diff --git a/.gitignore b/.gitignore
index 0d2c97c..ccf6c39 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,3 +15,5 @@ node_modules/
 /test_artifacts/
 /coverage/
 yarn-error.log
+/hak/**/*.js
+/scripts/hak/**/*.js
diff --git a/hak/matrix-seshat/check.ts b/hak/matrix-seshat/check.ts
index 86e1112..759e7f3 100644
--- a/hak/matrix-seshat/check.ts
+++ b/hak/matrix-seshat/check.ts
@@ -80,7 +80,7 @@ export default async function(hakEnv: HakEnv, moduleInfo: DependencyInfo): Promi
             }
             fsProm.unlink('tmp').then(resolve);
         });
-        rustc.stdin.write('fn main() {}');
-        rustc.stdin.end();
+        rustc.stdin!.write('fn main() {}');
+        rustc.stdin!.end();
     });
 }
diff --git a/hak/tsconfig.json b/hak/tsconfig.json
index 46abbda..5a3b17a 100644
--- a/hak/tsconfig.json
+++ b/hak/tsconfig.json
@@ -4,11 +4,13 @@
     "esModuleInterop": true,
     "target": "es2016",
     "sourceMap": false,
+    "strict": true,
     "lib": [
       "es2019",
     ]
   },
   "include": [
+    "../scripts/@types/*.d.ts",
     "./**/*.ts"
   ],
   "ts-node": {
diff --git a/scripts/hak/find-npm-prefix.d.ts b/scripts/@types/find-npm-prefix.d.ts
similarity index 100%
rename from scripts/hak/find-npm-prefix.d.ts
rename to scripts/@types/find-npm-prefix.d.ts
diff --git a/scripts/hak/node-pre-gyp.d.ts b/scripts/@types/node-pre-gyp.d.ts
similarity index 100%
rename from scripts/hak/node-pre-gyp.d.ts
rename to scripts/@types/node-pre-gyp.d.ts