" y2="18"/>
+          </svg>
+        </button>
+      </div>
+
+      <div class="modal-body">
+        <p v-if="loading" class="loading">{{ t('common.loading') }}</p>
+
+        <template v-else>
+          <!-- Status summary -->
+          <div class="status-banner" :class="statusBannerClass">
+            <span class="status-icon">{{ allMet ? '✅' : '⚙️' }}</span>
+            <div class="status-text">
+              <strong>
+                {{ allMet ? t('skills.preflight.allMet') : t('skills.preflight.setupNeeded', { count: missingCount }) }}
+              </strong>
+              <p>{{ allMet ? t('skills.preflight.allMetDesc') : t('skills.preflight.setupNeededDesc') }}</p>
+            </div>
+          </div>
+
+          <!-- Requirement list -->
+          <div v-if="statuses.length > 0" class="req-list">
+            <h3>{{ t('skills.preflight.requirements') }}</h3>
+            <div v-for="req in statuses" :key="req.key" class="req-item" :class="{ 'req-ok': req.satisfied, 'req-missing': !req.satisfied && !req.optional, 'req-optional': req.optional }">
+              <div class="req-head">
+                <span class="req-icon">{{ req.satisfied ? '✓' : (req.optional ? '○' : '✗') }}</span>
+                <span class="req-name">{{ req.key }}</span>
+                <span v-if="req.type" class="req-type">{{ req.type }}</span>
+                <span v-if="req.optional" class="req-optional-tag">{{ t('skills.preflight.optional') }}</span>
+              </div>
+              <p v-if="req.description" class="req-desc">{{ req.description }}</p>
+              <!-- Install commands per platform -->
+              <div v-if="!req.satisfied && req.installCommands && Object.keys(req.installCommands).length > 0" class="install-cmds">
+                <div class="install-cmds-head">{{ t('skills.preflight.installCommands') }}</div>
+                <div v-for="(cmd, platform) in req.installCommands" :key="platform" class="install-cmd-row">
+                  <span class="platform-tag" :class="`platform-${platformClass(platform)}`">{{ formatPlatform(platform) }}</span>
+                  <code class="install-cmd">{{ cmd }}</code>
+                  <button class="copy-btn" :title="t('common.copy')" @click="copy(String(cmd))">📋</button>
+                </div>
+              </div>
+            </div>
+          </div>
+
+          <!-- Feature matrix -->
+          <div v-if="featureRows.length > 0" class="feat-section">
+            <h3>{{ t('skills.preflight.features') }}</h3>
+            <div v-for="row in featureRows" :key="row.id" class="feat-item">
+              <span class="feat-id">{{ row.id }}</span>
+              <span class="feat-status" :class="`feat-${row.status.toLowerCase()}`">{{ row.status }}</span>
+            </div>
+          </div>
+
+          <!-- Empty manifest fallback -->
+          <p v-if="statuses.length === 0 && featureRows.length === 0" class="empty-msg">
+            {{ summary || t('skills.preflight.noManifest') }}
+          </p>
+        </template>
+      </div>
+
+      <div class="modal-footer">
+        <button class="btn-secondary" @click="handleClose">{{ t('common.close') }}</button>
+        <button v-if="!allMet" class="btn-secondary" @click="reload" :disabled="loading">
+          {{ loading ? t('common.loading') : t('skills.preflight.recheck') }}
