DEV: gracefully handle missing parameters (#37705)

Avoid a 500 error when params are missing

plugins/discourse-ai/app/controllers/discourse_ai/admin/ai_tools_controller.rb

@@ -101,7 +101,7 @@ module DiscourseAi
 
       def test
         @ai_tool.assign_attributes(ai_tool_params) if params[:ai_tool]
-        parameters = params[:parameters].to_unsafe_h
+        parameters = params[:parameters]&.to_unsafe_h || {}
 
         # we need an llm so we have a tokenizer
         # but will do without if none is available

plugins/discourse-ai/spec/requests/admin/ai_tools_controller_spec.rb

@@ -385,6 +385,13 @@ RSpec.describe DiscourseAi::Admin::AiToolsController do
       expect(response.status).to eq(404)
     end
 
+    it "handles missing parameters gracefully" do
+      post "/admin/plugins/discourse-ai/ai-tools/#{ai_tool.id}/test.json", params: {}
+
+      expect(response.status).to eq(200)
+      expect(response.parsed_body["output"]).to eq({})
+    end
+
     it "handles exceptions during tool execution" do
       ai_tool.update!(script: "function invoke(params) { throw new Error('Test error'); }")