diff --git a/furniture-3d-system/src/lib/bom-costing/contracts.ts b/furniture-3d-system/src/lib/bom-costing/contracts.ts
index fb3e289c..3ae6be3e 100644
--- a/furniture-3d-system/src/lib/bom-costing/contracts.ts
+++ b/furniture-3d-system/src/lib/bom-costing/contracts.ts
@@ -210,10 +210,16 @@ export const bomCostingStructureComponentSlotSchema = z.object({
   role: bomCostingStructureComponentRoleSchema,
   category: bomCostingLineCategorySchema,
   partName: z.string().trim().min(1).max(200),
+  // Unit is owned by the category Skill. Keep a default only for parsing
+  // historical v1/v2 snapshots that predate the persisted field.
+  unit: z.string().trim().min(1).max(40).default('件'),
   required: z.boolean(),
   quantityRule: z.string().trim().min(1).max(1_000),
   dimensionRule: z.string().trim().min(1).max(2_000),
   materialScope: z.string().trim().max(1_000).default(''),
+  // Runtime inheritance is denied by default. Only a category Skill may mark
+  // a physical slot as part of its safe primary-material surface.
+  primaryMaterialSlot: z.boolean().default(false),
   evidenceFactIds: z.array(z.string().trim().min(1).max(160)).max(100).default([]),
   confidence: confidenceSchema,
   reviewFlags: z.array(z.string().trim().min(1).max(500)).max(20).default([]),
diff --git a/furniture-3d-system/src/server/services/bom-costing/bom-costing-processing.service.test.ts b/furniture-3d-system/src/server/services/bom-costing/bom-costing-processing.service.test.ts
index 6a05e5c4..ed7f126f 100644
--- a/furniture-3d-system/src/server/services/bom-costing/bom-costing-processing.service.test.ts
+++ b/furniture-3d-system/src/server/services/bom-costing/bom-costing-processing.service.test.ts
@@ -218,11 +218,11 @@ const supportedV3AnalysisResult = {
   schemaVersion: 'competitor-analysis/v3' as const,
   structureBlueprint: {
     schemaVersion: 'structure-blueprint/v2' as const,
-    knowledgeVersion: 'structure-priors/test-v2',
+    knowledgeVersion: 'structure-priors/2026-08-11-v2',
     supportStatus: 'SUPPORTED' as const,
     categorySkill: {
       selectedSkillId: 'TABLE',
-      selectedSkillVersion: 'bom-category-skill/table/test-v1',
+      selectedSkillVersion: 'bom-category-skill/table/v1',
       selectionMode: 'AUTO_SINGLE' as const,
       requiredEvidenceCoverage: 0.55,
       candidates: [],
@@ -234,14 +234,16 @@ const supportedV3AnalysisResult = {
       label: '桌台',
       skuIds: ['sku-1'],
       componentSlots: [{
-        componentKey: 'line-board',
+        componentKey: 'surface-main',
         role: 'SURFACE' as const,
         category: 'BOARD' as const,
         partName: '桌面板',
+        unit: '块',
         required: true,
         quantityRule: '每件一块',
         dimensionRule: '按 SKU 尺寸',
         materialScope: '主体材质',
+        primaryMaterialSlot: true,
         evidenceFactIds: [],
         confidence: 0.8,
         reviewFlags: [],
@@ -432,7 +434,7 @@ describe('BomCostingProcessingService', () => {
     jest.restoreAllMocks()
   })
 
-  it('成本阶段中断后复用已保存结构继续处理，并让同一 run 完成', async () => {
+  it('当前 v6 单位与主体材质合同的结构快照可继续成本恢复，并让同一 run 完成', async () => {
     jest.spyOn(bomCostingRepository, 'findProcessingAnalysisRun')
       .mockResolvedValue({
         id: 'analysis-run-recovered',
@@ -485,6 +487,102 @@ describe('BomCostingProcessingService', () => {
     expect(bomCostingRepository.failCase).not.toHaveBeenCalled()
   })
 
+  it('旧 v3 快照缺少 Skill 明确单位时拒绝成本快速恢复并重建结构', async () => {
+    const legacyV3WithoutSlotUnit = structuredClone(supportedV3AnalysisResult)
+    delete (
+      legacyV3WithoutSlotUnit.structureBlueprint.structureGroups[0]!
+        .componentSlots[0]! as Partial<{ unit: string }>
+    ).unit
+    jest.spyOn(bomCostingRepository, 'findProcessingAnalysisRun')
+      .mockResolvedValue({
+        id: 'analysis-run-legacy-unit-contract',
+        caseId: 'case-1',
+        revision: 2,
+        mode: BomCostingAnalysisRunMode.REUSE_FACTS,
+        status: BomCostingAnalysisRunStatus.PROCESSING,
+        factAnalysisId: 'fact-analysis-1',
+        selectedAssetIds: [],
+        instruction: '',
+        resultSnapshot: legacyV3WithoutSlotUnit,
+      } as never)
+    jest.spyOn(bomCostingRepository, 'findCaseForProcessing')
+      .mockResolvedValue({
+        ...caseRecord(),
+        progress: 97,
+        statusMessage: '已恢复后台任务，继续生成分层成本',
+        skus: [{ id: 'sku-db-1', externalSkuId: 'sku-1' }],
+      } as never)
+    mockRunAnalysis.mockRejectedValueOnce(
+      new Error('停止在旧结构快照重建后的测试边界'),
+    )
+    const { BomCostingProcessingService } = await import(
+      './bom-costing-processing.service'
+    )
+
+    await new BomCostingProcessingService().processCase('case-1')
+
+    expect(bomCostingScenarioService.calculateSameMaterialForCase)
+      .not.toHaveBeenCalled()
+    expect(bomCostingRepository.updateCaseStage).not.toHaveBeenCalledWith(
+      'case-1',
+      expect.objectContaining({ eventType: 'DYNAMIC_COST_RECOVERY_RESUMED' }),
+    )
+    expect(mockRunAnalysis).toHaveBeenCalledWith(
+      expect.objectContaining({
+        structureCheckpoint: null,
+        synthesisCheckpoint: null,
+      }),
+    )
+  })
+
+  it('旧 v3 快照缺少 Skill 主体材质槽声明时拒绝成本快速恢复并重建结构', async () => {
+    const legacyV3WithoutPrimaryMaterialContract = structuredClone(supportedV3AnalysisResult)
+    delete (
+      legacyV3WithoutPrimaryMaterialContract.structureBlueprint.structureGroups[0]!
+        .componentSlots[0]! as Partial<{ primaryMaterialSlot: boolean }>
+    ).primaryMaterialSlot
+    jest.spyOn(bomCostingRepository, 'findProcessingAnalysisRun')
+      .mockResolvedValue({
+        id: 'analysis-run-legacy-primary-material-contract',
+        caseId: 'case-1',
+        revision: 2,
+        mode: BomCostingAnalysisRunMode.REUSE_FACTS,
+        status: BomCostingAnalysisRunStatus.PROCESSING,
+        factAnalysisId: 'fact-analysis-1',
+        selectedAssetIds: [],
+        instruction: '',
+        resultSnapshot: legacyV3WithoutPrimaryMaterialContract,
+      } as never)
+    jest.spyOn(bomCostingRepository, 'findCaseForProcessing')
+      .mockResolvedValue({
+        ...caseRecord(),
+        progress: 97,
+        statusMessage: '已恢复后台任务，继续生成分层成本',
+        skus: [{ id: 'sku-db-1', externalSkuId: 'sku-1' }],
+      } as never)
+    mockRunAnalysis.mockRejectedValueOnce(
+      new Error('停止在旧主体材质槽合同重建后的测试边界'),
+    )
+    const { BomCostingProcessingService } = await import(
+      './bom-costing-processing.service'
+    )
+
+    await new BomCostingProcessingService().processCase('case-1')
+
+    expect(bomCostingScenarioService.calculateSameMaterialForCase)
+      .not.toHaveBeenCalled()
+    expect(bomCostingRepository.updateCaseStage).not.toHaveBeenCalledWith(
+      'case-1',
+      expect.objectContaining({ eventType: 'DYNAMIC_COST_RECOVERY_RESUMED' }),
+    )
+    expect(mockRunAnalysis).toHaveBeenCalledWith(
+      expect.objectContaining({
+        structureCheckpoint: null,
+        synthesisCheckpoint: null,
+      }),
+    )
+  })
+
   it('成本阶段恢复也不能绕过当前图片 fingerprint 门禁', async () => {
     jest.spyOn(bomCostingRepository, 'findProcessingAnalysisRun')
       .mockResolvedValue({
diff --git a/furniture-3d-system/src/server/services/bom-costing/bom-costing-processing.service.ts b/furniture-3d-system/src/server/services/bom-costing/bom-costing-processing.service.ts
index 6f1c88be..e37af3b1 100644
--- a/furniture-3d-system/src/server/services/bom-costing/bom-costing-processing.service.ts
+++ b/furniture-3d-system/src/server/services/bom-costing/bom-costing-processing.service.ts
@@ -41,6 +41,8 @@ import { prepareBomCostingAnalysis } from './bom-costing-result-preparer'
 import { assertBomCostingResultQuality } from './bom-costing-result-quality'
 import { bomCostingScenarioService } from './bom-costing-scenario.service'
 import { getCompetitorAnalysisProvider } from './bom-costing-provider'
+import { getBomCostingCategorySkill } from './category-skills'
+import { BOM_COSTING_STRUCTURE_KNOWLEDGE_VERSION } from './bom-costing-structure-knowledge'
 import {
   readBomCostingStructureCheckpoint,
   readBomCostingSynthesisCheckpoint,
@@ -205,6 +207,75 @@ function buildResultStats(
   }
 }
 
+function isRecord(value: unknown): value is Record<string, unknown> {
+  return typeof value === 'object' && value !== null && !Array.isArray(value)
+}
+
+/**
+ * Dynamic-cost recovery intentionally inspects the raw persisted JSON instead
+ * of the compatibility-parsed result. Historical v3 snapshots predate the
+ * Skill-owned slot unit and Zod fills their missing unit with "件" so they can
+ * still be displayed. That compatibility default must never authorize a new
+ * v7 cost calculation.