+        </button>
+      </div>
+    </div>
+  </div>
+</template>
+
+<script setup lang="ts">
+import { computed, ref, watch } from 'vue'
+import { useI18n } from 'vue-i18n'
+import { ElMessage } from 'element-plus'
+import { skillApi } from '@/api/index'
+
+interface RequirementStatus {
+  key: string
+  type?: string
+  description?: string
+  optional?: boolean
+  status?: string
+  satisfied?: boolean
+  installCommands?: Record<string, string>
+}
+
+const props = defineProps<{
+  visible: boolean
+  skillId: number | string | null
+  skillName: string
+}>()
+const emit = defineEmits<{
+  (e: 'update:visible', value: boolean): void
+}>()
+
+const { t } = useI18n()
+const loading = ref(false)
+const allMet = ref(false)
+const statuses = ref<RequirementStatus[]>([])
+const summary = ref('')
+const featureStatuses = ref<Record<string, string>>({})
+const activeFeatures = ref<string[]>([])
+
+const missingCount = computed(() =>
+  statuses.value.filter(s => !s.satisfied && !s.optional).length,
+)
+const statusBannerClass = computed(() => allMet.value ? 'banner-ok' : 'banner-needs-setup')
+
+const featureRows = computed(() =>
+  Object.entries(featureStatuses.value).map(([id, status]) => ({ id, status })),
+)
+
+watch(() => props.visible, (v) => {
+  if (v && props.skillId != null) reload()
+})
+
+async function reload() {
+  if (props.skillId == null) return
+  loading.value = true
+  try {
+    const res: any = await skillApi.requirements(props.skillId)
+    const data = res?.data || {}
+    allMet.value = !!data.allMet
+    statuses.value = Array.isArray(data.statuses) ? data.statuses : []
+    summary.value = data.summary || ''
+    featureStatuses.value = data.featureStatuses || {}
+    activeFeatures.value = Array.isArray(data.activeFeatures) ? data.activeFeatures : []
+  } catch (e: any) {
+    ElMessage.error(typeof e === 'string' ? e : e?.message || t('skills.preflight.loadFailed'))
+    statuses.value = []
+    allMet.value = false
+  } finally {
+    loading.value = false
+  }
+}
+
+function handleClose() {
+  emit('update:visible', false)
+}
+
+async function copy(cmd: string) {
+  try {
+    if (navigator.clipboard) {
+      await navigator.clipboard.writeText(cmd)
+    } else {
+      // Fallback for clipboard-API-disabled contexts (eg http://). The
+      // textarea trick is broadly supported and avoids a noisy permission
+      // failure on the production-ish workflow.
+      const ta = document.createElement('textarea')
+      ta.value = cmd
+      ta.style.position = 'fixed'
+      ta.style.left = '-9999px'
+      document.body.appendChild(ta)
+      ta.select()
+      document.execCommand('copy')
+      document.body.removeChild(ta)
+    }
+    ElMessage.success(t('common.copied'))
+  } catch {
+    ElMessage.warning(t('common.copyFailed'))
+  }
+}
+
+function platformClass(platform: string): string {
+  const p = String(platform).toLowerCase()
+  if (p.includes('mac')) return 'mac'
+  if (p.includes('linux') || p.includes('apt') || p.includes('dnf') || p.includes('yum')) return 'linux'
+  if (p.includes('win')) return 'win'
+  return 'other'
+}
+
+function formatPlatform(platform: string): string {
+  const p = String(platform).toLowerCase()
+  if (p === 'macos') return 'macOS'
+  if (p === 'linux_apt') return 'Linux (apt)'
+  if (p === 'linux_dnf') return 'Linux (dnf)'
