diff --git a/crates/agent/src/tests/mod.rs b/crates/agent/src/tests/mod.rs
index ddddbfc5279ca23fb95527892e929b23b8cefbf6..20fc40f242831552630f1e15f59917fd80b1ecdb 100644
--- a/crates/agent/src/tests/mod.rs
+++ b/crates/agent/src/tests/mod.rs
@@ -160,6 +160,42 @@ async fn test_system_prompt(cx: &mut TestAppContext) {
     );
 }
 
+#[gpui::test]
+async fn test_system_prompt_without_tools(cx: &mut TestAppContext) {
+    let ThreadTest { model, thread, .. } = setup(cx, TestModel::Fake).await;
+    let fake_model = model.as_fake();
+
+    thread
+        .update(cx, |thread, cx| {
+            thread.send(UserMessageId::new(), ["abc"], cx)
+        })
+        .unwrap();
+    cx.run_until_parked();
+    let mut pending_completions = fake_model.pending_completions();
+    assert_eq!(
+        pending_completions.len(),
+        1,
+        "unexpected pending completions: {:?}",
+        pending_completions
+    );
+
+    let pending_completion = pending_completions.pop().unwrap();
+    assert_eq!(pending_completion.messages[0].role, Role::System);
+
+    let system_message = &pending_completion.messages[0];
+    let system_prompt = system_message.content[0].to_str().unwrap();
+    assert!(
+        !system_prompt.contains("## Tool Use"),
+        "unexpected system message: {:?}",
+        system_message
+    );
+    assert!(
+        !system_prompt.contains("## Fixing Diagnostics"),
+        "unexpected system message: {:?}",
+        system_message
+    );
+}
+
 #[gpui::test]
 async fn test_prompt_caching(cx: &mut TestAppContext) {
     let ThreadTest { model, thread, .. } = setup(cx, TestModel::Fake).await;
diff --git a/crates/agent/src/thread.rs b/crates/agent/src/thread.rs
index 4016f3a5f53da95c0adca80ebfc5808addd55e09..64e512690beeaebd4a343bc5f2df473c795aed3f 100644
--- a/crates/agent/src/thread.rs
+++ b/crates/agent/src/thread.rs
@@ -1816,9 +1816,15 @@ impl Thread {
         log::debug!("Completion intent: {:?}", completion_intent);
         log::debug!("Completion mode: {:?}", self.completion_mode);
 
-        let messages = self.build_request_messages(cx);
+        let available_tools: Vec<_> = self
+            .running_turn
+            .as_ref()
+            .map(|turn| turn.tools.keys().cloned().collect())
+            .unwrap_or_default();
+
+        log::debug!("Request includes {} tools", available_tools.len());
+        let messages = self.build_request_messages(available_tools, cx);
         log::debug!("Request will include {} messages", messages.len());
-        log::debug!("Request includes {} tools", tools.len());
 
         let request = LanguageModelRequest {
             thread_id: Some(self.id.to_string()),
@@ -1909,7 +1915,11 @@ impl Thread {
         self.running_turn.as_ref()?.tools.get(name).cloned()
     }
 
-    fn build_request_messages(&self, cx: &App) -> Vec<LanguageModelRequestMessage> {
+    fn build_request_messages(
+        &self,
+        available_tools: Vec<SharedString>,
+        cx: &App,
+    ) -> Vec<LanguageModelRequestMessage> {
         log::trace!(
             "Building request messages from {} thread messages",
             self.messages.len()
@@ -1917,7 +1927,7 @@ impl Thread {
 
         let system_prompt = SystemPromptTemplate {
             project: self.project_context.read(cx),
-            available_tools: self.tools.keys().cloned().collect(),
+            available_tools,
         }
         .render(&self.templates)
         .context("failed to build system prompt")