fix(mcp-npm): v0.1.1 skip npm shim when resolving Go binary

npx installs a bin also named opsxdb-mcp; the launcher now only execs
native ELF/Mach-O/PE binaries so it no longer recurses into itself.

packages/opsxdb-mcp/README.md

@@ -2,14 +2,16 @@
 
 MCP (Model Context Protocol) launcher for OpsxDB.
 
-This package ships a small Node CLI that **spawns the Go `opsxdb-mcp` binary** over stdio. Build the binary from the OpsxDB repo, then point the launcher at it.
+This package ships a small Node CLI that **spawns the Go `opsxdb-mcp` binary** over stdio. Build the binary from the OpsxDB repo, then point the launcher at it (or put the Go binary on `PATH`).
+
+> The npm bin is also named `opsxdb-mcp`. The launcher only execs a **native** Go/ELF/Mach-O/PE binary, so it will not recurse into its own npm shim.
 
 ## Install
 
 ```bash
 npm i -g @rlwj-lab/opsxdb-mcp
 # or
-npx -y @rlwj-lab/opsxdb-mcp
+npx -y @rlwj-lab/opsxdb-mcp@0.1.1
 ```
 
 ## Build the Go binary
@@ -26,6 +28,8 @@ Put `bin/opsxdb-mcp` on `PATH`, or set:
 export OPSXDB_MCP_BIN=/absolute/path/to/opsxdb-mcp
 ```
 
+If the Go binary is missing, the CLI exits with a clear error (not `command not found`).
+
 ## Cursor / Claude Desktop
 
 ```json

packages/opsxdb-mcp/dist/resolve-binary.js

@@ -7,11 +7,16 @@ const os = require('os');
 /**
  * Resolve the OpsxDB Go MCP binary path.
  * Order: OPSXDB_MCP_BIN → PATH → common install locations.
+ * Skips this package's Node launcher and any #! script shims (npm/npx bin
+ * is also named opsxdb-mcp and must not be mistaken for the Go server).
  * @returns {string|null}
  */
 function resolveBinary() {
   const envBin = process.env.OPSXDB_MCP_BIN;
-  if (envBin && isExecutable(envBin)) return path.resolve(envBin);
+  if (envBin) {
+    const resolved = path.resolve(envBin);
+    if (isGoMcpBinary(resolved)) return resolved;
+  }
 
   const onPath = findOnPath('opsxdb-mcp');
   if (onPath) return onPath;
@@ -25,7 +30,7 @@ function resolveBinary() {
     '/opt/homebrew/bin/opsxdb-mcp',
   ];
   for (const c of candidates) {
-    if (isExecutable(c)) return c;
+    if (isGoMcpBinary(c)) return c;
   }
   return null;
 }
@@ -35,16 +40,38 @@ function findOnPath(name) {
   for (const dir of pathEnv.split(path.delimiter)) {
     if (!dir) continue;
     const p = path.join(dir, name);
-    if (isExecutable(p)) return p;
-    if (process.platform === 'win32' && isExecutable(p + '.exe')) return p + '.exe';
+    if (isGoMcpBinary(p)) return p;
+    if (process.platform === 'win32') {
+      const pe = p + '.exe';
+      if (isGoMcpBinary(pe)) return pe;
+    }
   }
   return null;
 }
 
-function isExecutable(filePath) {
+function selfCliPath() {
+  return path.resolve(__dirname, '..', 'bin', 'cli.js');
+}
+
+function isSameFile(a, b) {
   try {
+    return fs.realpathSync(a) === fs.realpathSync(b);
+  } catch {
+    return false;
+  }
+}
+
+/**
+ * True only for a real Go/native opsxdb-mcp binary (ELF / Mach-O / PE),
+ * not npm bin shims or this package's Node cli.js.
+ */
+function isGoMcpBinary(filePath) {
+  try {
+    if (!filePath) return false;
     const st = fs.statSync(filePath);
     if (!st.isFile()) return false;
+    if (isSameFile(filePath, selfCliPath())) return false;
+    if (!isLikelyNativeBinary(filePath)) return false;
     fs.accessSync(filePath, fs.constants.X_OK);
     return true;
   } catch {
@@ -52,6 +79,44 @@ function isExecutable(filePath) {
   }
 }
 
+function isLikelyNativeBinary(filePath) {
+  let fd;
+  try {
+    fd = fs.openSync(filePath, 'r');
+    const buf = Buffer.alloc(8);
+    const n = fs.readSync(fd, buf, 0, 8, 0);
+    if (n < 2) return false;
+    // Reject scripts (npm shims, node shebang)
+    if (buf[0] === 0x23 && buf[1] === 0x21) return false; // #!
+    // ELF
+    if (n >= 4 && buf[0] === 0x7f && buf[1] === 0x45 && buf[2] === 0x4c && buf[3] === 0x46) {
+      return true;
+    }
+    // PE
+    if (buf[0] === 0x4d && buf[1] === 0x5a) return true;
+    if (n < 4) return false;
+    const be = buf.readUInt32BE(0);
+    const le = buf.readUInt32LE(0);
+    // Mach-O 64 / 32 (both endians) + fat
+    const macho = new Set([
+      0xfeedfacf, 0xcffaedfe, 0xfeedface, 0xcefaedfe,
+      0xcafebabe, 0xbebafeca, 0xcafebabf, 0xbfbafeca,
+    ]);
+    if (macho.has(be) || macho.has(le)) return true;
+    return false;
+  } catch {
+    return false;
+  } finally {
+    if (fd !== undefined) {
+      try {
+        fs.closeSync(fd);
+      } catch {
+        /* ignore */
+      }
+    }
+  }
+}
+
 function missingBinaryMessage() {
   return `opsxdb-mcp: Go binary not found.
 
@@ -63,7 +128,7 @@ Build it from the opsxdb repo:
   cd server && go build -o ../bin/opsxdb-mcp ./cmd/opsxdb-mcp
 
 Then either:
-  - put bin/opsxdb-mcp on your PATH, or
+  - put that binary on your PATH (ahead of any npm shim), or
   - export OPSXDB_MCP_BIN=/absolute/path/to/opsxdb-mcp
 
 Cursor / Claude Desktop example:
@@ -89,4 +154,5 @@ Config files (same as native binary):
 module.exports = {
   resolveBinary,
   missingBinaryMessage,
+  isGoMcpBinary,
 };

packages/opsxdb-mcp/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@rlwj-lab/opsxdb-mcp",
-  "version": "0.1.0",
+  "version": "0.1.1",
   "description": "MCP server for opsxdb",
   "main": "index.js",
   "bin": {