diff --git a/packages/cli/src/utils/externals-generator.ts b/packages/cli/src/utils/externals-generator.ts
index 48f3262..4821d93 100644
--- a/packages/cli/src/utils/externals-generator.ts
+++ b/packages/cli/src/utils/externals-generator.ts
@@ -22,12 +22,12 @@ function getNamespacePrefix(pattern: string): string {
 /**
  * Generate TypeSpec external definitions from lexicon documents
  */
-function generateExternalsCode(lexicons: Map<string, LexiconDoc>): string {
+function generateExternalsCode(lexicons: Map<string, LexiconDoc>, outDir: string, excludedPrefix: string): string {
   const lines: string[] = [];
 
   lines.push('import "@typelex/emitter";');
   lines.push("");
-  lines.push("// Generated by typelex");
+  lines.push(`// Generated by typelex from ${outDir} (excluding ${excludedPrefix}.*)`);
   lines.push("// This file is auto-generated. Do not edit manually.");
   lines.push("");
 
@@ -89,13 +89,13 @@ export async function generateExternalsFile(
       await mkdir(resolve(cwd, "typelex"), { recursive: true });
       await writeFile(
         outputFile,
-        'import "@typelex/emitter";\n\n// Generated by typelex\n// No external lexicons found\n',
+        `import "@typelex/emitter";\n\n// Generated by typelex from ${outDir} (excluding ${prefix}.*)\n// No external lexicons found\n`,
         "utf-8"
       );
       return;
     }
 
-    const code = generateExternalsCode(externals);
+    const code = generateExternalsCode(externals, outDir, prefix);
     await mkdir(resolve(cwd, "typelex"), { recursive: true });
     await writeFile(outputFile, code, "utf-8");
   } catch (error) {
diff --git a/packages/example/typelex/externals.tsp b/packages/example/typelex/externals.tsp
index e25e47d..61b81c2 100644
--- a/packages/example/typelex/externals.tsp
+++ b/packages/example/typelex/externals.tsp
@@ -1,6 +1,6 @@
 import "@typelex/emitter";
 
-// Generated by typelex
+// Generated by typelex from ./lexicons (excluding xyz.statusphere.*)
 // This file is auto-generated. Do not edit manually.
 
 @external