+ */
+function hasCurrentStructureUnitContract(value: unknown) {
+  if (!isRecord(value) || value.schemaVersion !== 'competitor-analysis/v3') {
+    return false
+  }
+  const blueprint = value.structureBlueprint
+  if (
+    !isRecord(blueprint) ||
+    blueprint.schemaVersion !== 'structure-blueprint/v2' ||
+    blueprint.knowledgeVersion !== BOM_COSTING_STRUCTURE_KNOWLEDGE_VERSION ||
+    blueprint.supportStatus !== 'SUPPORTED'
+  ) {
+    return false
+  }
+  const selection = blueprint.categorySkill
+  if (!isRecord(selection)) return false
+  const selectedSkillId = selection.selectedSkillId
+  const selectedSkillVersion = selection.selectedSkillVersion
+  if (
+    typeof selectedSkillId !== 'string' ||
+    typeof selectedSkillVersion !== 'string'
+  ) {
+    return false
+  }
+  const skill = getBomCostingCategorySkill(selectedSkillId)
+  if (!skill || skill.version !== selectedSkillVersion) return false
+
+  const contractByComponentKey = new Map(
+    [...skill.requiredComponents, ...skill.optionalComponents]
+      .map((component) => [component.componentKey, {
+        unit: component.unit,
+        primaryMaterialSlot: component.primaryMaterialSlot === true,
+      }] as const),
+  )
+  if (!Array.isArray(blueprint.structureGroups) || blueprint.structureGroups.length === 0) {
+    return false
+  }
+  return blueprint.structureGroups.every((group) => {
+    if (!isRecord(group) || !Array.isArray(group.componentSlots)) return false
+    return group.componentSlots.length > 0 && group.componentSlots.every((slot) => {
+      if (!isRecord(slot)) return false
+      const componentKey = slot.componentKey
+      const unit = slot.unit
+      const primaryMaterialSlot = slot.primaryMaterialSlot
+      const componentContract = typeof componentKey === 'string'
+        ? contractByComponentKey.get(componentKey)
+        : undefined
+      return (
+        typeof componentKey === 'string' &&
+        typeof unit === 'string' &&
+        unit.trim().length > 0 &&
+        typeof primaryMaterialSlot === 'boolean' &&
+        unit === componentContract?.unit &&
+        primaryMaterialSlot === componentContract.primaryMaterialSlot
+      )
+    })
+  })
+}
+
 async function completeDynamicCostingPhase(input: {
   caseId: string
   analysisRunId: string
@@ -622,6 +693,7 @@ export class BomCostingProcessingService {
       const savedSkuIds = record.skus.map((sku) => sku.externalSkuId).sort()
       const canResumeDynamicCosting =
         record.progress >= 97 &&
+        hasCurrentStructureUnitContract(analysisRun.resultSnapshot) &&
         persistedAnalysis.success &&
         persistedAnalysis.data.schemaVersion === 'competitor-analysis/v3' &&
         persistedAnalysis.data.structureBlueprint.supportStatus === 'SUPPORTED' &&
diff --git a/furniture-3d-system/src/server/services/bom-costing/bom-costing-production-27.integration.test.ts b/furniture-3d-system/src/server/services/bom-costing/bom-costing-production-27.integration.test.ts
index 8e57a7c5..7c493b97 100644
--- a/furniture-3d-system/src/server/services/bom-costing/bom-costing-production-27.integration.test.ts
+++ b/furniture-3d-system/src/server/services/bom-costing/bom-costing-production-27.integration.test.ts
@@ -276,7 +276,7 @@ async function runStructurePipeline(orderedFixture: readonly ProductionWardrobe2
   }
   const checkpoint = readBomCostingStructureCheckpoint({
     kind: 'BOM_COSTING_STRUCTURE_CHECKPOINT',
-    version: 4,
+    version: 6,
     sourceSkuIds: snapshot.skus.map((sku) => sku.externalSkuId),
     blueprint,
     completedGroupKeys: [],
@@ -442,6 +442,33 @@ describe('生产形态 27 SKU 衣柜全链回归', () => {
       expect(run.prepared.every((sku) => sku.estimatedCost === null)).toBe(true)
       assertBlueprintCoverage(run.blueprint)
       assertKnownDimensionSubsetQuality(run)
+
+      const slotsByGroup = new Map(run.blueprint.structureGroups.map((group) => [
+        group.structureGroupKey,
+        new Map(group.componentSlots.map((slot) => [slot.componentKey, slot] as const)),
+      ] as const))
+      for (const sku of run.output.result.skus) {
+        const groupSlots = slotsByGroup.get(sku.structureGroupKey!)!
+        const linesById = new Map(sku.bomLines.map((line) => [line.externalLineId, line] as const))
+        for (const line of sku.bomLines) {
+          expect(line.unit).toBe(groupSlots.get(line.externalLineId)?.unit)
+        }
+        for (const mainComponentKey of [
+          'enclosure-side',
+          'enclosure-top',
+          'enclosure-bottom',
+          'partition-vertical',
+          'partition-horizontal',
+          'cover-door',
+          'top-cabinet-side',
+          'top-cabinet-horizontal',
+        ]) {
+          const line = linesById.get(mainComponentKey)
+          if (line) expect(line.materialName).toBe('白蜡木')
+        }
+        expect(linesById.get('back-panel')?.materialName).toBeUndefined()
+        expect(linesById.get('drawer-box')?.materialName).toBeUndefined()
+      }
     }
     expect(fetchSpy).toHaveBeenCalledTimes(81)
 
diff --git a/furniture-3d-system/src/server/services/bom-costing/bom-costing-scenario.service.test.ts b/furniture-3d-system/src/server/services/bom-costing/bom-costing-scenario.service.test.ts
index 0ded994b..30ba27f6 100644
--- a/furniture-3d-system/src/server/services/bom-costing/bom-costing-scenario.service.test.ts
+++ b/furniture-3d-system/src/server/services/bom-costing/bom-costing-scenario.service.test.ts
@@ -2050,29 +2050,54 @@ describe('BomCostingScenarioService', () => {
     })
   })
 
-  it('板材存在应计但缺面尺寸的行时不按残余面积缩放成完整成本', async () => {
+  it('部分板材缺面尺寸时不按部分面积缩放整套总额，只用未缩放正残差补缺价行', async () => {
     const bomLines = [
       line({
         id: 'complete-panel',
         category: 'BOARD',
         partName: '已知尺寸板件',
+        materialName: '橡胶木',
         unit: '块',
         quantity: 1,
         lengthMm: 2_000,
         widthMm: 500,
       }),
+      line({
+        id: 'complete-unpriced-panel',
+        category: 'BOARD',
+        partName: '有尺寸缺价板件',
+        materialName: '橡胶木',
+        unit: '块',
+        quantity: 3,
+        lengthMm: 1_000,
+        widthMm: 500,
+      }),
       line({
         id: 'missing-depth-panel',
         category: 'BOARD',
         partName: '缺深度板件',
+        materialName: '橡胶木',
         unit: '块',
-        quantity: 2,
+        quantity: 1,
         lengthMm: 2_000,
         widthMm: null,
       }),
     ]
     mockBase({ bomLines })
-    jest.spyOn(bomCostingScenarioRepository, 'findReferenceCandidates').mockResolvedValue([])
+    jest.spyOn(bomCostingScenarioRepository, 'findReferenceCandidates').mockImplementation(
+      async (input) => input.partName === '已知尺寸板件'
+        ? [candidate({
+            id: 'priced-complete-panel',
+            category: 'BOARD',
+            partName: '已知尺寸板件',
+            materialName: '橡胶木',
+            unit: '块',
+            unitPrice: 40,
+            lengthMm: 2_000,
+            widthMm: 500,
+          })]
+        : [],
+    )
     jest.spyOn(bomCostingScenarioRepository, 'findCategoryCohortCandidates').mockImplementation(
       async (input) => input.category === 'BOARD'
         ? [
@@ -2092,24 +2117,103 @@ describe('BomCostingScenarioService', () => {
       bomCostingScenarioRepository.saveSameMaterialScenario,
     ).mock.calls[0]![0]
     expect(saved.sameMaterial).toMatchObject({
-      status: 'INSUFFICIENT_DATA',
-      total: null,
-      knownCost: 0,
-      unresolvedCount: 2,
+      status: 'PROVISIONAL',
+      total: 100,
+      knownCost: 100,
+      unresolvedCount: 0,
+      warning: expect.stringContaining('部分板材面尺寸缺失'),
+    })
+    const byLine = new Map(saved.sameMaterial.lines.map((item) => [item.sourceLineId, item]))
+    expect(byLine.get('complete-panel')).toMatchObject({
+      subtotal: 40,
+      unitPrice: 40,
+    })
+    expect(byLine.get('complete-unpriced-panel')).toMatchObject({
+      subtotal: 45,
+      status: 'PROVISIONAL',
+      confidence: 0.38,
+      calculationRule: 'reference-profile-category-gap-allocation/v3-partial-unscaled',
+      rawSnapshot: {
+        calculation: {
+          priceSourceAudit: expect.objectContaining({
+            allocatedShare: 0.75,
+          }),
+        },
+      },
+    })
+    expect(byLine.get('missing-depth-panel')).toMatchObject({
+      subtotal: 15,
+      status: 'PROVISIONAL',
+      confidence: 0.38,
+      calculationRule: 'reference-profile-category-gap-allocation/v3-partial-unscaled',
+      warning: expect.stringContaining('部分板材面尺寸缺失'),
+      rawSnapshot: {
+        calculation: {
+          priceSourceAudit: expect.objectContaining({
+            historicalMedianCategoryTotal: 100,
+            currentPhysicalQuantity: 2.5,
+            areaScaleApplied: false,
+            unscaledBoardFallbackReason: 'PARTIAL_FACE_DIMENSIONS',
+            partialPhysicalQuantityExcludedFromScale: true,
+            appliedPhysicalScale: 1,
+            alreadyPricedCategoryCost: 40,
+            remainingCategoryEstimate: 60,
+            existingPricesPreserved: true,
+            allocatedShare: 0.25,
+          }),
+        },
+      },
     })
-    expect(saved.sameMaterial.lines).toEqual(expect.arrayContaining([
-      expect.objectContaining({ sourceLineId: 'complete-panel', subtotal: null }),
-      expect.objectContaining({ sourceLineId: 'missing-depth-panel', subtotal: null }),
-    ]))
-    expect(saved.sameMaterial.lines).not.toEqual(expect.arrayContaining([
-      expect.objectContaining({
-        calculationRule: 'reference-profile-category-gap-allocation/v2-area-scaled',
-      }),
-    ]))
     expect(
       jest.mocked(bomCostingScenarioRepository.findCategoryCohortCandidates)
         .mock.calls.filter(([input]) => input.category === 'BOARD'),
-    ).toHaveLength(0)
+    ).not.toHaveLength(0)
+  })
+
+  it('部分板材缺面尺寸且没有完整历史 BOM 时不退回逐行宽泛估价', async () => {
+    const bomLines = [
+      line({
+        id: 'complete-panel',
+        category: 'BOARD',
+        partName: '已知尺寸板件',
+        materialName: '橡胶木',
+        unit: '块',
+        quantity: 1,
+        lengthMm: 2_000,
+        widthMm: 500,
+      }),
+      line({
+        id: 'missing-depth-panel',
+        category: 'BOARD',
+        partName: '缺深度板件',
+        materialName: '橡胶木',
+        unit: '块',
+        quantity: 1,
+        lengthMm: 2_000,
+        widthMm: null,
+      }),
+    ]
+    mockBase({ bomLines })
+    jest.spyOn(bomCostingScenarioRepository, 'findReferenceCandidates').mockResolvedValue([])
+    jest.spyOn(bomCostingScenarioRepository, 'findCategoryCohortCandidates').mockResolvedValue([])
+
+    await new BomCostingScenarioService().calculateSameMaterial({
+      caseId: 'case-1',
+      skuId: 'sku-1',
+    })
+
+    const saved = jest.mocked(
+      bomCostingScenarioRepository.saveSameMaterialScenario,
+    ).mock.calls[0]![0]
+    expect(saved.sameMaterial).toMatchObject({
+      status: 'INSUFFICIENT_DATA',
+      total: null,
+      unresolvedCount: 2,
+    })
+    expect(
+      jest.mocked(bomCostingScenarioRepository.findCategoryCohortCandidates)
+        .mock.calls.filter(([input]) => input.category === 'BOARD'),
+    ).toHaveLength(1)
   })
 
   it('板材面尺寸全部缺失时使用低可信的整套历史未缩放预估', async () => {
diff --git a/furniture-3d-system/src/server/services/bom-costing/bom-costing-scenario.service.ts b/furniture-3d-system/src/server/services/bom-costing/bom-costing-scenario.service.ts
index b809510f..1835a3d6 100644
--- a/furniture-3d-system/src/server/services/bom-costing/bom-costing-scenario.service.ts
+++ b/furniture-3d-system/src/server/services/bom-costing/bom-costing-scenario.service.ts
@@ -1760,29 +1760,29 @@ async function fillCategoryProfileFallbacks(input: {
     const boardCoverage = category === 'BOARD'
       ? boardFaceDimensionCoverage(categoryLines)
       : null
-    if (
-      category === 'BOARD' &&
+    const partialBoardDimensionFallback = category === 'BOARD' &&
       boardCoverage !== null &&
       boardCoverage.completeFaceCount > 0 &&
       boardCoverage.incompleteFaceCount > 0
-    ) {
-      // A partial board-area sum is not the physical quantity of the whole
-      // product. Do not scale a complete historical BOARD total by only the
-      // surviving dimensions, and prevent the later per-line cohort fallback
-      // from turning those unknown cuts into a falsely complete scenario.
