diff --git a/crates/vite_task_plan/tests/plan_snapshots/fixtures/pnpm-workspace-packages-optional/package.json b/crates/vite_task_plan/tests/plan_snapshots/fixtures/pnpm-workspace-packages-optional/package.json
new file mode 100644
index 00000000..a3f69d92
--- /dev/null
+++ b/crates/vite_task_plan/tests/plan_snapshots/fixtures/pnpm-workspace-packages-optional/package.json
@@ -0,0 +1,7 @@
+{
+  "name": "additional-envs",
+  "private": true,
+  "scripts": {
+    "hello": "echo hello"
+  }
+}
diff --git a/crates/vite_task_plan/tests/plan_snapshots/fixtures/pnpm-workspace-packages-optional/pnpm-workspace.yaml b/crates/vite_task_plan/tests/plan_snapshots/fixtures/pnpm-workspace-packages-optional/pnpm-workspace.yaml
new file mode 100644
index 00000000..a62fa0dc
--- /dev/null
+++ b/crates/vite_task_plan/tests/plan_snapshots/fixtures/pnpm-workspace-packages-optional/pnpm-workspace.yaml
@@ -0,0 +1 @@
+# no `packages` field
diff --git a/crates/vite_task_plan/tests/plan_snapshots/fixtures/pnpm-workspace-packages-optional/snapshots.toml b/crates/vite_task_plan/tests/plan_snapshots/fixtures/pnpm-workspace-packages-optional/snapshots.toml
new file mode 100644
index 00000000..84446107
--- /dev/null
+++ b/crates/vite_task_plan/tests/plan_snapshots/fixtures/pnpm-workspace-packages-optional/snapshots.toml
@@ -0,0 +1,3 @@
+[[plan]]
+name = "allow `packages` in pnpm-workspace.yaml to be optional"
+args = ["run", "hello"]
diff --git a/crates/vite_task_plan/tests/plan_snapshots/fixtures/pnpm-workspace-packages-optional/snapshots/query - allow `packages` in pnpm-workspace.yaml to be optional.snap b/crates/vite_task_plan/tests/plan_snapshots/fixtures/pnpm-workspace-packages-optional/snapshots/query - allow `packages` in pnpm-workspace.yaml to be optional.snap
new file mode 100644
index 00000000..07834655
--- /dev/null
+++ b/crates/vite_task_plan/tests/plan_snapshots/fixtures/pnpm-workspace-packages-optional/snapshots/query - allow `packages` in pnpm-workspace.yaml to be optional.snap	
@@ -0,0 +1,53 @@
+---
+source: crates/vite_task_plan/tests/plan_snapshots/main.rs
+expression: "&plan_json"
+input_file: crates/vite_task_plan/tests/plan_snapshots/fixtures/pnpm-workspace-packages-optional
+---
+{
+  "root_node": {
+    "Expanded": [
+      {
+        "key": [
+          "<workspace>/",
+          "hello"
+        ],
+        "node": {
+          "task_display": {
+            "package_name": "additional-envs",
+            "task_name": "hello",
+            "package_path": "<workspace>/"
+          },
+          "items": [
+            {
+              "execution_item_display": {
+                "task_display": {
+                  "package_name": "additional-envs",
+                  "task_name": "hello",
+                  "package_path": "<workspace>/"
+                },
+                "command": "echo hello",
+                "and_item_index": null,
+                "cwd": "<workspace>/"
+              },
+              "kind": {
+                "Leaf": {
+                  "InProcess": {
+                    "kind": {
+                      "Echo": {
+                        "strings": [
+                          "hello"
+                        ],
+                        "trailing_newline": true
+                      }
+                    }
+                  }
+                }
+              }
+            }
+          ]
+        },
+        "neighbors": []
+      }
+    ]
+  }
+}
diff --git a/crates/vite_task_plan/tests/plan_snapshots/fixtures/pnpm-workspace-packages-optional/snapshots/task graph.snap b/crates/vite_task_plan/tests/plan_snapshots/fixtures/pnpm-workspace-packages-optional/snapshots/task graph.snap
new file mode 100644
index 00000000..2a686412
--- /dev/null
+++ b/crates/vite_task_plan/tests/plan_snapshots/fixtures/pnpm-workspace-packages-optional/snapshots/task graph.snap	
@@ -0,0 +1,35 @@
+---
+source: crates/vite_task_plan/tests/plan_snapshots/main.rs
+expression: task_graph_json
+input_file: crates/vite_task_plan/tests/plan_snapshots/fixtures/pnpm-workspace-packages-optional
+---
+[
+  {
+    "key": [
+      "<workspace>/",
+      "hello"
+    ],
+    "node": {
+      "task_display": {
+        "package_name": "additional-envs",
+        "task_name": "hello",
+        "package_path": "<workspace>/"
+      },
+      "resolved_config": {
+        "command": "echo hello",
+        "resolved_options": {
+          "cwd": "<workspace>/",
+          "cache_config": {
+            "env_config": {
+              "fingerprinted_envs": [],
+              "pass_through_envs": [
+                "<default pass-through envs>"
+              ]
+            }
+          }
+        }
+      }
+    },
+    "neighbors": []
+  }
+]
diff --git a/crates/vite_workspace/src/lib.rs b/crates/vite_workspace/src/lib.rs
index 23c3cb1e..0734b5ac 100644
--- a/crates/vite_workspace/src/lib.rs
+++ b/crates/vite_workspace/src/lib.rs
@@ -25,6 +25,7 @@ struct PnpmWorkspace {
     /// The packages to include in the workspace.
     ///
     /// <https://pnpm.io/pnpm-workspace_yaml>
+    #[serde(default)]
     packages: Vec<Str>,
 }