diff --git a/packages/openapi-ts/src/generate/__tests__/renderer-placeholders.test.ts b/packages/openapi-ts/src/generate/__tests__/renderer-placeholders.test.ts
new file mode 100644
index 000000000..e08910df1
--- /dev/null
+++ b/packages/openapi-ts/src/generate/__tests__/renderer-placeholders.test.ts
@@ -0,0 +1,122 @@
+import { describe, expect, it } from 'vitest';
+
+import { TypeScriptRenderer } from '../renderer';
+
+// Minimal local BiMap for tests
+class LocalBiMap<Key, Value> {
+  private map = new Map<Key, Value>();
+  private reverse = new Map<Value, Key>();
+  get(key: Key) {
+    return this.map.get(key);
+  }
+  getKey(value: Value) {
+    return this.reverse.get(value);
+  }
+  set(key: Key, value: Value) {
+    this.map.set(key, value);
+    this.reverse.set(value, key);
+    return this;
+  }
+  hasValue(value: Value) {
+    return this.reverse.has(value);
+  }
+}
+
+describe('TypeScriptRenderer - Placeholder Replacement', () => {
+  it('should replace placeholders in external symbol references', () => {
+    const renderer = new TypeScriptRenderer();
+
+    const symbolId = 1;
+    const symbol = {
+      external: 'zod',
+      id: symbolId,
+      kind: undefined,
+      meta: { category: 'external', resource: 'zod.z' },
+      name: 'z',
+      placeholder: '_heyapi_1_',
+    };
+
+    const project = {
+      symbolIdToFiles: () => [],
+      symbols: new Map([[symbolId, symbol]]),
+    } as any;
+
+    const file: any = {
+      resolvedNames: new LocalBiMap<number, string>(),
+    };
+
+    // Simulate rendering content with a placeholder
+    const content = `export const schema = ${symbol.placeholder}.object({});`;
+
+    // This is what renderFile does internally
+    const processed = content.replace(/_heyapi_(\d+)_/g, (match) => {
+      const id = Number.parseInt(match.slice('_heyapi_'.length, -1), 10);
+      const sym = project.symbols.get(id);
+      const result = renderer['replacerFn']({ file, project, symbol: sym });
+      return result || match;
+    });
+
+    expect(processed).toBe('export const schema = z.object({});');
+  });
+
+  it('should handle stub symbols that are later registered', () => {
+    const renderer = new TypeScriptRenderer();
+
+    // First, create a stub (symbol without name)
+    const stubId = 1;
+    const stub = {
+      exportFrom: [],
+      external: 'zod',
+      id: stubId,
+      meta: { category: 'external', resource: 'zod.z' },
+      placeholder: '_heyapi_1_',
+      // Note: no 'name' property!
+    };
+
+    const project = {
+      symbolIdToFiles: () => [],
+      symbols: new Map([[stubId, stub]]),
+    } as any;
+
+    const file: any = {
+      resolvedNames: new LocalBiMap<number, string>(),
+    };
+
+    // Try to replace placeholder with stub
+    const result = renderer['replacerFn']({ file, project, symbol: stub });
+
+    // With the fix: replacerFn now derives the name from the resource
+    // even if stub.name is undefined
+    expect(result).toBe('z');
+  });
+
+  it('should handle external symbols without names by using resource', () => {
+    const renderer = new TypeScriptRenderer();
+
+    const symbolId = 1;
+    const symbol = {
+      exportFrom: [],
+      external: 'zod',
+      id: symbolId,
+      meta: { category: 'external', resource: 'zod.z' },
+      placeholder: '_heyapi_1_',
+      // Note: no 'name' property, but has 'external' and 'meta.resource'
+    };
+
+    const project = {
+      symbolIdToFiles: () => [],
+      symbols: new Map([[symbolId, symbol]]),
+    } as any;
+
+    const file: any = {
+      resolvedNames: new LocalBiMap<number, string>(),
+    };
+
+    // This test documents the expected behavior:
+    // When a symbol has no name but has external+resource, we should derive the name
+    const result = renderer['replacerFn']({ file, project, symbol });
+
+    // With the fix: derives the name from the resource 'zod.z' → 'z'
+    expect(result).toBe('z');
+  });
+});
diff --git a/packages/openapi-ts/src/generate/renderer.ts b/packages/openapi-ts/src/generate/renderer.ts
index aa976eb5e..a07323cb3 100644
--- a/packages/openapi-ts/src/generate/renderer.ts
+++ b/packages/openapi-ts/src/generate/renderer.ts
@@ -475,10 +475,22 @@ export class TypeScriptRenderer implements Renderer {
     if (!symbol) return;
     const cached = file.resolvedNames.get(symbol.id);
     if (cached) return cached;
-    if (!symbol.name) return;
+
+    // Handle symbols without a name by deriving it from the resource
+    let symbolName = symbol.name;
+    if (!symbolName && symbol.meta?.resource) {
+      // For external symbols like 'zod.z', extract the last part as the name
+      const resource = symbol.meta.resource;
+      if (typeof resource === 'string') {
+        const parts = resource.split('.');
+        symbolName = parts[parts.length - 1];
+      }
+    }
+
+    if (!symbolName) return;
     const [symbolFile] = project.symbolIdToFiles(symbol.id);
     const symbolFileResolvedName = symbolFile?.resolvedNames.get(symbol.id);
-    let name = ensureValidIdentifier(symbolFileResolvedName ?? symbol.name);
+    let name = ensureValidIdentifier(symbolFileResolvedName ?? symbolName);
     const conflictId = file.resolvedNames.getKey(name);
     if (conflictId !== undefined) {
       const conflictSymbol = project.symbols.get(conflictId);