-      for (const line of missingLines) handledLineIds.add(line.id)
-      continue
-    }
     const estimate = await resolveCategoryProfileEstimate({
       syncRunId: input.syncRunId,
       category,
       familyReferenceSkus: input.familyReferenceSkus,
       similarReferenceSkus: input.similarReferenceSkus,
     })
-    if (!estimate) continue
+    if (!estimate) {
+      // Partial BOARD dimensions may only be completed from a whole-BOM
+      // category profile. A later per-line cohort quote would bypass that
+      // safety boundary and make an incomplete structure appear complete.
+      if (partialBoardDimensionFallback) {
+        for (const line of missingLines) handledLineIds.add(line.id)
+      }
+      continue
+    }
     for (const line of missingLines) handledLineIds.add(line.id)
     const currentPhysicalQuantity = currentCategoryPhysicalQuantity(category, categoryLines)
     const areaScaleApplied = (
+      !partialBoardDimensionFallback &&
       currentPhysicalQuantity !== null &&
       estimate.medianPhysicalQuantity !== null &&
       estimate.medianPhysicalQuantity > 0
@@ -1794,16 +1794,24 @@ async function fillCategoryProfileFallbacks(input: {
     // scaling while limiting incomplete structures or extreme source records
     // from multiplying a whole category without bound.
     const physicalScale = Math.min(3, Math.max(0.35, rawPhysicalScale))
-    const unscaledBoardFallback = category === 'BOARD' && (
+    const allBoardDimensionsMissingFallback = category === 'BOARD' && (
       boardCoverage?.billableCount ?? 0
     ) > 0 && boardCoverage?.completeFaceCount === 0
-    if (unscaledBoardFallback) {
+    const unscaledBoardFallback = partialBoardDimensionFallback || allBoardDimensionsMissingFallback
+    if (allBoardDimensionsMissingFallback) {
       warnings.push({
         category,
         lineIds: missingLines.map((line) => line.id),
         warning: '全部板材面尺寸缺失，当前按相似整套历史 BOM 中位数进行未缩放预估；该结果可信度较低，需补充板件尺寸后复核',
       })
     }
+    if (partialBoardDimensionFallback) {
+      warnings.push({
+        category,
+        lineIds: missingLines.map((line) => line.id),
+        warning: '部分板材面尺寸缺失，未使用已知板件的部分面积缩放整套历史 BOM；当前按相似整套历史 BOM 分类中位数进行未缩放预估，并仅将高于已定价成本的正残差分配给缺价行，需补充缺失尺寸后复核',
+      })
+    }
     const estimatedCategoryTotal = estimate.total * physicalScale
     const estimatedCategoryRange = {
       min: estimate.estimateRange.min * physicalScale,
@@ -1840,9 +1848,16 @@ async function fillCategoryProfileFallbacks(input: {
       min: Math.max(0, Math.min(remainingTotal, estimatedCategoryRange.min - knownCost)),
       max: Math.max(remainingTotal, estimatedCategoryRange.max - knownCost),
     }
-    const weights = missingLines.map((line) => (
-      categoryLineAllocationWeight(category, line)
-    ))
+    const weights = missingLines.map((line) => {
+      if (partialBoardDimensionFallback) {
+        // Some missing rows have an area and some do not. Mixing square metres
+        // and piece counts in one allocation denominator would distort the
+        // category residual, so this low-confidence path uses pieces only.
+        const quantity = decimalNumber(line.quantity)
+        return quantity !== null && quantity > 0 ? quantity : 1
+      }
+      return categoryLineAllocationWeight(category, line)
+    })
     const totalWeight = weights.reduce((sum, weight) => sum + weight, 0)
     missingLines.forEach((line, index) => {
       const share = weights[index]! / totalWeight
@@ -1851,7 +1866,7 @@ async function fillCategoryProfileFallbacks(input: {
         totalAmount: allocated,
         sourceType: 'LOCAL_MIRROR',
         sourceId: estimate.sourceId,
-        sourceLabel: `${estimate.basis === 'SKU_FAMILY' ? '同款 SKU' : estimate.basis === 'SIMILAR_HISTORY' ? '相似产品' : '同分类'}整套历史 BOM 分类总额补齐（${estimate.sampleCount} 套${areaScaleApplied ? '，按当前板件面积缩放' : unscaledBoardFallback ? '，当前板件尺寸全缺、未缩放' : ''}）`,
+        sourceLabel: `${estimate.basis === 'SKU_FAMILY' ? '同款 SKU' : estimate.basis === 'SIMILAR_HISTORY' ? '相似产品' : '同分类'}整套历史 BOM 分类总额补齐（${estimate.sampleCount} 套${areaScaleApplied ? '，按当前板件面积缩放' : partialBoardDimensionFallback ? '，部分板件尺寸缺失、未缩放' : allBoardDimensionsMissingFallback ? '，当前板件尺寸全缺、未缩放' : ''}）`,
         materialName: line.materialName,
         referenceSku: estimate.referenceSkus[0] ?? '',
         confidence: unscaledBoardFallback
@@ -1870,7 +1885,9 @@ async function fillCategoryProfileFallbacks(input: {
         sourceSyncedAt: estimate.sourceSyncedAt,
         calculationRule: areaScaleApplied
           ? 'reference-profile-category-gap-allocation/v2-area-scaled'
-          : unscaledBoardFallback
+          : partialBoardDimensionFallback
+            ? 'reference-profile-category-gap-allocation/v3-partial-unscaled'
+          : allBoardDimensionsMissingFallback
             ? 'reference-profile-category-gap-allocation/v2-unscaled'
           : 'reference-profile-category-gap-allocation/v1',
         referenceRowIds: estimate.referenceRowIds,
@@ -1897,6 +1914,12 @@ async function fillCategoryProfileFallbacks(input: {
           currentPhysicalQuantity,
           physicalUnit: estimate.physicalUnit,
           areaScaleApplied,
+          unscaledBoardFallbackReason: partialBoardDimensionFallback
+            ? 'PARTIAL_FACE_DIMENSIONS'
+            : allBoardDimensionsMissingFallback
+              ? 'ALL_FACE_DIMENSIONS_MISSING'
+              : null,
+          partialPhysicalQuantityExcludedFromScale: partialBoardDimensionFallback,
           boardFaceDimensionCoverage: boardCoverage,
           rawPhysicalScale,
           appliedPhysicalScale: physicalScale,
diff --git a/furniture-3d-system/src/server/services/bom-costing/bom-costing-structure-blueprint.test.ts b/furniture-3d-system/src/server/services/bom-costing/bom-costing-structure-blueprint.test.ts
index 050e0311..140f6ae7 100644
--- a/furniture-3d-system/src/server/services/bom-costing/bom-costing-structure-blueprint.test.ts
+++ b/furniture-3d-system/src/server/services/bom-costing/bom-costing-structure-blueprint.test.ts
@@ -195,7 +195,7 @@ describe('BOM v7 结构蓝图与 SKU 展开', () => {
     },
   )
 
-  it('当前 v4/v2 检查点可恢复，旧分组策略 v3 检查点失效', async () => {
+  it('当前 v6/v2 检查点可恢复，旧主体材质槽合同 v5 检查点失效', async () => {
     const snapshot = snapshotWithSkus(1)
     const factSnapshot = {
       schemaVersion: BOM_COSTING_FACT_SCHEMA_VERSION,
@@ -218,7 +218,7 @@ describe('BOM v7 结构蓝图与 SKU 展开', () => {
     const group = blueprint.structureGroups[0]!
