diff --git a/src/main/services/team/ChangeExtractorService.ts b/src/main/services/team/ChangeExtractorService.ts
index fe46e6b0..6a75053d 100644
--- a/src/main/services/team/ChangeExtractorService.ts
+++ b/src/main/services/team/ChangeExtractorService.ts
@@ -46,6 +46,7 @@ import type { AgentChangeSet, ChangeStats, TaskChangeSetV2 } from '@shared/types
 
 const logger = createLogger('Service:ChangeExtractorService');
 const OPEN_CODE_AUTO_BACKFILL_ATTRIBUTION_MODE = 'strict-delivery' as const;
+const OPEN_CODE_AUTO_BACKFILL_EVIDENCE_MODE = 'chain-only' as const;
 const OPEN_CODE_MAX_DISCOVERED_LANES = 500;
 
 /** Кеш-запись: данные + mtime файла + время протухания */
@@ -425,6 +426,7 @@ export class ChangeExtractorService {
       sourceGeneration,
       deliveryContextFingerprint,
       attributionMode: OPEN_CODE_AUTO_BACKFILL_ATTRIBUTION_MODE,
+      evidenceMode: OPEN_CODE_AUTO_BACKFILL_EVIDENCE_MODE,
     });
     const now = Date.now();
     const cached = this.openCodeBackfillCache.get(cacheKey);
@@ -499,6 +501,7 @@ export class ChangeExtractorService {
         projectDir,
         workspaceRoot,
         attributionMode: OPEN_CODE_AUTO_BACKFILL_ATTRIBUTION_MODE,
+        evidenceMode: OPEN_CODE_AUTO_BACKFILL_EVIDENCE_MODE,
         ...(deliveryContext.filePath ? { deliveryContextPath: deliveryContext.filePath } : {}),
       });
       void appendOpenCodeTaskChangeDiag({
@@ -838,6 +841,7 @@ export class ChangeExtractorService {
     sourceGeneration?: string | null;
     deliveryContextFingerprint: string;
     attributionMode: typeof OPEN_CODE_AUTO_BACKFILL_ATTRIBUTION_MODE;
+    evidenceMode: typeof OPEN_CODE_AUTO_BACKFILL_EVIDENCE_MODE;
   }): string {
     return JSON.stringify({
       teamName: input.teamName,
@@ -848,6 +852,7 @@ export class ChangeExtractorService {
       sourceGeneration: input.sourceGeneration ?? '',
       deliveryContextFingerprint: input.deliveryContextFingerprint,
       attributionMode: input.attributionMode,
+      evidenceMode: input.evidenceMode,
     });
   }
 
diff --git a/src/main/services/team/opencode/bridge/OpenCodeBridgeCommandContract.ts b/src/main/services/team/opencode/bridge/OpenCodeBridgeCommandContract.ts
index 21660989..eca989d8 100644
--- a/src/main/services/team/opencode/bridge/OpenCodeBridgeCommandContract.ts
+++ b/src/main/services/team/opencode/bridge/OpenCodeBridgeCommandContract.ts
@@ -240,10 +240,17 @@ export interface OpenCodeBackfillTaskLedgerCommandBody {
   workspaceRoot?: string;
   deliveryContextPath?: string;
   attributionMode?: OpenCodeBackfillTaskLedgerAttributionMode;
+  evidenceMode?: OpenCodeBackfillTaskLedgerEvidenceMode;
   dryRun?: boolean;
 }
 
 export type OpenCodeBackfillTaskLedgerAttributionMode = 'strict-delivery' | 'compatible';
+export type OpenCodeBackfillTaskLedgerEvidenceMode =
+  | 'off'
+  | 'metadata-only'
+  | 'chain-only'
+  | 'snapshot-probe'
+  | 'snapshot-auto';
 
 export type OpenCodeBackfillTaskLedgerOutcome =
   | 'imported'
@@ -264,6 +271,12 @@ export interface OpenCodeBackfillTaskLedgerCommandData {
   workspaceRoot?: string;
   dryRun: boolean;
   attributionMode?: OpenCodeBackfillTaskLedgerAttributionMode;
+  evidenceMode?: OpenCodeBackfillTaskLedgerEvidenceMode;
+  strictWindowCandidateCount?: number;
+  openCodeDbFingerprint?: string;
+  deliveryLedgerFingerprint?: string;
+  snapshotShapeFingerprint?: string;
+  retryAfterReason?: string;
   scannedSessions: number;
   scannedToolparts: number;
   candidateEvents: number;
diff --git a/src/main/services/team/opencode/bridge/OpenCodeReadinessBridge.ts b/src/main/services/team/opencode/bridge/OpenCodeReadinessBridge.ts
index ad4dff69..cba24f84 100644
--- a/src/main/services/team/opencode/bridge/OpenCodeReadinessBridge.ts
+++ b/src/main/services/team/opencode/bridge/OpenCodeReadinessBridge.ts
@@ -308,6 +308,7 @@ export class OpenCodeReadinessBridge implements OpenCodeTeamRuntimeBridgePort {
       ...(input.workspaceRoot ? { workspaceRoot: input.workspaceRoot } : {}),
       dryRun: input.dryRun === true,
       ...(input.attributionMode ? { attributionMode: input.attributionMode } : {}),
+      ...(input.evidenceMode ? { evidenceMode: input.evidenceMode } : {}),
       scannedSessions: 0,
       scannedToolparts: 0,
       candidateEvents: 0,
diff --git a/test/main/services/team/ChangeExtractorService.test.ts b/test/main/services/team/ChangeExtractorService.test.ts
index fdd32b5b..302c35b1 100644
--- a/test/main/services/team/ChangeExtractorService.test.ts
+++ b/test/main/services/team/ChangeExtractorService.test.ts
@@ -1058,6 +1058,7 @@ describe('ChangeExtractorService', () => {
         projectDir,
         workspaceRoot: projectPath,
         attributionMode: 'strict-delivery',
+        evidenceMode: 'chain-only',
       })
     );
     expect(workerClient.computeTaskChanges).not.toHaveBeenCalled();
@@ -1182,6 +1183,7 @@ describe('ChangeExtractorService', () => {
           workspaceRoot: projectPath,
           deliveryContextPath: expect.stringContaining('delivery-context.json'),
           attributionMode: 'strict-delivery',
+          evidenceMode: 'chain-only',
         })
       );
     });