From d25c8724d5bda58b068065c6fc446bc62fbb4000 Mon Sep 17 00:00:00 2001
From: Katniss <katnisscalls99@gmail.com>
Date: Fri, 5 Jun 2026 22:29:39 -0700
Subject: [PATCH] fix(openapi): add shebang and chmod +x to gen-mcp generated
 index.js
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generateMcpServer() emits a package.json with a bin entry pointing to
index.js, but the generated index.js starts with a comment line — no
shebang. When the user runs 'npm i -g @generated/foo-mcp' and then
invokes 'foo-mcp' on the shell, the OS tries to exec index.js as a
native script. Without #!/usr/bin/env node it sees 'import' as the first
token and fails with ENOEXEC on Linux or a cryptic syntax error on macOS,
neither of which suggests the real problem.

Two fixes:

1. Prepend '#!/usr/bin/env node' to the generated index template so the
   file is self-describing as a Node.js script.

2. chmod(dest, 0o755) the emitted index.js at write time (only that file,
   not package.json) so 'npm link' / global install symlinks can exec it.
   Uses .catch(() => {}) so the write step doesn't fail on Windows or
   read-only filesystems where the mode change is irrelevant.

The bug affects every MCP server generated by gen-mcp when installed
globally, which is the documented primary use case per the emitted README.
---
 packages/openapi/src/gen-mcp/index.ts | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/packages/openapi/src/gen-mcp/index.ts b/packages/openapi/src/gen-mcp/index.ts
index fcfe3308..69014858 100644
--- a/packages/openapi/src/gen-mcp/index.ts
+++ b/packages/openapi/src/gen-mcp/index.ts
@@ -1,4 +1,4 @@
-import { mkdir, writeFile } from 'node:fs/promises';
+import { mkdir, writeFile, chmod } from 'node:fs/promises';
 import { join } from 'node:path';
 import type { ApiIR, Operation, Parameter } from '../core/types.js';
 
@@ -23,7 +23,15 @@ export async function generateMcpServer(ir: ApiIR, opts: GenerateMcpOptions): Pr
   await mkdir(opts.outDir, { recursive: true });
   for (const f of files) {
     await mkdir(join(opts.outDir, dirOf(f.path)), { recursive: true });
-    await writeFile(join(opts.outDir, f.path), f.contents, 'utf8');
+    const dest = join(opts.outDir, f.path);
+    await writeFile(dest, f.contents, 'utf8');
+    // Make the bin entry executable so `npm i -g` installs a runnable
+    // script. Without 0755, the OS refuses to exec it and the user sees
+    // a confusing EACCES or "import statement" shell error instead of a
+    // running MCP server. Only needed for the entry-point declared in bin.
+    if (f.path === 'index.js') {
+      await chmod(dest, 0o755).catch(() => {});
+    }
   }
   return files;
 }
@@ -35,7 +43,8 @@ function render(ir: ApiIR, opts: GenerateMcpOptions): GeneratedFile[] {
   const tools = ir.operations.map(toolDescriptor).join(',\n');
   const handlers = ir.operations.map(toolHandler).join('\n\n');
 
-  const index = `// AUTO-GENERATED by @profullstack/sh1pt-openapi/gen-mcp.
+  const index = `#!/usr/bin/env node
+// AUTO-GENERATED by @profullstack/sh1pt-openapi/gen-mcp.
 // Source: ${ir.title} v${ir.version}. Do not edit by hand.
 //
 // Stdio MCP server: each upstream API operation is exposed as one tool.