diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 9ca4762..b3cdf0e 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -50,6 +50,8 @@ jobs:
         with:
           command: test
           args: --all-features --all
+      - name: studies command
+        run: cargo run -- studies --solvers $(cargo run -- solver random) --problems $(cargo run -- problem sigopt --dim 5 ackley) --repeats 10 --budget 100
 
   lints:
     name: Lints
diff --git a/kurobako_problems/src/sigopt.rs b/kurobako_problems/src/sigopt.rs
index 07fc883..f84ccb4 100644
--- a/kurobako_problems/src/sigopt.rs
+++ b/kurobako_problems/src/sigopt.rs
@@ -31,16 +31,19 @@ pub struct SigoptProblemRecipe {
 
     /// Dimension of the test function.
     #[serde(skip_serializing_if = "Option::is_none")]
+    #[serde(default)]
     #[structopt(long)]
     pub dim: Option<usize>,
 
     /// Input resolution of the test function.
     #[serde(skip_serializing_if = "Option::is_none")]
+    #[serde(default)]
     #[structopt(long)]
     pub res: Option<f64>,
 
     /// List of the dimensions which should only accept integer values.
     #[serde(skip_serializing_if = "Vec::is_empty")]
+    #[serde(default)]
     #[structopt(long)]
     pub int: Vec<usize>,
 }