     const checkpointValue = {
       kind: 'BOM_COSTING_STRUCTURE_CHECKPOINT',
-      version: 4,
+      version: 6,
       sourceSkuIds: ['sku-1'],
       blueprint,
       completedGroupKeys: [group.structureGroupKey],
@@ -242,7 +242,7 @@ describe('BOM v7 结构蓝图与 SKU 展开', () => {
     }
     expect(readBomCostingStructureCheckpoint({
       ...checkpointValue,
-      version: 3,
+      version: 5,
     })).toBeNull()
     const checkpoint = readBomCostingStructureCheckpoint(checkpointValue)
     expect(checkpoint).not.toBeNull()
@@ -289,7 +289,7 @@ describe('BOM v7 结构蓝图与 SKU 展开', () => {
     )
     const checkpoint = readBomCostingStructureCheckpoint({
       kind: 'BOM_COSTING_STRUCTURE_CHECKPOINT',
-      version: 4,
+      version: 6,
       sourceSkuIds: snapshot.skus.map((sku) => sku.externalSkuId),
       blueprint,
       completedGroupKeys: blueprint.structureGroups.map((group) => group.structureGroupKey),
@@ -634,7 +634,7 @@ describe('BOM v7 结构蓝图与 SKU 展开', () => {
     expect(boardArea(1)).toBeGreaterThan(boardArea(0))
   })
 
-  it('同一 SKU 的主体白蜡木和松木背板仅绑定各自有证据的槽位', async () => {
+  it('同一 SKU 的主体白蜡木可安全继承，松木背板仍优先使用槽位专属事实', async () => {
     const snapshot = snapshotWithSkus(1)
     snapshot.title = '白蜡木主体搭配松木背板实木衣柜'
     snapshot.skus[0]!.name = '白蜡木主体+松木辅材推拉门衣柜'
@@ -706,7 +706,7 @@ describe('BOM v7 结构蓝图与 SKU 展开', () => {
     const byId = new Map(output.result.skus[0]!.bomLines.map((line) => [line.externalLineId, line]))
     expect(byId.get('enclosure-side')?.materialName).toBe('白蜡木')
     expect(byId.get('back-panel')?.materialName).toBe('松木')
-    expect(byId.get('enclosure-top')?.materialName).toBeUndefined()
+    expect(byId.get('enclosure-top')?.materialName).toBe('白蜡木')
     expect(byId.get('processing-main')?.materialName).toBeUndefined()
     expect(byId.get('processing-main')?.processName).toBeUndefined()
     expect(byId.get('labor-assembly')?.materialName).toBeUndefined()
@@ -776,6 +776,250 @@ describe('BOM v7 结构蓝图与 SKU 展开', () => {
       .every((line) => line.materialName === undefined)).toBe(true)
   })
 
+  it('主体槽位自身包含多材质冲突时不使用成本组主体材质覆盖', async () => {
+    const snapshot = snapshotWithSkus(1)
+    snapshot.title = '白蜡木实木衣柜'
+    snapshot.skus[0]!.name = '白蜡木推拉门衣柜'
+    const factSnapshot = {
+      schemaVersion: BOM_COSTING_FACT_SCHEMA_VERSION,
+      imageFacts: [{
+        imageId: 'conflicting-side-material',
+        sourceImageUrl: 'https://img.example.com/conflicting-side-material.jpg',
+        kind: 'DETAIL' as const,
+        label: '侧板材质说明',
+        externalSkuIds: ['sku-1'],
+        observedTexts: [],
+        facts: [{
+          factId: 'fact-conflicting-side-material',
+          kind: 'MATERIAL' as const,
+          subject: '柜体侧板',
+          value: '白蜡木与松木拼接',
+          relatedSkuIds: ['sku-1'],
+          basis: 'SOURCE_TEXT' as const,
+          confidence: 0.95,
+        }],
+      }],
+      failedImages: [],
+      extractedAt: new Date().toISOString(),
+    }
+    jest.spyOn(global, 'fetch').mockImplementation(async (_url, init) => {
+      const body = JSON.parse(String(init?.body)) as {
+        messages: Array<{ content: string | Array<{ type: string; text?: string }> }>
+      }
+      const content = body.messages[1]?.content ?? '{}'
+      const text = typeof content === 'string'
+        ? content
+        : content.find((entry) => entry.type === 'text')?.text ?? '{}'
+      const payload = JSON.parse(text) as {
+        sku?: Array<[string, string, string, Record<string, unknown>]>
+        slots?: Array<[string, string, string]>
+      }
+      return streamingResponse(JSON.stringify({
+        skus: (payload.sku ?? []).map((sku) => ({
+          sku: sku[0],
+          d: [1_400, 620, 2_200],
+          lines: (payload.slots ?? []).map((slot) => ([
+            slot[0], 1, slot[2] === 'BOARD' ? '块' : '套',
+            null, null, null, null, [],
+          ])),
+        })),
+      }))
+    })
+
+    const output = await buildStructuredBomCostingAnalysis({
+      config,
+      sourceUrl: snapshot.detailUrl,
+      snapshot,
+      factSnapshot,
+      requestedCategorySkillId: 'WARDROBE',
+    })
+    expect(output.result.skus[0]?.bomLines.find(
+      (line) => line.externalLineId === 'enclosure-side',
+    )?.materialName).toBeUndefined()
+  })
+
+  it('生产形态的唯一主体材质可安全继承，且模型 mm 单位不能覆盖 Skill 计数单位', async () => {
+    const snapshot = snapshotWithSkus(1)
+    snapshot.title = '现代简约白蜡木推拉门实木衣柜'
+    snapshot.skus[0]!.name = '1.4米宽 白蜡木柜体 推拉门衣柜'
+    snapshot.skus[0]!.attributes = { 尺寸: '140cm', 材质: '白蜡木' }
+    const factSnapshot = {
+      schemaVersion: BOM_COSTING_FACT_SCHEMA_VERSION,
+      imageFacts: [{
+        imageId: 'generic-primary-material',
+        sourceImageUrl: 'https://img.example.com/generic-primary-material.jpg',
+        kind: 'DETAIL' as const,
+        label: '主体材质说明',
+        externalSkuIds: ['sku-1'],
+        observedTexts: [],
+        facts: [{
+          factId: 'fact-primary-white-ash',
+          kind: 'MATERIAL' as const,
+          subject: '柜体主体材质',
+          value: '白蜡木',
+          relatedSkuIds: ['sku-1'],
+          basis: 'SOURCE_TEXT' as const,
+          confidence: 0.98,
+        }],
+      }],
+      failedImages: [],
+      extractedAt: new Date().toISOString(),
+    }
+    jest.spyOn(global, 'fetch').mockImplementation(async (_url, init) => {
+      const body = JSON.parse(String(init?.body)) as {
+        messages: Array<{ content: string | Array<{ type: string; text?: string }> }>
+      }
+      const content = body.messages[1]?.content ?? '{}'
+      const text = typeof content === 'string'
+        ? content
+        : content.find((entry) => entry.type === 'text')?.text ?? '{}'
+      const payload = JSON.parse(text) as {
+        sku?: Array<[string, string, string, Record<string, unknown>]>
+        slots?: Array<[string, string, string]>
+      }
+      return streamingResponse(JSON.stringify({
+        skus: (payload.sku ?? []).map((sku) => ({
+          sku: sku[0],
+          d: [1_400, 620, 2_200],
+          lines: (payload.slots ?? []).map((slot) => ([
+            slot[0], 1, 'mm', null, null, null,
+            slot[2] === 'BOARD' ? '白蜡木' : null,
+            slot[2] === 'BOARD' ? ['fact-primary-white-ash'] : [],
+          ])),
+        })),
+      }))
+    })
+
+    const output = await buildStructuredBomCostingAnalysis({
+      config,
+      sourceUrl: snapshot.detailUrl,
+      snapshot,
+      factSnapshot,
+      requestedCategorySkillId: 'WARDROBE',
+    })
+    const skuResult = output.result.skus[0]!
+    const byId = new Map(skuResult.bomLines.map((line) => [line.externalLineId, line]))
+    for (const componentKey of [
+      'enclosure-side',
+      'enclosure-top',
+      'enclosure-bottom',
+      'partition-vertical',
+      'partition-horizontal',
+      'cover-door',
+    ]) {
+      expect(byId.get(componentKey)).toMatchObject({ materialName: '白蜡木', unit: '块' })
+    }
+    expect(byId.get('back-panel')).toMatchObject({ unit: '块' })
+    expect(byId.get('back-panel')?.materialName).toBeUndefined()
+    expect(byId.get('processing-main')?.unit).toBe('套')
+    expect(skuResult.bomLines.some((line) => line.unit === 'mm')).toBe(false)
+  })
+
+  it.each([
+    {
+      skillId: 'TABLE',
+      title: '白蜡木桌面碳钢桌腿餐桌',
+      supportSubject: '碳钢桌腿',
+      primaryKey: 'surface-main',
+      supportKey: 'support-leg',
+      isolatedKey: 'support-apron',
+    },
+    {
+      skillId: 'HARD_SEATING',
+      title: '白蜡木座面碳钢椅腿餐椅',
+      supportSubject: '碳钢椅腿',
+      primaryKey: 'surface-seat',
+      supportKey: 'support-seat',
+      isolatedKey: 'support-seat-brace',
+    },
+    {
+      skillId: 'STORAGE_RACK',
+      title: '白蜡木层板碳钢立柱置物架',
+      supportSubject: '碳钢立柱',
+      primaryKey: 'partition-shelf',
+      supportKey: 'support-upright',
+      isolatedKey: 'support-cross-brace',
+    },
+  ])(
+    '$skillId 混合材质仅向 Skill 明确声明的主体槽继承',
+    async ({ skillId, title, supportSubject, primaryKey, supportKey, isolatedKey }) => {
+      const snapshot = snapshotWithSkus(1)
+      snapshot.itemId = `mixed-${skillId.toLocaleLowerCase()}`
+      snapshot.title = title
+      snapshot.skus[0]!.name = title
+      snapshot.skus[0]!.attributes = { 材质: '白蜡木+碳钢' }
+      const factSnapshot = {
+        schemaVersion: BOM_COSTING_FACT_SCHEMA_VERSION,
+        imageFacts: [{
+          imageId: `mixed-material-${skillId}`,
+          sourceImageUrl: `https://img.example.com/mixed-material-${skillId}.jpg`,
+          kind: 'DETAIL' as const,
+          label: '混合材质说明',
+          externalSkuIds: ['sku-1'],
+          observedTexts: [],
+          facts: [{
+            factId: `fact-primary-${skillId}`,
+            kind: 'MATERIAL' as const,
+            subject: '产品主体材质',
+            value: '白蜡木',
+            relatedSkuIds: ['sku-1'],
+            basis: 'SOURCE_TEXT' as const,
+            confidence: 0.98,
+          }, {
+            factId: `fact-support-${skillId}`,
+            kind: 'MATERIAL' as const,
+            subject: supportSubject,
+            value: '碳钢',
+            relatedSkuIds: ['sku-1'],
+            basis: 'SOURCE_TEXT' as const,
+            confidence: 0.98,
+          }],
+        }],
+        failedImages: [],
+        extractedAt: new Date().toISOString(),
+      }
+      jest.spyOn(global, 'fetch').mockImplementation(async (_url, init) => {
+        const body = JSON.parse(String(init?.body)) as {
+          messages: Array<{ content: string | Array<{ type: string; text?: string }> }>
+        }
+        const content = body.messages[1]?.content ?? '{}'
+        const text = typeof content === 'string'
+          ? content
+          : content.find((entry) => entry.type === 'text')?.text ?? '{}'
+        const payload = JSON.parse(text) as {
+          sku?: Array<[string, string, string, Record<string, unknown>]>
+          slots?: Array<[string, string, string]>
+        }
+        return streamingResponse(JSON.stringify({
+          skus: (payload.sku ?? []).map((sku) => ({
+            sku: sku[0],
+            d: [1_200, 600, 750],
+            lines: (payload.slots ?? []).map((slot) => ([
+              slot[0], 1, '件', null, null, null, null, [],
+            ])),
+          })),
+        }))
+      })
+
+      const output = await buildStructuredBomCostingAnalysis({
+        config,
+        sourceUrl: snapshot.detailUrl,
+        snapshot,
+        factSnapshot,
+        requestedCategorySkillId: skillId,
+      })
+      const group = output.result.structureBlueprint.structureGroups[0]!