+  if (p === 'windows') return 'Windows'
+  if (p === 'manual_url') return 'Manual'
+  return String(platform)
+}
+</script>
+
+<style scoped>
+.modal-overlay { position: fixed; inset: 0; background: rgba(0, 0, 0, 0.45); display: flex; align-items: center; justify-content: center; z-index: 1100; padding: 20px; }
+.preflight-modal { background: var(--mc-bg-elevated); border: 1px solid var(--mc-border); border-radius: 16px; width: 100%; max-width: 720px; max-height: 90vh; display: flex; flex-direction: column; box-shadow: 0 24px 64px rgba(0, 0, 0, 0.18); }
+.modal-header { display: flex; align-items: center; justify-content: space-between; padding: 18px 22px; border-bottom: 1px solid var(--mc-border-light); }
+.modal-header h2 { font-size: 17px; font-weight: 600; margin: 0; color: var(--mc-text-primary); }
+.modal-close { width: 30px; height: 30px; border: none; background: none; cursor: pointer; color: var(--mc-text-tertiary); border-radius: 6px; display: flex; align-items: center; justify-content: center; }
+.modal-close:hover { background: var(--mc-bg-sunken); }
+.modal-body { flex: 1; overflow-y: auto; padding: 18px 22px; display: flex; flex-direction: column; gap: 14px; }
+.modal-footer { display: flex; justify-content: flex-end; gap: 10px; padding: 14px 22px; border-top: 1px solid var(--mc-border-light); }
+.btn-secondary { padding: 8px 14px; background: var(--mc-bg-elevated); color: var(--mc-text-primary); border: 1px solid var(--mc-border); border-radius: 10px; font-size: 13px; cursor: pointer; }
+.btn-secondary:hover { background: var(--mc-bg-sunken); }
+.btn-secondary:disabled { opacity: 0.6; cursor: not-allowed; }
+
+.loading { color: var(--mc-text-tertiary); }
+.empty-msg { color: var(--mc-text-tertiary); font-size: 13px; }
+
+.status-banner { display: flex; align-items: flex-start; gap: 12px; padding: 14px; border-radius: 12px; }
+.banner-ok { background: rgba(34, 197, 94, 0.08); border: 1px solid rgba(34, 197, 94, 0.2); }
+.banner-needs-setup { background: var(--mc-primary-bg); border: 1px solid rgba(217, 109, 70, 0.18); }
+.status-icon { font-size: 22px; line-height: 1; }
+.status-text strong { display: block; font-size: 14px; font-weight: 600; color: var(--mc-text-primary); margin-bottom: 2px; }
+.status-text p { margin: 0; font-size: 12px; color: var(--mc-text-secondary); line-height: 1.5; }
+
+.req-list h3, .feat-section h3 { font-size: 12px; font-weight: 700; color: var(--mc-text-secondary); text-transform: uppercase; letter-spacing: 0.06em; margin: 0 0 6px; }
+.req-item { padding: 10px 12px; border-radius: 10px; border: 1px solid var(--mc-border-light); margin-bottom: 6px; background: var(--mc-bg-muted); }
+.req-item.req-ok { border-color: rgba(34, 197, 94, 0.2); }
+.req-item.req-missing { border-color: rgba(217, 109, 70, 0.25); }
+.req-head { display: flex; align-items: center; gap: 8px; }
+.req-icon { font-weight: 700; }
+.req-ok .req-icon { color: #16a34a; }
+.req-missing .req-icon { color: var(--mc-danger); }
+.req-optional .req-icon { color: var(--mc-text-tertiary); }
+.req-name { font-family: 'JetBrains Mono', 'Fira Code', 'Consolas', monospace; font-size: 13px; font-weight: 600; color: var(--mc-text-primary); }
+.req-type { font-size: 10px; padding: 1px 6px; background: var(--mc-bg-sunken); color: var(--mc-text-tertiary); border-radius: 999px; font-weight: 600; text-transform: uppercase; letter-spacing: 0.04em; }
