diff --git a/.changeset/read-back-failed-named-wire-row.md b/.changeset/read-back-failed-named-wire-row.md
new file mode 100644
index 0000000000..d40643f49b
--- /dev/null
+++ b/.changeset/read-back-failed-named-wire-row.md
@@ -0,0 +1,21 @@
+---
+"@objectstack/spec": minor
+"@objectstack/rest": minor
+---
+
+feat(spec,rest): register `READ_BACK_FAILED` as a named wire row and map it in `handleApprovalError` (#13182)
+
+The `READ_BACK_FAILED:` refusal (#12769: an approval mutation succeeded but its
+post-write read-back is filtered out by the caller's organization scope) used
+to reach REST clients through each route's terminal 500 arm — a registered
+code (`APPROVAL_RECALL_FAILED` and siblings) whose name does not describe what
+happened, with the accurate sentence only in the body.
+
+Following the `RESUME_FAILED` precedent (a genuine server-side inconsistency,
+but named), `READ_BACK_FAILED` is now registered in the ADR-0112 error-code
+ledger and `handleApprovalError` maps the `READ_BACK_FAILED:` message prefix to
+HTTP 500 with `code: 'READ_BACK_FAILED'` on the wire. The 500 semantics stay —
+it is genuinely a server-side inconsistency; the write is recorded and NOT
+rolled back, and the row can be read back with a system or
+matching-organization context. Additive vocabulary only: no existing code,
+status, or message changes.
diff --git a/content/docs/references/api/contract.mdx b/content/docs/references/api/contract.mdx
index 1b5f9f85e8..88ad133f51 100644
--- a/content/docs/references/api/contract.mdx
+++ b/content/docs/references/api/contract.mdx
@@ -27,7 +27,7 @@ const result = ApiErrorSchema.parse(data);
 
 | Property | Type | Required | Description |
 | :--- | :--- | :--- | :--- |
-| **code** | `Enum<'VALIDATION_ERROR' \| 'INVALID_FIELD' \| 'MISSING_REQUIRED_FIELD' \| 'INVALID_FORMAT' \| 'VALUE_TOO_LONG' \| 'VALUE_TOO_SHORT' \| 'VALUE_OUT_OF_RANGE' \| … +290 more>` | ✅ | Error code (e.g. VALIDATION_ERROR; StandardErrorCode ∪ the ledger the serving side registers — ERROR_CODE_LEDGER for framework packages) |
+| **code** | `Enum<'VALIDATION_ERROR' \| 'INVALID_FIELD' \| 'MISSING_REQUIRED_FIELD' \| 'INVALID_FORMAT' \| 'VALUE_TOO_LONG' \| 'VALUE_TOO_SHORT' \| 'VALUE_OUT_OF_RANGE' \| … +291 more>` | ✅ | Error code (e.g. VALIDATION_ERROR; StandardErrorCode ∪ the ledger the serving side registers — ERROR_CODE_LEDGER for framework packages) |
 | **declaredCode** | `string` | optional | The producer-declared code, verbatim, when it is not a member of the closed `code` vocabulary — the open, author-authored channel (app-specific spellings; ADR-0112) |
 | **message** | `string` | ✅ | Readable error message |
 | **userMessage** | `string` | optional | Producer-marked user-facing refusal text, verbatim. Present exactly when the producer opted in at throw time; consumers render it to end users and keep their generic substitution for anything unmarked. Status-agnostic; never replaces `message`. |
@@ -261,6 +261,7 @@ const result = ApiErrorSchema.parse(data);
 * `PROJECT_PROVISIONING_FAILED`
 * `QUERY_OBJECT_MISMATCH`
 * `RAW_SQL_UNSUPPORTED`
+* `READ_BACK_FAILED`
 * `READ_SCOPE_COMPILE_FAILED`
 * `RECORD_GONE`
 * `RECORD_LOCKED`
diff --git a/content/docs/references/api/error-code-ledger.mdx b/content/docs/references/api/error-code-ledger.mdx
index 67f24b3b9b..18e39f4ab2 100644
--- a/content/docs/references/api/error-code-ledger.mdx
+++ b/content/docs/references/api/error-code-ledger.mdx
@@ -365,6 +365,7 @@ const result = ErrorCode.parse(data);
 * `PROJECT_PROVISIONING_FAILED`
 * `QUERY_OBJECT_MISMATCH`
 * `RAW_SQL_UNSUPPORTED`
+* `READ_BACK_FAILED`
 * `READ_SCOPE_COMPILE_FAILED`
 * `RECORD_GONE`
 * `RECORD_LOCKED`
diff --git a/packages/plugins/plugin-approvals/src/approval-service.ts b/packages/plugins/plugin-approvals/src/approval-service.ts
index d1b7d684c7..3fbf4ebae9 100644
--- a/packages/plugins/plugin-approvals/src/approval-service.ts
+++ b/packages/plugins/plugin-approvals/src/approval-service.ts
@@ -4780,7 +4780,7 @@ export class ApprovalService implements IApprovalService {
       throw new Error(
         `READ_BACK_FAILED: the write to approval request '${requestId}' was recorded, but the updated row is `
         + `not visible inside the caller's organization scope, so the result envelope cannot be built. The write `
-        + `is NOT rolled back — read the request back with a system or matching-organization context (#12769).`,
+        + `is NOT rolled back — read the request back with a system or matching-organization context.`,
       );
     }
     return fresh;
diff --git a/packages/rest/src/rest-approvals-wire-codes.test.ts b/packages/rest/src/rest-approvals-wire-codes.test.ts
index 23d2e93702..4745193b7e 100644
--- a/packages/rest/src/rest-approvals-wire-codes.test.ts
+++ b/packages/rest/src/rest-approvals-wire-codes.test.ts
@@ -115,6 +115,31 @@ describe('approvals wire codes are registered vocabulary (#8885)', () => {
         ).toBe(true);
     });
 
