diff --git a/packages/fs/src/index.ts b/packages/fs/src/index.ts
index fc44c8c..a0531d4 100644
--- a/packages/fs/src/index.ts
+++ b/packages/fs/src/index.ts
@@ -8,23 +8,26 @@ import fs from 'fs';
 
 export function main(_argv: string[]) {
     service(args => {
-        const config = asConfig(args);
-        at config.dataspace {
-            during Observe({
-                "pattern": :pattern File({
-                    "label": config.label,
-                    "path": \Q.lit($relativePath: string),
-                    "encoding": \Q.lit($encoding0),
-                    "contents": \_,
-                }),
-            }) => {
-                const encoding = toEncoding(encoding0);
-                if (encoding !== void 0 && !path.isAbsolute(relativePath)) {
-                    trackFile(config, relativePath, encoding);
-                }
+        serve(asConfig(args));
+    });
+}
+
+export function serve(config: Config<Ref>) {
+    at config.dataspace {
+        during Observe({
+            "pattern": :pattern File({
+                "label": config.label,
+                "path": \Q.lit($relativePath: string),
+                "encoding": \Q.lit($encoding0),
+                "contents": \_,
+            }),
+        }) => {
+            const encoding = toEncoding(encoding0);
+            if (encoding !== void 0 && !path.isAbsolute(relativePath)) {
+                trackFile(config, relativePath, encoding);
             }
         }
-    });
+    }
 }
 
 function trackFile(config: Config<Ref>, relativePath: string, encoding: Encoding) {