+.req-optional-tag { font-size: 10px; padding: 1px 6px; background: var(--mc-bg-sunken); color: var(--mc-text-tertiary); border-radius: 999px; font-weight: 600; }
+.req-desc { margin: 6px 0 0; font-size: 12px; color: var(--mc-text-secondary); line-height: 1.5; }
+.install-cmds { margin-top: 8px; }
+.install-cmds-head { font-size: 11px; font-weight: 700; color: var(--mc-text-tertiary); text-transform: uppercase; letter-spacing: 0.06em; margin-bottom: 4px; }
+.install-cmd-row { display: flex; align-items: center; gap: 8px; padding: 4px 0; }
+.platform-tag { font-size: 10px; padding: 1px 6px; border-radius: 4px; font-weight: 700; text-transform: uppercase; letter-spacing: 0.04em; min-width: 64px; text-align: center; }
+.platform-mac { background: rgba(99, 102, 241, 0.12); color: #6366f1; }
+.platform-linux { background: rgba(34, 197, 94, 0.12); color: #16a34a; }
+.platform-win { background: rgba(59, 130, 246, 0.12); color: #3b82f6; }
+.platform-other { background: var(--mc-bg-sunken); color: var(--mc-text-tertiary); }
+.install-cmd { flex: 1; font-family: 'JetBrains Mono', 'Fira Code', 'Consolas', monospace; font-size: 12px; padding: 4px 8px; background: var(--mc-bg-sunken); border-radius: 4px; color: var(--mc-text-primary); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
+.copy-btn { width: 26px; height: 26px; border: none; background: none; cursor: pointer; border-radius: 4px; font-size: 14px; }
+.copy-btn:hover { background: var(--mc-bg-sunken); }
+
+.feat-section { display: flex; flex-direction: column; gap: 4px; }
+.feat-item { display: flex; align-items: center; justify-content: space-between; padding: 6px 10px; background: var(--mc-bg-muted); border-radius: 8px; font-size: 12px; }
+.feat-id { font-family: 'JetBrains Mono', 'Fira Code', 'Consolas', monospace; color: var(--mc-text-primary); }
+.feat-status { font-size: 10px; padding: 1px 6px; border-radius: 999px; font-weight: 700; letter-spacing: 0.04em; }
+.feat-ready { background: rgba(34, 197, 94, 0.12); color: #16a34a; }
+.feat-setup_needed { background: var(--mc-primary-bg); color: var(--mc-primary-hover); }
+.feat-unsupported { background: var(--mc-bg-sunken); color: var(--mc-text-tertiary); }
+.feat-unknown { background: var(--mc-bg-sunken); color: var(--mc-text-tertiary); }
+</style>
diff --git a/mateclaw-ui/src/i18n/locales/en-US.ts b/mateclaw-ui/src/i18n/locales/en-US.ts
index 2823bbed..749bae1d 100644
--- a/mateclaw-ui/src/i18n/locales/en-US.ts
+++ b/mateclaw-ui/src/i18n/locales/en-US.ts
@@ -17,6 +17,7 @@ export default {
     view: 'View',
     copy: 'Copy',
     copied: 'Copied',
+    copyFailed: 'Copy failed',
     confirm: 'Confirm',
     close: 'Close',
     add: 'Add',
@@ -2006,10 +2007,25 @@ export default {
     actions: {
       configure: 'Configure',
       view: 'View',
+      setUp: 'Set Up',
       delete: 'Delete',
       saveChanges: 'Save Changes',
       createSkill: 'Create Skill',
     },
+    preflight: {
+      title: 'Pre-flight check',
+      allMet: 'All requirements satisfied',
+      allMetDesc: 'This skill is ready to use as soon as you bind it to an agent.',
+      setupNeeded: '{count} requirement(s) need attention',
+      setupNeededDesc: 'Install the missing pieces below, then re-check or re-resolve the skill.',
+      requirements: 'Requirements',
+      features: 'Features',
