diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5c112e27..23d77818 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,6 @@
 # Changelog
 
+- **Fixed** Missing env vars requested through `@voidzero-dev/vite-task-client` now return `undefined` instead of `null`, preserving Vite production `NODE_ENV` semantics when builds run through `vp run` ([#508](https://github.com/voidzero-dev/vite-task/pull/508)).
 - **Fixed** Windows builds no longer hang on CI when a `node_modules/.bin` `.cmd` shim is routed through PowerShell: the npm/pnpm/yarn `.ps1` wrappers read stdin and block forever on a non-TTY pipe, so the PowerShell rewrite is now skipped when stdin is not an interactive terminal, falling back to the `.cmd` (which never reads stdin) ([#491](https://github.com/voidzero-dev/vite-task/pull/491)).
 - **Added** First-party support for caching `vite build` with zero cache config, giving Vite projects correct cache hits out of the box ([vitejs/vite#22453](https://github.com/vitejs/vite/pull/22453)).
 - **Added** Support for specifying tasks from dependency packages in `dependsOn`, such as `dependsOn: [{ "task": "build", "from": "dependencies" }]` ([#479](https://github.com/voidzero-dev/vite-task/pull/479)).
diff --git a/crates/vite_task_bin/tests/e2e_snapshots/fixtures/ipc_client_test/scripts/assert_undefined_env.mjs b/crates/vite_task_bin/tests/e2e_snapshots/fixtures/ipc_client_test/scripts/assert_undefined_env.mjs
new file mode 100644
index 00000000..c1549ae8
--- /dev/null
+++ b/crates/vite_task_bin/tests/e2e_snapshots/fixtures/ipc_client_test/scripts/assert_undefined_env.mjs
@@ -0,0 +1,10 @@
+import { getEnv } from '@voidzero-dev/vite-task-client';
+
+const name = '__VITE_TASK_CLIENT_MISSING_ENV__';
+const value = getEnv(name);
+
+if (value !== undefined) {
+  throw new Error(`expected ${name} to be undefined, got ${value}`);
+}
+
+console.log('missing undefined');
diff --git a/crates/vite_task_bin/tests/e2e_snapshots/fixtures/ipc_client_test/snapshots.toml b/crates/vite_task_bin/tests/e2e_snapshots/fixtures/ipc_client_test/snapshots.toml
index 7d27979a..64f809c2 100644
--- a/crates/vite_task_bin/tests/e2e_snapshots/fixtures/ipc_client_test/snapshots.toml
+++ b/crates/vite_task_bin/tests/e2e_snapshots/fixtures/ipc_client_test/snapshots.toml
@@ -276,6 +276,20 @@ steps = [
   ], comment = "summary reports the replayed cache hit" },
 ]
 
+[[e2e]]
+name = "fetch_env_missing_returns_undefined"
+comment = """
+Exercises the public `getEnv(name)` contract for an absent env var. The client API must expose `undefined` so callers can distinguish absence using the documented API.
+"""
+ignore = true
+steps = [
+  { argv = [
+    "vt",
+    "run",
+    "fetch-missing-env",
+  ], comment = "missing env values are normalized to undefined" },
+]
+
 [[e2e]]
 name = "fetch_env_reads_undeclared_env"
 comment = """
diff --git a/crates/vite_task_bin/tests/e2e_snapshots/fixtures/ipc_client_test/snapshots/fetch_env_missing_returns_undefined.md b/crates/vite_task_bin/tests/e2e_snapshots/fixtures/ipc_client_test/snapshots/fetch_env_missing_returns_undefined.md
new file mode 100644
index 00000000..ef6d4c5f
--- /dev/null
+++ b/crates/vite_task_bin/tests/e2e_snapshots/fixtures/ipc_client_test/snapshots/fetch_env_missing_returns_undefined.md
@@ -0,0 +1,12 @@
+# fetch_env_missing_returns_undefined
+
+Exercises the public `getEnv(name)` contract for an absent env var. The client API must expose `undefined` so callers can distinguish absence using the documented API.
+
+## `vt run fetch-missing-env`
+
+missing env values are normalized to undefined
+
+```
+$ node scripts/assert_undefined_env.mjs
+missing undefined
+```
diff --git a/crates/vite_task_bin/tests/e2e_snapshots/fixtures/ipc_client_test/vite-task.json b/crates/vite_task_bin/tests/e2e_snapshots/fixtures/ipc_client_test/vite-task.json
index dbbdfeb7..4f00c3ce 100644
--- a/crates/vite_task_bin/tests/e2e_snapshots/fixtures/ipc_client_test/vite-task.json
+++ b/crates/vite_task_bin/tests/e2e_snapshots/fixtures/ipc_client_test/vite-task.json
@@ -58,6 +58,10 @@
       "command": "node scripts/fetch_env.mjs PROBE_ENV",
       "cache": true
     },
+    "fetch-missing-env": {
+      "command": "node scripts/assert_undefined_env.mjs",
+      "cache": true
+    },
     "fetch-env-explicit-input": {
       "command": "node scripts/fetch_env.mjs PROBE_ENV",
       "input": [],
diff --git a/crates/vite_task_client_napi/src/lib.rs b/crates/vite_task_client_napi/src/lib.rs
index 81f4a005..72e170c3 100644
--- a/crates/vite_task_client_napi/src/lib.rs
+++ b/crates/vite_task_client_napi/src/lib.rs
@@ -30,7 +30,7 @@
 )]
 use std::{collections::HashMap, ffi::OsStr};
 
-use napi::{Either, Error, Result};
+use napi::{Either, Error, Result, bindgen_prelude::Undefined};
 use napi_derive::napi;
 use vite_task_client::{Client, GetEnvsQuery};
 
@@ -85,17 +85,24 @@ impl RunnerClient {
     }
 
     #[napi]
-    pub fn get_env(&self, name: String, options: Option<GetEnvOptions>) -> Result<Option<String>> {
+    pub fn get_env(
+        &self,
+        name: String,
+        options: Option<GetEnvOptions>,
+    ) -> Result<Either<String, Undefined>> {
         let tracked = options.and_then(|o| o.tracked).unwrap_or(true);
         let value = self
             .client
             .get_env(OsStr::new(&name), tracked)
             .map_err(|err| err_string(vite_str::format!("{err}")))?;
-        value.map_or(Ok(None), |value| {
-            value.to_str().map(|s| Some(s.to_owned())).ok_or_else(|| {
-                err_string(vite_str::format!("env value for {name} is not valid UTF-8"))
+        let value = value
+            .map(|value| {
+                value.to_str().map(str::to_owned).ok_or_else(|| {
+                    err_string(vite_str::format!("env value for {name} is not valid UTF-8"))
+                })
             })
-        })
+            .transpose()?;
+        Ok(value.into())
     }
 
     #[napi]