+      const slotByKey = new Map(group.componentSlots.map((slot) => [slot.componentKey, slot]))
+      expect(slotByKey.get(primaryKey)?.primaryMaterialSlot).toBe(true)
+      expect(slotByKey.get(supportKey)?.primaryMaterialSlot).toBe(false)
+      expect(slotByKey.get(isolatedKey)?.primaryMaterialSlot).toBe(false)
+      const byId = new Map(output.result.skus[0]!.bomLines.map((line) => [line.externalLineId, line]))
+      expect(byId.get(primaryKey)?.materialName).toBe('白蜡木')
+      expect(byId.get(supportKey)?.materialName).toBe('碳钢')
+      expect(byId.get(isolatedKey)?.materialName).toBeUndefined()
+    },
+  )
+
   it('没有当前槽位 MATERIAL 事实时丢弃模型猜测的板材材质', async () => {
     const snapshot = snapshotWithSkus(1)
     jest.spyOn(global, 'fetch').mockImplementation(async (_url, init) => {
diff --git a/furniture-3d-system/src/server/services/bom-costing/bom-costing-structure-blueprint.ts b/furniture-3d-system/src/server/services/bom-costing/bom-costing-structure-blueprint.ts
index ac8641e0..e60853c4 100644
--- a/furniture-3d-system/src/server/services/bom-costing/bom-costing-structure-blueprint.ts
+++ b/furniture-3d-system/src/server/services/bom-costing/bom-costing-structure-blueprint.ts
@@ -140,9 +140,10 @@ const instantiationPayloadSchema = z.object({
 
 const BOM_COSTING_STRUCTURE_CHECKPOINT_KIND =
   'BOM_COSTING_STRUCTURE_CHECKPOINT' as const
-// Version 4 invalidates blueprints created before SKU-local category grouping.
-// Those checkpoints can contain product-wide variant signals on every SKU.
-const BOM_COSTING_STRUCTURE_CHECKPOINT_VERSION = 4 as const
+// Version 6 invalidates checkpoints created before the explicit
+// primaryMaterialSlot contract. Parsing a v5 checkpoint with the safe default
+// would otherwise suppress legitimate primary-material inheritance.
+const BOM_COSTING_STRUCTURE_CHECKPOINT_VERSION = 6 as const
 
 const bomCostingStructureCheckpointSchema = z.object({
   kind: z.literal(BOM_COSTING_STRUCTURE_CHECKPOINT_KIND),
@@ -825,42 +826,112 @@ function materialFamilyFromDescriptor(descriptor: string) {
   return families.length === 1 ? families[0] : undefined
 }
 
+function selectSingleMaterialDescriptor(descriptors: readonly string[]) {
+  const byFamily = new Map<string, string>()
+  for (const descriptor of descriptors) {
+    const family = materialFamilyFromDescriptor(descriptor)
+    if (!family) continue
+    const existing = byFamily.get(family)
+    if (!existing || descriptor.length > existing.length) {
+      byFamily.set(family, descriptor)
+    }
+  }
+  // “实木” is only a broad class. A single named timber plus “实木” is
+  // not a conflict, while two named timbers must never be spread to slots.
+  if (byFamily.size > 1 && byFamily.has('SOLID_WOOD')) {
+    byFamily.delete('SOLID_WOOD')
+  }
+  return byFamily.size === 1 ? Array.from(byFamily.values())[0] : undefined
+}
+
+function canInheritPrimaryMaterial(
+  slot: BomCostingStructureBlueprintV2['structureGroups'][number]['componentSlots'][number],
+) {
+  return slot.primaryMaterialSlot === true
+}
+
+function hasUnresolvedPrimaryMaterialConflict(input: {
+  primaryDescriptor: string
+  materialRecords: ReturnType<typeof listBomCostingFactRecords>
+  slots: BomCostingStructureBlueprintV2['structureGroups'][number]['componentSlots']
+}) {
+  const primaryFamily = materialFamilyFromDescriptor(input.primaryDescriptor)
+  if (!primaryFamily) return true
+  return input.materialRecords.some((record) => {
+    const context = `${record.fact.subject} ${record.fact.value} ${record.fact.note ?? ''}`
+    const families: string[] = Array.from(new Set(materialDescriptorsFromText(context)
+      .flatMap((descriptor) => materialFamilyFromDescriptor(descriptor) ?? [])
+      .filter((family) => family !== 'SOLID_WOOD')))
+    const otherFamilies = families.filter((family) => family !== primaryFamily)
+    if (otherFamilies.length === 0) return false
+    // A single broad fact containing multiple named materials is ambiguous.
+    if (families.includes(primaryFamily)) return true
+    // A different material explicitly bound by the blueprint to one or more
+    // non-primary slots (for example a steel table leg or pine back panel) is
+    // not a conflict for the Skill's primary-material slots. The decision is
+    // based on the Skill-owned slot contract, never on a part-name regex.
+    const boundSlots = input.slots.filter((slot) => slot.evidenceFactIds.includes(record.factId))
+    return boundSlots.length === 0 || boundSlots.some((slot) => slot.primaryMaterialSlot)
+  })
+}
+
 function resolvePhysicalMaterialDescriptor(input: {
   slot: BomCostingStructureBlueprintV2['structureGroups'][number]['componentSlots'][number]
   sku: MarketSkuSnapshot
   factSnapshot: BomCostingSourceFactSnapshot
   modelLine?: z.infer<typeof compactInstantiatedBomLineSchema>
+  primaryMaterialDescriptor?: string
+  groupSlots: BomCostingStructureBlueprintV2['structureGroups'][number]['componentSlots']
 }) {
   if (!['BOARD', 'STEEL', 'ACCESSORY'].includes(input.slot.category)) return undefined
   const allowedIds = new Set(input.slot.evidenceFactIds)
-  if (allowedIds.size === 0) return undefined
-  const records = listBomCostingFactRecords(input.factSnapshot).filter((record) => (
-    allowedIds.has(record.factId) &&
-    record.fact.kind === 'MATERIAL' &&
-    factAppliesToSku(record, input.sku.externalSkuId)
+  const allMaterialRecords = listBomCostingFactRecords(input.factSnapshot).filter((record) => (
+    record.fact.kind === 'MATERIAL' && factAppliesToSku(record, input.sku.externalSkuId)
   ))
-  const slotDescriptors = Array.from(new Set(records.flatMap((record) => (
+  const records = allMaterialRecords.filter((record) => allowedIds.has(record.factId))
+  const rawSlotDescriptors = records.flatMap((record) => (
     materialDescriptorsFromText(`${record.fact.subject} ${record.fact.value} ${record.fact.note ?? ''}`)
-  ))))
+  ))
+  const slotDescriptor = selectSingleMaterialDescriptor(rawSlotDescriptors)
   // Applicable slot facts outrank the model. This is what keeps a pine back
   // panel pine even when the model copies the ash carcass material onto it.
