diff --git a/packages/core/src/__tests__/permissions-integration.test.ts b/packages/core/src/__tests__/permissions-integration.test.ts
index 7d340d8..342389f 100644
--- a/packages/core/src/__tests__/permissions-integration.test.ts
+++ b/packages/core/src/__tests__/permissions-integration.test.ts
@@ -662,6 +662,39 @@ describe('WorkflowRunner permission lifecycle integration', () => {
     expect((runner as any).agentTokens.size).toBe(0);
   });
 
+  it('warns when a write pattern resolves to no existing paths during dry-run', () => {
+    const projectDir = createProject({
+      'src/input.ts': 'export const input = true;\n',
+      'gate.sh': '#!/usr/bin/env bash\nexit 0\n',
+    });
+    const runner = makeRunner(projectDir);
+    const config = makeConfig([
+      {
+        name: 'writer',
+        cli: 'claude',
+        permissions: {
+          access: 'restricted',
+          files: {
+            read: ['**'],
+            write: ['impl.txt'],
+            deny: ['gate.sh'],
+          },
+        },
+      },
+    ]);
+
+    const report = runner.dryRun(config, 'default');
+    const permissionEntry = report.permissions?.find((entry) => entry.agent === 'writer');
+
+    expect(report.valid).toBe(true);
+    expect(permissionEntry?.writePaths).toBe(0);
+    expect(report.warnings).toContain(
+      'Agent "writer" write pattern(s) "impl.txt" resolved to no existing writable paths. '
+        + 'The installed @agent-relay/cloud resolver only grants writes to existing paths; '
+        + 'files created under these patterns may be denied.'
+    );
+  });
+
   it('rejects invalid permission config during validation before provisioning', async () => {
     const projectDir = createBaseProject();
     const runner = makeRunner(projectDir);
diff --git a/packages/core/src/runner.ts b/packages/core/src/runner.ts
index ee17545..f8c9b88 100644
--- a/packages/core/src/runner.ts
+++ b/packages/core/src/runner.ts
@@ -3080,6 +3080,14 @@ export class WorkflowRunner {
 
     const permissions = resolved.agents.map((agent) => {
       const compiled = resolveAgentPermissions(agent.name, agent.permissions, this.cwd, this.workspaceId);
+      if (compiled.readwritePatterns.length > 0 && compiled.summary.readwrite === 0) {
+        const patterns = compiled.readwritePatterns.map((pattern) => `"${pattern}"`).join(', ');
+        warnings.push(
+          `Agent "${agent.name}" write pattern(s) ${patterns} resolved to no existing writable paths. ` +
+            'The installed @agent-relay/cloud resolver only grants writes to existing paths; ' +
+            'files created under these patterns may be denied.'
+        );
+      }
       const source: NonNullable<DryRunReport['permissions']>[number]['source'] = compiled.sources.some(
         (entry) => entry.type === 'yaml'
       )