TASK22168 endpoint account contract consistency slice

memory-bank/refactor-plan-actions-index.md

@@ -711,6 +711,41 @@ Status key: `[x] done`, `[ ] pending`
     - `tests/phase20/service-behaviour.test.cjs`
 - Re-run phase6–phase20 baseline tests and lint after rollback.
 
+### Phase 21 endpoint contract slice snapshot (2026-03-19)
+
+Status key: `[x] done`, `[ ] pending`
+
+1. `[x]` Confirm work item + branch from `origin/SIPS-Development`
+    - work item: `TASK22168`
+    - branch: `TASK22168-endpoint-account-contract-consistency`
+2. `[x]` Select next coherent low-risk endpoint contract slice after TASK22109
+    - selected handlers:
+        - `getaccounts_api`
+        - `getemailaccountcheck_api`
+        - `getpreferredlanguage_api`
+3. `[x]` Apply consistency pattern from TASK22109
+    - remove dead/noisy code (unused imports/commented debug remnants)
+    - standardize structured negative-path responses (missing required input + catch path)
+    - preserve success payload behavior
+4. `[x]` Add focused phase21 tests for endpoint slice
+    - added `tests/phase21/endpoint-handler-contract.test.cjs`
+    - extended `tests/phase21/api-contract-slice1.test.cjs` runner
+5. `[x]` Execute required validation
+    - `node tests/phase21/api-contract-slice1.test.cjs` -> pass
+    - `npm run lint` -> warnings only (pre-existing)
+
+### Phase 21 rollback notes
+
+- Revert files:
+    - `pages/api/endpoint/getaccounts_api.js`
+    - `pages/api/endpoint/getemailaccountcheck_api.js`
+    - `pages/api/endpoint/getpreferredlanguage_api.js`
+    - `tests/phase21/endpoint-handler-contract.test.cjs`
+    - `tests/phase21/api-contract-slice1.test.cjs`
+- Re-run:
+    - `node tests/phase21/api-contract-slice1.test.cjs`
+    - `npm run lint`
+
 ## Safe execution mode for migration chunks (required)
 
 To reduce terminal hangs during bulk migration work, run refactor chunks in **safe stepwise mode** instead of long chained commands.