diff --git a/lib/completions/dialects/dialect.rb b/lib/completions/dialects/dialect.rb
index 9361d8ba..465884e2 100644
--- a/lib/completions/dialects/dialect.rb
+++ b/lib/completions/dialects/dialect.rb
@@ -158,7 +158,7 @@ module DiscourseAi
           return "" if prompt.tools.blank?
 
           has_arrays =
-            prompt.tools.any? { |tool| tool[:parameters].any? { |p| p[:type] == "array" } }
+            prompt.tools.any? { |tool| tool[:parameters]&.any? { |p| p[:type] == "array" } }
 
           (<<~TEXT).strip
             #{self.class.tool_preamble(include_array_tip: has_arrays)}
diff --git a/spec/lib/completions/dialects/dialect_spec.rb b/spec/lib/completions/dialects/dialect_spec.rb
index db481e94..2410f415 100644
--- a/spec/lib/completions/dialects/dialect_spec.rb
+++ b/spec/lib/completions/dialects/dialect_spec.rb
@@ -47,6 +47,15 @@ RSpec.describe DiscourseAi::Completions::Dialects::Dialect do
 
       expect(dialect.build_tools_prompt).to include("array")
     end
+
+    it "does not break if there are no params" do
+      prompt = DiscourseAi::Completions::Prompt.new("12345")
+      prompt.tools = [{ name: "categories", description: "lookup all categories" }]
+
+      dialect = TestDialect.new(prompt, "test")
+
+      expect(dialect.build_tools_prompt).not_to include("array")
+    end
   end
 
   describe "#trim_messages" do