-  if (slotDescriptors.length === 1) return slotDescriptors[0]
-  if (slotDescriptors.length > 1) return undefined
+  if (slotDescriptor) return slotDescriptor
+  if (rawSlotDescriptors.length > 0) return undefined
 
   const modelDescriptor = input.modelLine?.descriptor?.trim()
   const modelFamily = modelDescriptor ? materialFamilyFromDescriptor(modelDescriptor) : undefined
-  if (!modelDescriptor || !modelFamily) return undefined
-  const referencedFactIds = new Set(input.modelLine?.evidenceFactIds ?? [])
-  const supportedDescriptors = Array.from(new Set(records
-    .filter((record) => referencedFactIds.has(record.factId))
-    .flatMap((record) => materialDescriptorsFromText(
-      `${record.fact.subject} ${record.fact.value} ${record.fact.note ?? ''}`,
-    ))))
-  const supportedFamilies = Array.from(new Set(
-    supportedDescriptors.flatMap((descriptor) => materialFamilyFromDescriptor(descriptor) ?? []),
+  if (modelDescriptor && modelFamily) {
+    const referencedFactIds = new Set(input.modelLine?.evidenceFactIds ?? [])
+    const supportedDescriptor = selectSingleMaterialDescriptor(records
+      .filter((record) => referencedFactIds.has(record.factId))
+      .flatMap((record) => materialDescriptorsFromText(
+        `${record.fact.subject} ${record.fact.value} ${record.fact.note ?? ''}`,
+      )))
+    if (
+      supportedDescriptor &&
+      materialFamilyFromDescriptor(supportedDescriptor) === modelFamily
+    ) {
+      return supportedDescriptor
+    }
+  }
+
+  if (!canInheritPrimaryMaterial(input.slot)) return undefined
+  if (
+    input.primaryMaterialDescriptor &&
+    !hasUnresolvedPrimaryMaterialConflict({
+      primaryDescriptor: input.primaryMaterialDescriptor,
+      materialRecords: allMaterialRecords,
+      slots: input.groupSlots,
+    })
+  ) {
+    return selectSingleMaterialDescriptor(
+      materialDescriptorsFromText(input.primaryMaterialDescriptor),
+    )
+  }
+  const inheritedDescriptors = allMaterialRecords.flatMap((record) => (
+    materialDescriptorsFromText(`${record.fact.subject} ${record.fact.value} ${record.fact.note ?? ''}`)
   ))
-  if (supportedDescriptors.length !== 1 || supportedFamilies.length !== 1) return undefined
-  return supportedFamilies[0] === modelFamily ? supportedDescriptors[0] : undefined
+  return selectSingleMaterialDescriptor(inheritedDescriptors)
 }
 
 function resolveNonMaterialModelDescriptor(input: {
@@ -1005,6 +1076,9 @@ function normalizeInstantiatedSku(input: {
   const modelByKey = new Map(
     (input.model?.bomLines ?? []).map((line) => [line.externalLineId, line] as const),
   )
+  const primaryMaterialDescriptor = input.group.costFamilies.find(
+    (family) => family.skuIds.includes(input.sku.externalSkuId),
+  )?.materialFamily
   const verticalSlot = input.group.componentSlots.find(
     (slot) => slot.componentKey === 'partition-vertical',
   )
@@ -1049,6 +1123,8 @@ function normalizeInstantiatedSku(input: {
             sku: input.sku,
             factSnapshot: input.factSnapshot,
             modelLine,
+            primaryMaterialDescriptor,
+            groupSlots: input.group.componentSlots,
           })
         : resolveNonMaterialModelDescriptor({
             category: slot.category,
@@ -1057,13 +1133,9 @@ function normalizeInstantiatedSku(input: {
       return compactInstantiatedBomLineSchema.parse({
         externalLineId: slot.componentKey,
         quantity,
-        unit: modelLine?.unit || (
-          slot.category === 'BOARD'
-            ? '块'
-            : ['PROCESSING', 'LABOR', 'PACKAGING'].includes(slot.category)
-              ? '套'
-              : '件'
-        ),
+        // A model may confuse a dimension token such as mm/cm/m with a count
+        // unit. The category Skill contract is the sole owner of line units.
+        unit: slot.unit,
         // For board slots, the shared blueprint formula must remain stable
         // across sibling SKUs. The model can fill genuinely unknown geometry,
         // but cannot override dimensions derived from the SKU's outer size.
diff --git a/furniture-3d-system/src/server/services/bom-costing/bom-costing-structure-knowledge.test.ts b/furniture-3d-system/src/server/services/bom-costing/bom-costing-structure-knowledge.test.ts
index bae72786..26329d70 100644
--- a/furniture-3d-system/src/server/services/bom-costing/bom-costing-structure-knowledge.test.ts
+++ b/furniture-3d-system/src/server/services/bom-costing/bom-costing-structure-knowledge.test.ts
@@ -63,8 +63,8 @@ describe('BOM 通用结构知识与确定性蓝图', () => {
       snapshot.skus.map((item) => item.externalSkuId),
     )
     expect(result.structureGroups[0]?.componentSlots).toEqual(expect.arrayContaining([
-      expect.objectContaining({ componentKey: 'enclosure-bottom', required: true }),
-      expect.objectContaining({ componentKey: 'processing-main', required: true }),
+      expect.objectContaining({ componentKey: 'enclosure-bottom', required: true, unit: '块' }),
+      expect.objectContaining({ componentKey: 'processing-main', required: true, unit: '套' }),
       expect.objectContaining({ componentKey: 'labor-assembly', required: true }),
       expect.objectContaining({ componentKey: 'packaging-set', required: true }),
     ]))
diff --git a/furniture-3d-system/src/server/services/bom-costing/bom-costing-structure-knowledge.ts b/furniture-3d-system/src/server/services/bom-costing/bom-costing-structure-knowledge.ts
index 84525853..44b70641 100644
--- a/furniture-3d-system/src/server/services/bom-costing/bom-costing-structure-knowledge.ts
+++ b/furniture-3d-system/src/server/services/bom-costing/bom-costing-structure-knowledge.ts
@@ -145,10 +145,12 @@ function buildComponentSlot(input: {
     role: input.component.role,
     category: input.component.category,
     partName: input.component.partName,
+    unit: input.component.unit,
     required: input.draft ? input.definitionRequired : required,
     quantityRule: input.component.quantityRule,
     dimensionRule: input.component.dimensionRule,
     materialScope: input.component.materialScope,
+    primaryMaterialSlot: input.component.primaryMaterialSlot === true,
     evidenceFactIds,
     confidence,
     reviewFlags: facts.length === 0
diff --git a/furniture-3d-system/src/server/services/bom-costing/category-skills/cabinet-bookshelf.skill.ts b/furniture-3d-system/src/server/services/bom-costing/category-skills/cabinet-bookshelf.skill.ts
index 012b29c3..c6736d6c 100644
--- a/furniture-3d-system/src/server/services/bom-costing/category-skills/cabinet-bookshelf.skill.ts
+++ b/furniture-3d-system/src/server/services/bom-costing/category-skills/cabinet-bookshelf.skill.ts
@@ -34,17 +34,17 @@ export const cabinetBookshelfCategorySkill = {
     { signalKey: 'exclude-soft-cabinet', terms: ['布艺收纳柜', '折叠布柜', '塑料抽屉柜'], weight: 30, reason: '软体或塑料成品不适用板式柜体结构。', hard: true },
   ],
   requiredComponents: [
-    { componentKey: 'enclosure-side', role: 'ENCLOSURE', category: 'BOARD', partName: '左右侧板', stableQuantity: 2, unit: '块', quantityRule: '同一结构组固定 2 块。', dimensionRule: '高度按柜体高度，宽度按有效深度。', materialScope: '柜体主体材质。', keywords: ['侧板', '柜体侧板'] },
-    { componentKey: 'enclosure-top', role: 'ENCLOSURE', category: 'BOARD', partName: '柜体顶板', stableQuantity: 1, unit: '块', quantityRule: '每个连续柜体固定 1 块。', dimensionRule: '长度随柜宽，宽度随有效深度。', materialScope: '柜体主体材质。', keywords: ['顶板', '柜顶'] },
-    { componentKey: 'enclosure-bottom', role: 'ENCLOSURE', category: 'BOARD', partName: '柜体底板', stableQuantity: 1, unit: '块', quantityRule: '每个连续柜体固定 1 块。', dimensionRule: '长度随柜宽，宽度随有效深度。', materialScope: '柜体主体材质。', keywords: ['底板', '柜底'] },
+    { componentKey: 'enclosure-side', role: 'ENCLOSURE', category: 'BOARD', partName: '左右侧板', stableQuantity: 2, unit: '块', primaryMaterialSlot: true, quantityRule: '同一结构组固定 2 块。', dimensionRule: '高度按柜体高度，宽度按有效深度。', materialScope: '柜体主体材质。', keywords: ['侧板', '柜体侧板'] },
+    { componentKey: 'enclosure-top', role: 'ENCLOSURE', category: 'BOARD', partName: '柜体顶板', stableQuantity: 1, unit: '块', primaryMaterialSlot: true, quantityRule: '每个连续柜体固定 1 块。', dimensionRule: '长度随柜宽，宽度随有效深度。', materialScope: '柜体主体材质。', keywords: ['顶板', '柜顶'] },
+    { componentKey: 'enclosure-bottom', role: 'ENCLOSURE', category: 'BOARD', partName: '柜体底板', stableQuantity: 1, unit: '块', primaryMaterialSlot: true, quantityRule: '每个连续柜体固定 1 块。', dimensionRule: '长度随柜宽，宽度随有效深度。', materialScope: '柜体主体材质。', keywords: ['底板', '柜底'] },
