diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index b627534..dec7707 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -139,6 +139,8 @@ jobs:
   release-server:
     needs: [preflight, release-extension-draft]
     runs-on: ubuntu-latest
+    env:
+      IMAGE: ghcr.io/shik3i/koalasync
     permissions:
       contents: read
       packages: write
@@ -162,7 +164,7 @@ jobs:
         id: meta
         uses: docker/metadata-action@v6
         with:
-          images: ghcr.io/${{ github.repository }}
+          images: ${{ env.IMAGE }}
           tags: |
             type=raw,value=latest
             type=ref,event=tag
@@ -183,14 +185,13 @@ jobs:
       - name: Attest relay image
         uses: actions/attest@v4
         with:
-          subject-name: ghcr.io/${{ github.repository }}
+          subject-name: ${{ env.IMAGE }}
           subject-digest: ${{ steps.build.outputs.digest }}
           push-to-registry: true
 
       - name: Verify manifest, provenance, and running image
         env:
           DIGEST: ${{ steps.build.outputs.digest }}
-          IMAGE: ghcr.io/${{ github.repository }}
           SOURCE_DIGEST: ${{ needs.preflight.outputs.tag-commit }}
           GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         run: |
diff --git a/AGENTS.md b/AGENTS.md
index d73d95d..82d20e3 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -17,6 +17,9 @@ These rules are mandatory for every automated agent working in this repository.
   `linux/amd64`, Ubuntu Noble, and `CI=1`; it must run clean installs, full
   verification, all browser E2E tests, the relay image build, and health smoke.
 - A failed, interrupted, ARM64, skipped, or partial run is not a passing gate.
+- All OCI image references must use the canonical lowercase
+  `ghcr.io/shik3i/koalasync`; never construct Docker references from the
+  case-preserving `${{ github.repository }}` value. The local gate enforces this.
 - Do not say "release-ready" until the candidate gate and PR required checks
   are green for the exact commit.
 
diff --git a/docs/devops.md b/docs/devops.md
index b27c63c..81ff77a 100644
--- a/docs/devops.md
+++ b/docs/devops.md
@@ -81,3 +81,8 @@ the public GitHub assets and GHCR digest before calling the release complete.
 `release:gate`. The gate pins the official Playwright image to the exact
 lockfile version and forces `linux/amd64`, matching GitHub's Ubuntu runner even
 when the developer host is macOS or ARM64.
+
+The relay registry reference is always the canonical lowercase
+`ghcr.io/shik3i/koalasync`. Docker repository names reject uppercase characters;
+`release:gate` rejects workflows that derive this reference from the
+case-preserving `${{ github.repository }}` value.
diff --git a/scripts/release-local-gate.mjs b/scripts/release-local-gate.mjs
index e755b14..e978a93 100644
--- a/scripts/release-local-gate.mjs
+++ b/scripts/release-local-gate.mjs
@@ -64,6 +64,21 @@ export function parseRemoteMain(text) {
     return match[1];
 }
 
+export function validateReleaseWorkflowContract(text) {
+    const workflow = String(text);
+    const image = 'ghcr.io/shik3i/koalasync';
+    if (!workflow.includes(`IMAGE: ${image}`)) {
+        throw new Error(`release workflow must define the lowercase canonical image ${image}`);
+    }
+    for (const reference of ['images: ${{ env.IMAGE }}', 'subject-name: ${{ env.IMAGE }}']) {
+        if (!workflow.includes(reference)) throw new Error(`release workflow must use ${reference}`);
+    }
+    if (/ghcr\.io\/\$\{\{\s*github\.repository\s*\}\}/u.test(workflow)) {
+        throw new Error('release workflow must not derive a Docker image from case-preserving github.repository');
+    }
+    return image;
+}
+
 function assertCleanTree() {
     const status = capture('git', ['status', '--porcelain=v1']);
     if (status) throw new Error(`release gate requires a clean working tree:\n${status}`);
@@ -120,6 +135,9 @@ async function smokeRelayImage(image) {
 export async function runReleaseGate({ version, candidate }) {
     assertCleanTree();
     validateReleaseSourceVersion(version, repoRoot);
+    validateReleaseWorkflowContract(fs.readFileSync(
+        path.join(repoRoot, '.github/workflows/release.yml'), 'utf8'
+    ));
     if (!candidate) assertFinalMainChecks();
 
     const lock = JSON.parse(fs.readFileSync(path.join(repoRoot, 'package-lock.json'), 'utf8'));
diff --git a/scripts/release-local-gate.test.mjs b/scripts/release-local-gate.test.mjs
index 1eadb23..82836b5 100644
--- a/scripts/release-local-gate.test.mjs
+++ b/scripts/release-local-gate.test.mjs
@@ -3,7 +3,8 @@ import {
     linuxGateCommand,
     parseGateArgs,
     parseRemoteMain,
-    playwrightImageFromLock
+    playwrightImageFromLock,
+    validateReleaseWorkflowContract
 } from './release-local-gate.mjs';
 
 describe('local release gate contract', () => {
@@ -28,6 +29,21 @@ describe('local release gate contract', () => {
         expect(() => parseRemoteMain(`${sha}\trefs/heads/not-main`)).toThrow('could not resolve origin main');
     });
 
+    it('requires one lowercase registry image throughout the release workflow', () => {
+        const valid = [
+            'IMAGE: ghcr.io/shik3i/koalasync',
+            'images: ${{ env.IMAGE }}',
+            'subject-name: ${{ env.IMAGE }}'
+        ].join('\n');
+        expect(validateReleaseWorkflowContract(valid)).toBe('ghcr.io/shik3i/koalasync');
+        expect(() => validateReleaseWorkflowContract(valid.replace(
+            'IMAGE: ghcr.io/shik3i/koalasync',
+            'IMAGE: ghcr.io/${{ github.repository }}'
+        ))).toThrow('lowercase canonical image');
+        expect(() => validateReleaseWorkflowContract(`${valid}\n${'ghcr.io/${{ github.repository }}'}`))
+            .toThrow('case-preserving github.repository');
+    });
+
     it('runs the complete CI-equivalent dependency, verify, and browser sequence', () => {
         expect(linuxGateCommand()).toBe([
             'git clone --no-local /src /work',