diff --git a/sdk/src/query/phase-uat-passed.test.ts b/sdk/src/query/phase-uat-passed.test.ts
index ff33163fc..69f247ca2 100644
--- a/sdk/src/query/phase-uat-passed.test.ts
+++ b/sdk/src/query/phase-uat-passed.test.ts
@@ -272,4 +272,34 @@ expected: thing
       await rm(localTmp, { recursive: true, force: true });
     }
   });
+
+  it("emits CASE_MISMATCH reason when result value is \"PASS\" (uppercase variant of pass)", async () => {
+    const localTmp = await mkdtemp(join(tmpdir(), 'gsd-uat-c10-'));
+    try {
+      const phaseDir = join(localTmp, '.planning', 'phases', '05-case-mismatch');
+      await mkdir(phaseDir, { recursive: true });
+      const content = `---
+status: complete
+phase: 5
+source: roadmap
+started: 2026-05-18T00:00:00Z
+updated: 2026-05-18T00:00:00Z
+---
+
+### 1. Uppercase pass item
+expected: thing happens
+result: PASS
+`;
+      await writeFile(join(phaseDir, '05-HUMAN-UAT.md'), content);
+
+      const result = await isPhaseUatPassed(localTmp, '5');
+      expect(result.passed).toBe(false);
+      expect(result.items.length).toBe(1);
+      expect(result.reasons.length).toBe(1);
+      expect(result.reasons[0].code).toBe(REASON_CODE.CASE_MISMATCH);
+      expect(result.reasons[0].capturedValue).toBe('PASS');
+    } finally {
+      await rm(localTmp, { recursive: true, force: true });
+    }
+  });
 });
diff --git a/sdk/src/query/phase-uat-passed.ts b/sdk/src/query/phase-uat-passed.ts
index 1dea2e76f..cfd1323f2 100644
--- a/sdk/src/query/phase-uat-passed.ts
+++ b/sdk/src/query/phase-uat-passed.ts
@@ -11,6 +11,7 @@ import { resolvePhaseDir } from './phase-list-queries.js';
 
 export const REASON_CODE = Object.freeze({
   NON_PASS_RESULT: 'non_pass_result',
+  CASE_MISMATCH: 'case_mismatch',
   NO_PHASE_DIR: 'no_phase_dir',
   NO_UAT_FILES: 'no_uat_files',
 } as const);
@@ -114,8 +115,12 @@ export async function isPhaseUatPassed(
     for (const item of parsed) {
       items.push(item);
       if (item.result !== 'pass') {
+        const code =
+          item.result.toLowerCase() === 'pass'
+            ? REASON_CODE.CASE_MISMATCH
+            : REASON_CODE.NON_PASS_RESULT;
         reasons.push({
-          code: REASON_CODE.NON_PASS_RESULT,
+          code,
           file: relFile,
           itemName: item.name,
           capturedValue: item.result,