diff --git a/.trellis/spec/hyb-oa/reimbursement-invoice-ocr.md b/.trellis/spec/hyb-oa/reimbursement-invoice-ocr.md
index 1fae21b9..8ebea450 100644
--- a/.trellis/spec/hyb-oa/reimbursement-invoice-ocr.md
+++ b/.trellis/spec/hyb-oa/reimbursement-invoice-ocr.md
@@ -691,6 +691,9 @@ await previewFileInWecom({ url: bundle.signedUrl, name: bundle.originalName, siz
 - `PATCH /api/reimbursements/:id` accepts nullable camel-case counterparts.
 - Detail response includes `travelSummary: { isTravel, purpose, location,
   startDate, endDate }`.
+- A privileged correction of an already submitted reimbursement writes an
+  `AuditLog` in the same transaction. Its `extra.changes` is an object keyed by
+  changed field name, with `{ before, after }` scalar snapshots.
 
 ### 3. Contracts
 
@@ -702,6 +705,17 @@ await previewFileInWecom({ url: bundle.signedUrl, name: bundle.originalName, siz
   min/max travel-item dates; location remains `未填写` and is never guessed.
 - Submit requires all four fields only for travel reimbursements; ordinary
   reimbursements remain unaffected.
+- An administrator correcting an already submitted amount, expense date,
+  travel-summary date or other core declared financial fact must record the
+  exact normalized `before` and `after` values in the restricted database audit
+  entry. Dates use `YYYY-MM-DD`; decimal amounts use canonical strings. The
+  audit also records a sanitized reason and operation/task reference.
+- The repository-visible Trellis task, docs and generated evidence record only
+  changed field names, invariant results and counts. They must not copy the
+  real purpose, location, amount, ticket content or audit payload.
+- Do not put attachment bytes, OCR/provider payloads or unrelated personal data
+  into `extra.changes`. Existing `system.audit.view` authorization remains the
+  access boundary for the database audit.
 
 ### 4. Validation & Error Matrix
 
@@ -710,18 +724,33 @@ await previewFileInWecom({ url: bundle.signedUrl, name: bundle.originalName, siz
 - Travel submit with missing fields -> `400` with
   `travelSummary: incomplete` and stable `missingFields`.
 - Edit while not draft/rejected -> existing `409 invalid_edit_status`.
+- Privileged correction changes a core declared fact but lacks a field-level
+  `before` or `after` snapshot -> abort the transaction; a field-name-only
+  audit is insufficient.
+- A historical correction is later found without its original snapshot -> do
+  not invent or reconstruct an audit value from memory. Record the evidence
+  gap and enforce the complete audit contract on future corrections.
 
 ### 5. Good/Base/Bad Cases
 
 - Good: travel item plus complete purpose/location/date range submits normally.
 - Base: office-supply reimbursement has no travel summary and is not blocked.
+- Good: an authorized date correction atomically updates the row and writes
+  `extra.changes.expenseDate = { before, after }` using synthetic or real
+  database values visible only to authorized auditors.
 - Bad: infer a destination from invoice OCR, attachment name or free text.
+- Bad: overwrite a submitted expense date and audit only
+  `changedFields: ["expenseDate"]`, leaving the original fact unrecoverable.
 
 ### 6. Tests Required
 
 - Prisma validation and all migrations against an empty PostgreSQL database.
 - Route tests for detail fallback, complete/incomplete travel submit, date order
   and non-travel compatibility; frontend typecheck/build and PC/mobile UI tests.
+- Privileged-correction tests use synthetic data and assert one transaction,
+  exact normalized `before/after`, sanitized reason, unchanged amount/material/
+  workflow invariants, rollback on audit failure and no real values in generated
+  repository evidence.
 
 ### 7. Wrong vs Correct
 
@@ -731,12 +760,26 @@ await previewFileInWecom({ url: bundle.signedUrl, name: bundle.originalName, siz
 travelLocation = invoice.ocrResult.sellerName;
 ```
 
+```js
+extra = { changedFields: ["expenseDate"] }; // original declared fact is lost
+```
+
 #### Correct
 
 ```js
 travelLocation = reimbursement.travel_location ?? null;
 ```
 
+```js
+extra = {
+  changes: {
+    expenseDate: { before: "2026-01-02", after: "2026-01-03" },
+  },
+  reason: "authorized_correction",
+  operationRef: "TASK-SYNTHETIC",
+};
+```
+
 ## Scenario: Payment Batch Receipt Attention Count
 
 ### 1. Scope / Trigger