+      installCommands: 'Install commands',
+      optional: 'Optional',
+      noManifest: 'This skill has no v3 manifest. Status falls back to legacy dependency reporting.',
+      recheck: 'Re-check',
+      loadFailed: 'Failed to load preflight data',
+    },
     detail: {
       title: 'Skill detail',
       manifest: 'Manifest',
diff --git a/mateclaw-ui/src/i18n/locales/zh-CN.ts b/mateclaw-ui/src/i18n/locales/zh-CN.ts
index 892584b9..69bc1413 100644
--- a/mateclaw-ui/src/i18n/locales/zh-CN.ts
+++ b/mateclaw-ui/src/i18n/locales/zh-CN.ts
@@ -17,6 +17,7 @@ export default {
     view: '查看',
     copy: '复制',
     copied: '已复制',
+    copyFailed: '复制失败',
     confirm: '确认',
     close: '关闭',
     add: '添加',
@@ -2008,10 +2009,25 @@ export default {
     actions: {
       configure: '配置',
       view: '查看',
+      setUp: '配置就绪',
       delete: '删除',
       saveChanges: '保存更改',
       createSkill: '创建技能',
     },
+    preflight: {
+      title: '装前检查',
+      allMet: '所有依赖已满足',
+      allMetDesc: '该 skill 已就绪，绑定到 agent 即可使用。',
+      setupNeeded: '{count} 项依赖待处理',
+      setupNeededDesc: '按下方提示安装所需依赖，安装完成后点重新检查。',
+      requirements: '依赖项',
+      features: '特性',
+      installCommands: '安装命令',
+      optional: '可选',
+      noManifest: '该 skill 未提供 v3 manifest，状态回退到旧依赖检查模式。',
+      recheck: '重新检查',
+      loadFailed: '加载预检数据失败',
+    },
     detail: {
       title: '技能详情',
       manifest: 'Manifest',
diff --git a/mateclaw-ui/src/views/SkillMarket.vue b/mateclaw-ui/src/views/SkillMarket.vue
index 69bde54f..5c0abc87 100644
--- a/mateclaw-ui/src/views/SkillMarket.vue
+++ b/mateclaw-ui/src/views/SkillMarket.vue
@@ -198,6 +198,14 @@
         <div class="skill-footer">
           <span v-if="skill.author" class="skill-author">by {{ skill.author }}</span>
           <div class="skill-actions">
+            <!-- RFC-090 §4.2 [Set Up] — surfaced when card is Setup
+                 Needed; opens the preflight dialog with install hints -->
+            <button v-if="needsSetup(skill)" class="skill-btn skill-btn-setup" @click="openPreflight(skill)">
+              <svg width="13" height="13" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
+                <circle cx="12" cy="12" r="3"/><path d="M19.4 15a1.65 1.65 0 0 0 .33 1.82l.06.06a2 2 0 1 1-2.83 2.83l-.06-.06a1.65 1.65 0 0 0-1.82-.33 1.65 1.65 0 0 0-1 1.51V21a2 2 0 1 1-4 0v-.09a1.65 1.65 0 0 0-1-1.51 1.65 1.65 0 0 0-1.82.33l-.06.06a2 2 0 1 1-2.83-2.83l.06-.06a1.65 1.65 0 0 0 .33-1.82 1.65 1.65 0 0 0-1.51-1H3a2 2 0 1 1 0-4h.09a1.65 1.65 0 0 0 1.51-1 1.65 1.65 0 0 0-.33-1.82l-.06-.06a2 2 0 1 1 2.83-2.83l.06.06a1.65 1.65 0 0 0 1.82.33H9a1.65 1.65 0 0 0 1-1.51V3a2 2 0 1 1 4 0v.09a1.65 1.65 0 0 0 1 1.51h.09a1.65 1.65 0 0 0 1.82-.33l.06-.06a2 2 0 1 1 2.83 2.83l-.06.06a1.65 1.65 0 0 0-.33 1.82V9c0 .66.26 1.3.73 1.77.47.47 1.11.73 1.77.73H21a2 2 0 1 1 0 4h-.09c-.66 0-1.3.26-1.77.73-.47.47-.73 1.11-.73 1.77z"/>
+              </svg>
+              {{ t('skills.actions.setUp') }}
+            </button>
             <button class="skill-btn" @click="openDetailDrawer(skill)">
               <svg width="13" height="13" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
                 <circle cx="12" cy="12" r="3"/><path d="M2 12s3-7 10-7 10 7 10 7-3 7-10 7-10-7-10-7z"/>
@@ -249,6 +257,13 @@
     <!-- Import Hub Dialog -->
