diff --git a/package.json b/package.json
index e738d757d4d0b..09592ea4d6bc8 100644
--- a/package.json
+++ b/package.json
@@ -18,7 +18,7 @@
     "tsc-installer": "tsc -p ./src/install/tsconfig.json",
     "doc": "node utils/doclint/cli.js",
     "test-infra": "node utils/doclint/check_public_api/test/test.js && node utils/doclint/preprocessor/test.js && node utils/testrunner/test/test.js",
-    "lint": "npm run eslint && npm run tsc && npm run doc && npm run check-deps && npm run test-types && npm run test-infra",
+    "lint": "npm run eslint && npm run tsc && npm run doc && npm run check-deps && npm run generate-channels && npm run test-types && npm run test-infra",
     "debug-test": "node --inspect-brk test/test.js",
     "clean": "rimraf lib && rimraf types",
     "prepare": "node install-from-github.js",
@@ -26,6 +26,7 @@
     "watch": "node utils/runWebpack.js --mode='development' --watch --silent | tsc -w -p .",
     "test-types": "npm run generate-types && npx -p typescript@3.7.5 tsc -p utils/generate_types/test/tsconfig.json && npm run typecheck-tests",
     "generate-types": "node utils/generate_types/",
+    "generate-channels": "node utils/generate_channels.js",
     "typecheck-tests": "tsc -p ./test/",
     "roll-browser": "node utils/roll_browser.js",
     "jest": "jest",
diff --git a/src/rpc/channels.ts b/src/rpc/channels.ts
index 0a7dbbbcedae4..f89cb117b74c7 100644
--- a/src/rpc/channels.ts
+++ b/src/rpc/channels.ts
@@ -2034,7 +2034,7 @@ export type RouteAbortParams = {
   errorCode?: string,
 };
 export type RouteAbortOptions = {
-
+  errorCode?: string,
 };
 export type RouteAbortResult = void;
 export type RouteContinueParams = {
@@ -2064,7 +2064,13 @@ export type RouteFulfillParams = {
   isBase64?: boolean,
 };
 export type RouteFulfillOptions = {
-
+  status?: number,
+  headers?: {
+    name: string,
+    value: string,
+  }[],
+  body?: string,
+  isBase64?: boolean,
 };
 export type RouteFulfillResult = void;
 
diff --git a/utils/generate_channels.js b/utils/generate_channels.js
index aecf1b792fadf..d70dacad95a00 100755
--- a/utils/generate_channels.js
+++ b/utils/generate_channels.js
@@ -229,5 +229,18 @@ validator_ts.push(`
 }
 `);
 
-fs.writeFileSync(path.join(__dirname, '..', 'src', 'rpc', 'channels.ts'), channels_ts.join('\n'), 'utf-8');
-fs.writeFileSync(path.join(__dirname, '..', 'src', 'rpc', 'validator.ts'), validator_ts.join('\n'), 'utf-8');
+let hasChanges = false;
+
+function writeFile(filePath, content) {
+  const existing = fs.readFileSync(filePath, 'utf8');
+  if (existing === content)
+    return;
+  hasChanges = true;
+  const root = path.join(__dirname, '..');
+  console.log(`Writing //${path.relative(root, filePath)}`);
+  fs.writeFileSync(filePath, content, 'utf8');
+}
+
+writeFile(path.join(__dirname, '..', 'src', 'rpc', 'channels.ts'), channels_ts.join('\n'));
+writeFile(path.join(__dirname, '..', 'src', 'rpc', 'validator.ts'), validator_ts.join('\n'));
+process.exit(hasChanges ? 1 : 0);