+    // [#13182] `READ_BACK_FAILED` is a NAMED wire row (the RESUME_FAILED
+    // precedent: a genuine server-side inconsistency, but named): the write is
+    // recorded and NOT rolled back, the read-back is org-filtered, and the
+    // 500 semantics stay. Pinned here so the prefix→code mapping and ledger
+    // membership cannot regress independently: without the mapping arm this
+    // throw would ride the template-generated `APPROVAL_APPROVE_FAILED` arm —
+    // a registered code whose name does not describe what happened.
+    it('an org-filtered read-back on approve answers 500 READ_BACK_FAILED — named, not the template fallback', async () => {
+        const rest = boot({
+            decide: vi.fn().mockRejectedValue(new Error(
+                "READ_BACK_FAILED: the write to approval request 'req_1' was recorded, but the updated row is "
+                + "not visible inside the caller's organization scope, so the result envelope cannot be built. "
+                + 'The write is NOT rolled back — read the request back with a system or matching-organization context.',
+            )),
+        });
+        const answer = await drive(rest, 'POST', `${REQ}/approve`);
+        expect(answer.status).toBe(500);
+        expect(answer.body?.code).toBe('READ_BACK_FAILED');
+        expect(answer.body?.error).toMatch(/^the write to approval request 'req_1' was recorded/);
+        expect(
+            ApiErrorSchema.safeParse({ code: answer.body?.code, message: answer.body?.error }).success,
+            'READ_BACK_FAILED must be in StandardErrorCode ∪ ERROR_CODE_LEDGER',
+        ).toBe(true);
+    });
+
     it('an unmapped service fault on approve answers 500 APPROVAL_APPROVE_FAILED — the template-generated arm, live', async () => {
         const rest = boot({
             decide: vi.fn().mockRejectedValue(new Error('kaboom: not in the mapping table')),
diff --git a/packages/rest/src/rest-server.ts b/packages/rest/src/rest-server.ts
index 3eca151d4b..d538f059f3 100644
--- a/packages/rest/src/rest-server.ts
+++ b/packages/rest/src/rest-server.ts
@@ -10865,6 +10865,13 @@ export class RestServer {
                 // server-side inconsistency, but named, so the client can say
                 // which run needs an operator instead of showing a bare 500.
                 [/^RESUME_FAILED/, 500, 'RESUME_FAILED'],
+                // The write IS recorded and NOT rolled back, but the updated
+                // row is invisible inside the caller's organization scope, so
+                // the result envelope cannot be built. Same class as
+                // RESUME_FAILED — a genuine server-side inconsistency, named
+                // (#13182): read the request back with a system or
+                // matching-organization context.
+                [/^READ_BACK_FAILED/, 500, 'READ_BACK_FAILED'],
             ];
             for (const [re, status, code] of mapping) {
                 if (re.test(msg)) {
diff --git a/packages/spec/src/api/error-code-ledger.zod.ts b/packages/spec/src/api/error-code-ledger.zod.ts
index 260cf2ec7b..b09da99697 100644
--- a/packages/spec/src/api/error-code-ledger.zod.ts
+++ b/packages/spec/src/api/error-code-ledger.zod.ts
@@ -210,6 +210,7 @@ export const ERROR_CODE_LEDGER = {
     'PROJECT_NOT_FOUND',
     'PROJECT_PROVISIONING',       // project exists but is still provisioning
     'PROJECT_PROVISIONING_FAILED',
+    'READ_BACK_FAILED',           // approval write recorded, but its read-back is filtered by the caller's org scope — the result envelope cannot be built; the write is NOT rolled back
     'REPORTS_LIST_FAILED',
     'REPORT_DELETE_FAILED',
     'REPORT_GET_FAILED',
diff --git a/packages/spec/src/contracts/approval-service.ts b/packages/spec/src/contracts/approval-service.ts
index 71c396857f..68ae52f175 100644
--- a/packages/spec/src/contracts/approval-service.ts
+++ b/packages/spec/src/contracts/approval-service.ts
@@ -573,6 +573,12 @@ export interface ApprovalDecisionResult {
 
 /**
  * Public contract — the node-era approval runtime.
+ *
+ * Every mutation echoes the row it just changed. A mutation whose post-write
+ * read-back is filtered out by the caller's organization scope throws
+ * `READ_BACK_FAILED` (HTTP 500 over REST, registered in the ADR-0112 ledger):
+ * the write is recorded and NOT rolled back — read the request back with a
+ * system or matching-organization context.
  */
 export interface IApprovalService {
   /**