diff --git a/@packages/model-boss-mcp/tsup.config.ts b/@packages/model-boss-mcp/tsup.config.ts
index 34e1a97..eea13cf 100644
--- a/@packages/model-boss-mcp/tsup.config.ts
+++ b/@packages/model-boss-mcp/tsup.config.ts
@@ -35,12 +35,17 @@ export default defineConfig({
           };
         });
 
-        // ajv-formats requires ajv v8 deep paths (ajv/dist/compile/codegen).
-        // The workspace has ajv v6 which doesn't have this structure.
-        // The MCP SDK loads ajv validation lazily and this server never uses it,
-        // so mark these deep requires as external (they'll never be called at runtime).
-        build.onResolve({ filter: /^ajv\/dist\// }, () => {
-          return { path: 'ajv/dist/compile/codegen', external: true };
+        // ajv-formats requires ajv v8 (ajv/dist/compile/codegen) which isn't
+        // installed. The MCP SDK loads ajv validation lazily and this server
+        // never invokes it. Stub ajv-formats entirely.
+        build.onResolve({ filter: /^ajv-formats/ }, (args) => {
+          return { path: args.path, namespace: 'ajv-stub' };
+        });
+        build.onResolve({ filter: /^ajv\/dist\// }, (args) => {
+          return { path: args.path, namespace: 'ajv-stub' };
+        });
+        build.onLoad({ filter: /.*/, namespace: 'ajv-stub' }, () => {
+          return { contents: 'module.exports = function() {};', loader: 'js' };
         });
       },
     },