     { componentKey: 'back-panel', role: 'COVER', category: 'BOARD', partName: '背板', stableQuantity: 1, unit: '块', quantityRule: '固定 1 组背板；拼接缝没有证据时不拆数量。', dimensionRule: '覆盖背部开口，板厚必须单独取证。', materialScope: '背板可与主体不同。', keywords: ['背板', '后板'] },
-    { componentKey: 'partition-shelf', role: 'PARTITION', category: 'BOARD', partName: '层板', stableQuantity: 3, unit: '块', quantityRule: '基础组固定 3 块；明确层数形成独立结构组。', dimensionRule: '长度按所在净开口，宽度按有效深度。', materialScope: '层板材质。', keywords: ['层板', '隔板', '搁板'], quantityByStructureKey: Object.fromEntries([2, 3, 4, 5, 6, 7, 8].map((count) => [`SHELF_COUNT_${count}`, count])) },
+    { componentKey: 'partition-shelf', role: 'PARTITION', category: 'BOARD', partName: '层板', stableQuantity: 3, unit: '块', primaryMaterialSlot: true, quantityRule: '基础组固定 3 块；明确层数形成独立结构组。', dimensionRule: '长度按所在净开口，宽度按有效深度。', materialScope: '层板材质。', keywords: ['层板', '隔板', '搁板'], quantityByStructureKey: Object.fromEntries([2, 3, 4, 5, 6, 7, 8].map((count) => [`SHELF_COUNT_${count}`, count])) },
     CONNECTOR_COMPONENT,
     ...COMMON_COST_COMPONENTS,
   ],
   optionalComponents: [
-    { componentKey: 'partition-vertical', role: 'PARTITION', category: 'BOARD', partName: '竖向隔板', stableQuantity: 1, unit: '块', quantityRule: '分栏结构组固定 1 块；更多分栏需专属事实。', dimensionRule: '按柜内净高和有效深度。', materialScope: '柜体主体材质。', keywords: ['竖隔板', '中竖板', '分栏'], requiredWhenStructureKeys: ['VERTICAL_DIVISION'] },
-    { componentKey: 'cover-door', role: 'COVER', category: 'BOARD', partName: '柜门', stableQuantity: 2, unit: '块', quantityRule: '带门结构组固定 2 扇；明确门数需独立结构组或 SKU 专属事实。', dimensionRule: '按柜体开口范围推导。', materialScope: '门板材质和表面处理。', keywords: ['柜门', '门板'], requiredWhenStructureKeys: ['HINGED_DOOR', 'SLIDING_DOOR'] },
+    { componentKey: 'partition-vertical', role: 'PARTITION', category: 'BOARD', partName: '竖向隔板', stableQuantity: 1, unit: '块', primaryMaterialSlot: true, quantityRule: '分栏结构组固定 1 块；更多分栏需专属事实。', dimensionRule: '按柜内净高和有效深度。', materialScope: '柜体主体材质。', keywords: ['竖隔板', '中竖板', '分栏'], requiredWhenStructureKeys: ['VERTICAL_DIVISION'] },
+    { componentKey: 'cover-door', role: 'COVER', category: 'BOARD', partName: '柜门', stableQuantity: 2, unit: '块', primaryMaterialSlot: true, quantityRule: '带门结构组固定 2 扇；明确门数需独立结构组或 SKU 专属事实。', dimensionRule: '按柜体开口范围推导。', materialScope: '门板材质和表面处理。', keywords: ['柜门', '门板'], requiredWhenStructureKeys: ['HINGED_DOOR', 'SLIDING_DOOR'] },
     { componentKey: 'motion-hinge', role: 'MOTION', category: 'ACCESSORY', partName: '柜门铰链机构', stableQuantity: 1, unit: '套', quantityRule: '平开门结构组固定 1 套。', dimensionRule: '型号和杯孔无证据时待复核。', materialScope: '铰链和紧固件。', keywords: ['铰链', '合页'], requiredWhenStructureKeys: ['HINGED_DOOR'] },
     { componentKey: 'motion-sliding-door', role: 'MOTION', category: 'ACCESSORY', partName: '移门轨道机构', stableQuantity: 1, unit: '套', quantityRule: '移门结构组固定 1 套。', dimensionRule: '轨道长度随开口宽度。', materialScope: '轨道、滑轮和限位件。', keywords: ['移门', '推拉门', '轨道'], requiredWhenStructureKeys: ['SLIDING_DOOR'] },
     { componentKey: 'drawer-box', role: 'PARTITION', category: 'BOARD', partName: '抽屉盒板件', stableQuantity: 1, unit: '套', quantityRule: '带抽结构组固定 1 套；更多抽屉需专属事实。', dimensionRule: '按抽屉开口和柜内深度。', materialScope: '抽屉板件。', keywords: ['抽屉'], requiredWhenStructureKeys: ['DRAWER_PRESENT'] },
diff --git a/furniture-3d-system/src/server/services/bom-costing/category-skills/hard-seating.skill.ts b/furniture-3d-system/src/server/services/bom-costing/category-skills/hard-seating.skill.ts
index abb83470..53853490 100644
--- a/furniture-3d-system/src/server/services/bom-costing/category-skills/hard-seating.skill.ts
+++ b/furniture-3d-system/src/server/services/bom-costing/category-skills/hard-seating.skill.ts
@@ -24,7 +24,7 @@ export const hardSeatingCategorySkill = {
     { signalKey: 'exclude-bench-storage', terms: ['储物凳', '收纳凳'], weight: 20, reason: '带软包或箱体的储物凳需要其他专用结构。', hard: true },
   ],
   requiredComponents: [
-    { componentKey: 'surface-seat', role: 'SURFACE', category: 'BOARD', partName: '座面或座板', stableQuantity: 1, unit: '件', quantityRule: '每个独立椅凳固定 1 个座面；套装件数进入成本组。', dimensionRule: '按座面标注或整机比例推导，厚度独立取证。', materialScope: '木板、塑料或金属硬质座面。', keywords: ['座面', '座板', '凳面'] },
+    { componentKey: 'surface-seat', role: 'SURFACE', category: 'BOARD', partName: '座面或座板', stableQuantity: 1, unit: '件', primaryMaterialSlot: true, quantityRule: '每个独立椅凳固定 1 个座面；套装件数进入成本组。', dimensionRule: '按座面标注或整机比例推导，厚度独立取证。', materialScope: '木板、塑料或金属硬质座面。', keywords: ['座面', '座板', '凳面'] },
     { componentKey: 'support-seat', role: 'SUPPORT', category: 'BOARD', partName: '腿架与主体支撑', stableQuantity: 4, unit: '件', quantityRule: '普通四腿结构固定 4 件；框架/中柱结构独立分组。', dimensionRule: '由座高和支撑关系推导。', materialScope: '木材或金属支撑。', keywords: ['椅腿', '凳腿', '腿架', '支撑'], quantityByStructureKey: { FRAME_BASE: 1, PEDESTAL_BASE: 1 } },
     { componentKey: 'support-seat-brace', role: 'SUPPORT', category: 'BOARD', partName: '座下框与横撑', stableQuantity: 1, unit: '套', quantityRule: '同结构组固定 1 套座下框与横撑。', dimensionRule: '按座面下方连接边界推导。', materialScope: '木横撑、金属管或整体框架。', keywords: ['横撑', '座框', '下框'] },
     CONNECTOR_COMPONENT,
diff --git a/furniture-3d-system/src/server/services/bom-costing/category-skills/registry.ts b/furniture-3d-system/src/server/services/bom-costing/category-skills/registry.ts
index 78315eb4..50946050 100644
--- a/furniture-3d-system/src/server/services/bom-costing/category-skills/registry.ts
+++ b/furniture-3d-system/src/server/services/bom-costing/category-skills/registry.ts
@@ -138,6 +138,14 @@ function skillDefinitionIssues(skill: BomCostingCategorySkill) {
   const componentKeys = allComponents.map((component) => component.componentKey)
   if (componentKeys.length !== new Set(componentKeys).size) issues.push('存在重复 componentKey')
   if (skill.requiredComponents.length === 0) issues.push('缺少必要部件')
+  if (!allComponents.some((component) => component.primaryMaterialSlot)) {
+    issues.push('缺少主体材质继承槽位')
+  }
+  for (const component of allComponents) {
+    if (component.primaryMaterialSlot && component.category !== 'BOARD') {
+      issues.push(`主体材质槽位 ${component.componentKey} 必须是 BOARD`)
+    }
+  }
   const componentKeySet = new Set(componentKeys)
   for (const relation of skill.relations) {
     if (!componentKeySet.has(relation.fromComponentKey) || !componentKeySet.has(relation.toComponentKey)) {
diff --git a/furniture-3d-system/src/server/services/bom-costing/category-skills/storage-rack.skill.ts b/furniture-3d-system/src/server/services/bom-costing/category-skills/storage-rack.skill.ts
index 82e0ca4f..41effd3c 100644
--- a/furniture-3d-system/src/server/services/bom-costing/category-skills/storage-rack.skill.ts
+++ b/furniture-3d-system/src/server/services/bom-costing/category-skills/storage-rack.skill.ts
@@ -35,7 +35,7 @@ export const storageRackCategorySkill = {
   ],
   requiredComponents: [
     { componentKey: 'support-upright', role: 'SUPPORT', category: 'BOARD', partName: '立柱或侧架', stableQuantity: 4, unit: '件', quantityRule: '基础开放架固定 4 根立柱；双侧架结构组固定 2 组。', dimensionRule: '高度随整机高度，截面和壁厚必须单独取证。', materialScope: '木质或金属支撑。', keywords: ['立柱', '侧架', '支架'], quantityByStructureKey: { SIDE_FRAME: 2 } },
-    { componentKey: 'partition-shelf', role: 'PARTITION', category: 'BOARD', partName: '置物层板', stableQuantity: 3, unit: '块', quantityRule: '基础组固定 3 层；明确层数形成独立结构组。', dimensionRule: '长宽按层架开口与整机深度。', materialScope: '木质、板材或金属层板。', keywords: ['层板', '置物板', '搁板'], quantityByStructureKey: Object.fromEntries([2, 3, 4, 5, 6, 7, 8].map((count) => [`TIER_COUNT_${count}`, count])) },
+    { componentKey: 'partition-shelf', role: 'PARTITION', category: 'BOARD', partName: '置物层板', stableQuantity: 3, unit: '块', primaryMaterialSlot: true, quantityRule: '基础组固定 3 层；明确层数形成独立结构组。', dimensionRule: '长宽按层架开口与整机深度。', materialScope: '木质、板材或金属层板。', keywords: ['层板', '置物板', '搁板'], quantityByStructureKey: Object.fromEntries([2, 3, 4, 5, 6, 7, 8].map((count) => [`TIER_COUNT_${count}`, count])) },
     { componentKey: 'support-cross-brace', role: 'SUPPORT', category: 'STEEL', partName: '横撑与稳定件', stableQuantity: 2, unit: '件', quantityRule: '基础组固定 2 件横撑；斜撑结构按独立组冻结。', dimensionRule: '按立柱间净距和稳定关系推导。', materialScope: '木横撑、金属管或拉条。', keywords: ['横撑', '斜撑', '拉条'] },