     <ImportHubDialog v-model:visible="showImportDialog" @installed="loadAll" />
 
+    <!-- RFC-090 §4.4 Pre-flight install dialog -->
+    <PreflightInstallDialog
+      v-model:visible="preflightVisible"
+      :skill-id="preflightSkillId"
+      :skill-name="preflightSkillName"
+    />
+
     <!-- RFC-090 Phase 3 — Skill detail drawer (Manifest / Tools / Features) -->
     <el-drawer
       v-model="detailDrawerVisible"
@@ -429,6 +444,7 @@ import { ElMessage, ElMessageBox } from 'element-plus'
 import { skillApi, skillInstallApi } from '@/api/index'
 import type { Skill, SkillRuntimeStatus, SkillSecurityFinding } from '@/types/index'
 import ImportHubDialog from '@/components/skill/ImportHubDialog.vue'
+import PreflightInstallDialog from '@/components/skill/PreflightInstallDialog.vue'
 import { useSkillName } from '@/composables/useSkillName'
 
 const { t } = useI18n()
@@ -467,6 +483,17 @@ const detailLessonsLoading = ref(false)
 const lessonsCountBySkill = ref<Record<string, number>>({})
 const usedByBySkill = ref<Record<string, number>>({})
 
+/** RFC-090 §4.4 — pre-flight dialog state. */
+const preflightVisible = ref(false)
+const preflightSkillId = ref<number | string | null>(null)
+const preflightSkillName = ref('')
+
+function openPreflight(skill: Skill) {
+  preflightSkillId.value = skill.id
+  preflightSkillName.value = resolveSkillName(skill)
+  preflightVisible.value = true
+}
+
 const detailRuntime = computed(() =>
   detailSkill.value ? runtimeStatusMap.value[detailSkill.value.name] || null : null,
 )
@@ -979,6 +1006,25 @@ function getLessonsCount(skill: Skill): number {
   return lessonsCountBySkill.value[String(skill.id)] || 0
 }
 
+/**
+ * RFC-090 §4.2 — does this skill need the [Set Up] button surfaced?
+ * Yes iff: enabled, not security-blocked, AND either:
+ *   - manifest features exist with at least one not-READY, OR
+ *   - legacy dependencyReady is false.
+ */
+function needsSetup(skill: Skill): boolean {
+  if (!skill.enabled) return false
+  const rt = getRuntimeStatus(skill)
+  if (!rt) return false
+  if (rt.securityBlocked) return false
+  if (rt.manifest && Array.isArray(rt.manifest.features) && rt.manifest.features.length > 0) {
+    const total = rt.manifest.features.length
+    const ready = (rt.activeFeatures || []).length
+    return ready < total
+  }
+  return rt.dependencyReady === false
+}
+
 function getUsedByCount(skill: Skill): number {
   return usedByBySkill.value[String(skill.id)] || 0
 }
@@ -1292,6 +1338,10 @@ html.dark .scan-finding-item { background: rgba(255, 255, 255, 0.05); }
 .usedby-badge, .lessons-badge { padding: 2px 8px; border-radius: 999px; font-size: 11px; font-weight: 600; background: var(--mc-bg-sunken); color: var(--mc-text-secondary); }
 .lessons-badge { cursor: pointer; }
 .lessons-badge:hover { background: var(--mc-primary-bg); color: var(--mc-primary); }
+
+/* RFC-090 §4.2 — [Set Up] button highlight */
+.skill-btn-setup { background: var(--mc-primary-bg); color: var(--mc-primary); border-color: rgba(217, 109, 70, 0.18); font-weight: 600; }
+.skill-btn-setup:hover { background: var(--mc-primary); color: white; }
 :root.dark .rt-features-ready { background: rgba(34, 197, 94, 0.2); color: #4ade80; }
 :root.dark .rt-features-mixed { background: rgba(129, 140, 248, 0.18); color: #a5b4fc; }
 .rt-disabled { background: var(--mc-bg-sunken); color: var(--mc-text-tertiary); }