diff --git a/.github/scripts/pr-gate-policy.test.mjs b/.github/scripts/pr-gate-policy.test.mjs
index bf1d64b..8443f9b 100644
--- a/.github/scripts/pr-gate-policy.test.mjs
+++ b/.github/scripts/pr-gate-policy.test.mjs
@@ -100,12 +100,12 @@ test("stale runs are cancelled per pull request", async () => {
     );
 });
 
-test("token-authored commits preserve the pull request context on manual dispatch", async () => {
+test("token-authored commits normalize manual dispatch PR numbers for every reusable workflow", async () => {
     const entry = await readWorkflow(ENTRY_WORKFLOW);
 
     assert.match(entry, /^\s{2}workflow_dispatch:\n\s{4}inputs:\n\s{6}pull_request_number:/m);
     assert.equal(
-        (entry.match(/pull_request_number: \$\{\{ inputs\.pull_request_number \|\| github\.event\.pull_request\.number \|\| 0 \}\}/g) ?? []).length,
+        (entry.match(/pull_request_number: \$\{\{ fromJSON\(format\('\{0\}', inputs\.pull_request_number \|\| github\.event\.pull_request\.number \|\| 0\)\) \}\}/g) ?? []).length,
         VALIDATION_WORKFLOWS.length,
     );
 });
@@ -118,7 +118,7 @@ test("validation without a pull request number falls back to the full suite", as
     const repositoryQuality = await readWorkflow("repository-quality.yml");
 
     assert.equal(
-        (entry.match(/\|\| github\.event\.pull_request\.number \|\| 0 \}\}/g) ?? []).length,
+        (entry.match(/\|\| github\.event\.pull_request\.number \|\| 0\)\) \}\}/g) ?? []).length,
         VALIDATION_WORKFLOWS.length,
     );
     for (const gate of ["Require linked Issue"]) {
diff --git a/.github/workflows/pr-validation.yml b/.github/workflows/pr-validation.yml
index 9716a7a..a638ccf 100644
--- a/.github/workflows/pr-validation.yml
+++ b/.github/workflows/pr-validation.yml
@@ -33,12 +33,15 @@ permissions:
   issues: read
   pull-requests: write
 
+# API dispatch로 받은 번호는 문자열일 수 있다. reusable workflow의 number 계약에
+# 맞춰 명시적으로 변환한다. PR 이벤트의 숫자와 번호 없는 경우의 0도 같은 경로를 쓴다.
+# https://docs.github.com/en/actions/reference/workflows-and-actions/expressions#fromjson
 jobs:
   repository-quality:
     name: Repository Quality
     uses: ./.github/workflows/repository-quality.yml
     with:
-      pull_request_number: ${{ inputs.pull_request_number || github.event.pull_request.number || 0 }}
+      pull_request_number: ${{ fromJSON(format('{0}', inputs.pull_request_number || github.event.pull_request.number || 0)) }}
 
   static-analysis:
     name: Static Analysis
@@ -46,7 +49,7 @@ jobs:
     if: ${{ !cancelled() }}
     uses: ./.github/workflows/lint.yml
     with:
-      pull_request_number: ${{ inputs.pull_request_number || github.event.pull_request.number || 0 }}
+      pull_request_number: ${{ fromJSON(format('{0}', inputs.pull_request_number || github.event.pull_request.number || 0)) }}
       run_ktlint: ${{ needs.repository-quality.result != 'success' || needs.repository-quality.outputs.ktlint_required != 'false' }}
       ktlint_tasks: ${{ needs.repository-quality.result == 'success' && needs.repository-quality.outputs.ktlint_tasks || 'ktlintCheck' }}
       run_android_lint: ${{ needs.repository-quality.result != 'success' || needs.repository-quality.outputs.android_lint_required != 'false' }}
@@ -59,7 +62,7 @@ jobs:
     if: ${{ !cancelled() }}
     uses: ./.github/workflows/unit-test.yml
     with:
-      pull_request_number: ${{ inputs.pull_request_number || github.event.pull_request.number || 0 }}
+      pull_request_number: ${{ fromJSON(format('{0}', inputs.pull_request_number || github.event.pull_request.number || 0)) }}
       run_validation: ${{ needs.repository-quality.result != 'success' || needs.repository-quality.outputs.unit_test_required != 'false' }}
       run_node_tests: ${{ needs.repository-quality.result != 'success' || needs.repository-quality.outputs.run_node_tests != 'false' }}
       gradle_tasks: ${{ needs.repository-quality.result == 'success' && needs.repository-quality.outputs.unit_test_tasks || 'testDebugUnitTest :app:compileDebugAndroidTestKotlin' }}
@@ -70,7 +73,7 @@ jobs:
     if: ${{ !cancelled() }}
     uses: ./.github/workflows/screenshot.yml
     with:
-      pull_request_number: ${{ inputs.pull_request_number || github.event.pull_request.number || 0 }}
+      pull_request_number: ${{ fromJSON(format('{0}', inputs.pull_request_number || github.event.pull_request.number || 0)) }}
       run_validation: ${{ needs.repository-quality.result != 'success' || needs.repository-quality.outputs.screenshot_required != 'false' }}
       gradle_tasks: ${{ needs.repository-quality.result == 'success' && needs.repository-quality.outputs.screenshot_tasks || ':app:validateScreenshotTest' }}
       screenshot_modules: ${{ needs.repository-quality.result == 'success' && needs.repository-quality.outputs.screenshot_modules || ':app' }}