diff --git a/src/actions-util.ts b/src/actions-util.ts
index 096bdd8f1..abd29a052 100644
--- a/src/actions-util.ts
+++ b/src/actions-util.ts
@@ -364,7 +364,7 @@ const MAX_STDERR_BUFFER_SIZE = 20000;
  * @throws A {@link CommandInvocationError} if the tool exits with a non-zero status code.
  */
 export async function runTool(
-  env: Env,
+  env: ReadOnlyEnv,
   cmd: string,
   args: string[] = [],
   opts: { stdin?: string; noStreamStdout?: boolean } = {},
diff --git a/src/codeql.ts b/src/codeql.ts
index 8f2d9843e..ca93cedf1 100644
--- a/src/codeql.ts
+++ b/src/codeql.ts
@@ -1166,7 +1166,7 @@ export function getExtraOptions(
 }
 
 async function runCli(
-  env: Env,
+  env: ReadOnlyEnv,
   cmd: string,
   args: string[] = [],
   opts: { stdin?: string; noStreamStdout?: boolean } = {},
@@ -1193,7 +1193,7 @@ async function runCli(
  * @returns The parsed JSON output from the command.
  */
 async function runCliJson<T>(
-  env: Env,
+  env: ReadOnlyEnv,
   cmd: string,
   args: string[] = [],
   opts: { stdin?: string; noStreamStdout?: boolean } = {},