     { componentKey: 'hardware-feet', role: 'HARDWARE', category: 'ACCESSORY', partName: '脚垫或调平脚', stableQuantity: 4, unit: '个', quantityRule: '按基础支撑点固定 4 个；侧架结构需专属事实调整。', dimensionRule: '规格无证据时待复核。', materialScope: '脚垫、调平脚和端塞。', keywords: ['脚垫', '调平脚', '端塞'] },
     CONNECTOR_COMPONENT,
diff --git a/furniture-3d-system/src/server/services/bom-costing/category-skills/table.skill.ts b/furniture-3d-system/src/server/services/bom-costing/category-skills/table.skill.ts
index 16fad400..fd6ed1fe 100644
--- a/furniture-3d-system/src/server/services/bom-costing/category-skills/table.skill.ts
+++ b/furniture-3d-system/src/server/services/bom-costing/category-skills/table.skill.ts
@@ -24,7 +24,7 @@ export const tableCategorySkill = {
     { signalKey: 'exclude-soft-table', terms: ['折叠布桌', '充气桌'], weight: 30, reason: '软体或充气产品不适用硬体桌 Skill。', hard: true },
   ],
   requiredComponents: [
-    { componentKey: 'surface-main', role: 'SURFACE', category: 'BOARD', partName: '主桌面', stableQuantity: 1, unit: '块', quantityRule: '普通桌结构组固定 1 块；拼接、折叠或延伸结构必须独立分组。', dimensionRule: '长宽以 SKU 外形和明确桌面标注为先；板厚独立取证。', materialScope: '当前 SKU 的桌面主体材质。', keywords: ['台面', '桌面', '面板'] },
+    { componentKey: 'surface-main', role: 'SURFACE', category: 'BOARD', partName: '主桌面', stableQuantity: 1, unit: '块', primaryMaterialSlot: true, quantityRule: '普通桌结构组固定 1 块；拼接、折叠或延伸结构必须独立分组。', dimensionRule: '长宽以 SKU 外形和明确桌面标注为先；板厚独立取证。', materialScope: '当前 SKU 的桌面主体材质。', keywords: ['台面', '桌面', '面板'] },
     { componentKey: 'support-leg', role: 'SUPPORT', category: 'BOARD', partName: '桌腿或主体底座', stableQuantity: 4, unit: '件', quantityRule: '普通四腿桌固定 4 件；中柱底座结构组固定 1 件。', dimensionRule: '由桌高和连接关系推导，不复制整机长宽。', materialScope: '木质或金属承重支撑。', keywords: ['桌腿', '支腿', '底座', '中柱'], quantityByStructureKey: { PEDESTAL_BASE: 1, TRESTLE_BASE: 2 } },
     { componentKey: 'support-apron', role: 'SUPPORT', category: 'BOARD', partName: '桌面下框与横撑', stableQuantity: 1, unit: '套', quantityRule: '同一支撑结构组固定 1 套。', dimensionRule: '按桌面下方连接边界推导。', materialScope: '围板、横撑或金属桌架。', keywords: ['围板', '横撑', '桌架', '下框'] },
     CONNECTOR_COMPONENT,
@@ -32,7 +32,7 @@ export const tableCategorySkill = {
   ],
   optionalComponents: [
     { componentKey: 'motion-extension', role: 'MOTION', category: 'ACCESSORY', partName: '伸缩与锁止机构', stableQuantity: 1, unit: '套', quantityRule: '伸缩桌结构组固定 1 套。', dimensionRule: '需核对收拢和展开尺寸、轨道行程及锁止位置。', materialScope: '伸缩轨、联动件、锁止和限位件。', keywords: ['伸缩', '延伸', '拉伸', '锁止'], requiredWhenStructureKeys: ['EXTENSION_TABLE'] },
-    { componentKey: 'surface-extension-leaf', role: 'SURFACE', category: 'BOARD', partName: '延伸桌板', stableQuantity: 1, unit: '块', quantityRule: '伸缩桌结构组固定 1 块；多块延伸板需 SKU 专属事实。', dimensionRule: '按展开前后长度差和桌面宽度推导。', materialScope: '通常与主桌面同材质，仍需确认。', keywords: ['延伸板', '活动桌板', '加长板'], requiredWhenStructureKeys: ['EXTENSION_TABLE'] },
+    { componentKey: 'surface-extension-leaf', role: 'SURFACE', category: 'BOARD', partName: '延伸桌板', stableQuantity: 1, unit: '块', primaryMaterialSlot: true, quantityRule: '伸缩桌结构组固定 1 块；多块延伸板需 SKU 专属事实。', dimensionRule: '按展开前后长度差和桌面宽度推导。', materialScope: '通常与主桌面同材质，仍需确认。', keywords: ['延伸板', '活动桌板', '加长板'], requiredWhenStructureKeys: ['EXTENSION_TABLE'] },
     { componentKey: 'motion-folding', role: 'MOTION', category: 'ACCESSORY', partName: '折叠铰接机构', stableQuantity: 1, unit: '套', quantityRule: '折叠桌结构组固定 1 套。', dimensionRule: '核对折叠轴、锁止和展开支撑。', materialScope: '铰链、转轴、锁止和紧固件。', keywords: ['折叠', '合页', '转轴'], requiredWhenStructureKeys: ['FOLDING_TABLE'] },
     { componentKey: 'drawer-box', role: 'PARTITION', category: 'BOARD', partName: '桌下抽屉盒', stableQuantity: 1, unit: '套', quantityRule: '带抽桌结构组固定 1 套。', dimensionRule: '按桌下净空与抽屉开口推导。', materialScope: '抽屉板件。', keywords: ['抽屉'], requiredWhenStructureKeys: ['DRAWER_PRESENT'] },
     { componentKey: 'motion-drawer', role: 'MOTION', category: 'ACCESSORY', partName: '桌下抽屉导轨', stableQuantity: 1, unit: '套', quantityRule: '每套抽屉盒配置成对导轨。', dimensionRule: '导轨长度不超过桌下有效深度。', materialScope: '导轨、拉手和紧固件。', keywords: ['抽屉', '导轨'], requiredWhenStructureKeys: ['DRAWER_PRESENT'] },
diff --git a/furniture-3d-system/src/server/services/bom-costing/category-skills/types.ts b/furniture-3d-system/src/server/services/bom-costing/category-skills/types.ts
index 1ea90ace..1f4cd591 100644
--- a/furniture-3d-system/src/server/services/bom-costing/category-skills/types.ts
+++ b/furniture-3d-system/src/server/services/bom-costing/category-skills/types.ts
@@ -67,6 +67,11 @@ export interface BomCostingCategoryComponentDefinition {
   keywords: readonly string[]
   stableQuantity: number
   unit: string
+  /**
+   * Explicit Skill-owned allowlist for inheriting the cost family's single
+   * primary material. Unmarked components require their own material fact.
+   */
+  primaryMaterialSlot?: boolean
   requiredWhenStructureKeys?: readonly string[]
   quantityByStructureKey?: Readonly<Record<string, number>>
 }
diff --git a/furniture-3d-system/src/server/services/bom-costing/category-skills/wardrobe.skill.ts b/furniture-3d-system/src/server/services/bom-costing/category-skills/wardrobe.skill.ts
index 8c70dedc..babef7e2 100644
--- a/furniture-3d-system/src/server/services/bom-costing/category-skills/wardrobe.skill.ts
+++ b/furniture-3d-system/src/server/services/bom-costing/category-skills/wardrobe.skill.ts
@@ -103,6 +103,7 @@ export const wardrobeCategorySkill = {
     {
       componentKey: 'enclosure-side', role: 'ENCLOSURE', category: 'BOARD',
       partName: '左右侧板', stableQuantity: 2, unit: '块',
+      primaryMaterialSlot: true,
       quantityRule: '同一结构组固定 2 块；只有明确分柜体或 SKU 专属数量事实才能改变。',
       dimensionRule: '高度接近柜体高度，深度接近有效深度；板厚独立取证。',
       materialScope: '柜体主体材质。', keywords: ['侧板', '柜体侧板', '侧框'],
@@ -110,6 +111,7 @@ export const wardrobeCategorySkill = {
     {
       componentKey: 'enclosure-top', role: 'ENCLOSURE', category: 'BOARD',
       partName: '柜体顶板', stableQuantity: 1, unit: '块',
+      primaryMaterialSlot: true,
       quantityRule: '每个连续主柜体固定 1 块。',
       dimensionRule: '长度随 SKU 柜体宽度，宽度随有效深度。',
       materialScope: '柜体顶板材质。', keywords: ['顶板', '柜顶', '上横板'],
@@ -117,6 +119,7 @@ export const wardrobeCategorySkill = {
     {
       componentKey: 'enclosure-bottom', role: 'ENCLOSURE', category: 'BOARD',
       partName: '柜体底板', stableQuantity: 1, unit: '块',
+      primaryMaterialSlot: true,
       quantityRule: '每个连续主柜体固定 1 块，不因宽度或颜色变化拆分。',
       dimensionRule: '长度随 SKU 柜体宽度，宽度随有效深度。',
       materialScope: '柜体底板材质。', keywords: ['底板', '柜底', '下横板'],
@@ -131,6 +134,7 @@ export const wardrobeCategorySkill = {
     {
       componentKey: 'partition-vertical', role: 'PARTITION', category: 'BOARD',
       partName: '主竖隔板', stableQuantity: 1, unit: '块',
+      primaryMaterialSlot: true,
       quantityRule: '基础衣柜结构组固定 1 块；更多分区必须有 SKU 专属 factId 或独立布局组。',
       dimensionRule: '由柜内高度和有效深度推导，并与上下横板闭合。',
       materialScope: '柜内隔板材质。', keywords: ['竖隔板', '中竖板', '分区板'],
@@ -138,6 +142,7 @@ export const wardrobeCategorySkill = {
     {
       componentKey: 'partition-horizontal', role: 'PARTITION', category: 'BOARD',
       partName: '基础层板', stableQuantity: 1, unit: '块',
+      primaryMaterialSlot: true,
       quantityRule: '基础衣柜结构组固定 1 块；层板增减必须有 SKU 专属 factId 或独立布局组。',
       dimensionRule: '宽度按所在分区净宽，深度按柜内有效深度。',
       materialScope: '柜内层板材质。', keywords: ['层板', '横隔板', '隔板'],
@@ -145,6 +150,7 @@ export const wardrobeCategorySkill = {
     {
       componentKey: 'cover-door', role: 'COVER', category: 'BOARD',
       partName: '衣柜门板', stableQuantity: 2, unit: '块',
+      primaryMaterialSlot: true,
       quantityRule: '基础结构组固定 2 扇；明确门数形成独立结构组后按该组冻结。',
       dimensionRule: '按柜体开口推导，推拉门保留重叠量；不能用门缝臆造门数。',
       materialScope: '门板材质和表面处理。', keywords: ['门板', '柜门', '推拉门', '移门'],
@@ -186,6 +192,7 @@ export const wardrobeCategorySkill = {
     {
       componentKey: 'top-cabinet-side', role: 'ENCLOSURE', category: 'BOARD',
       partName: '顶柜左右侧板', stableQuantity: 2, unit: '块',
+      primaryMaterialSlot: true,
       quantityRule: '带顶柜结构组固定 2 块。',
       dimensionRule: '按顶柜高度和主柜有效深度推导。',
       materialScope: '顶柜主体材质。', keywords: ['顶柜侧板', '顶柜'],
@@ -194,6 +201,7 @@ export const wardrobeCategorySkill = {
     {
       componentKey: 'top-cabinet-horizontal', role: 'ENCLOSURE', category: 'BOARD',
       partName: '顶柜上下板', stableQuantity: 2, unit: '块',
+      primaryMaterialSlot: true,
       quantityRule: '带顶柜结构组固定 2 块。',
       dimensionRule: '长度按顶柜宽度，宽度按主柜有效深度。',
       materialScope: '顶柜主体材质。', keywords: ['顶柜顶板', '顶柜底板', '顶柜'],