fix(captain): default temperature to 0.5 and remove UI control (#14879)

# Pull Request Template

## Description

- Default temperature to 0.5 and remove UI control
- No migrations needed for existing accounts, their current settings are
preserved

## Type of change

- [x] New feature (non-breaking change which adds functionality)

## How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide
instructions so we can reproduce. Please also list any relevant details
for your test configuration.

locally and spec

## Checklist:

- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my code
- [x] I have commented on my code, particularly in hard-to-understand
areas
- [ ] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [x] I have added tests that prove my fix is effective or that my
feature works
- [x] New and existing unit tests pass locally with my changes
- [x] Any dependent changes have been merged and published in downstream
modules

app/javascript/dashboard/components-next/captain/pageComponents/assistant/settings/AssistantSystemSettingsForm.vue

@@ -29,7 +29,6 @@ const initialState = {
   handoffMessage: '',
   resolutionMessage: '',
   instructions: '',
-  temperature: 1,
 };
 
 const state = reactive({ ...initialState });
@@ -57,7 +56,6 @@ const updateStateFromAssistant = assistant => {
   state.handoffMessage = config.handoff_message;
   state.resolutionMessage = config.resolution_message;
   state.instructions = config.instructions;
-  state.temperature = config.temperature || 1;
 };
 
 const handleSystemMessagesUpdate = async () => {
@@ -80,7 +78,6 @@ const handleSystemMessagesUpdate = async () => {
       ...props.assistant.config,
       handoff_message: state.handoffMessage,
       resolution_message: state.resolutionMessage,
-      temperature: state.temperature || 1,
     },
   };
 
@@ -131,26 +128,6 @@ watch(
       class="z-0"
     />
 
-    <div class="flex flex-col gap-2">
-      <label class="text-sm font-medium text-n-slate-12">
-        {{ t('CAPTAIN.ASSISTANTS.FORM.TEMPERATURE.LABEL') }}
-      </label>
-      <div class="flex items-center gap-4">
-        <input
-          v-model="state.temperature"
-          type="range"
-          min="0"
-          max="1"
-          step="0.1"
-          class="w-full"
-        />
-        <span class="text-sm text-n-slate-12">{{ state.temperature }}</span>
-      </div>
-      <p class="text-sm text-n-slate-11 italic">
-        {{ t('CAPTAIN.ASSISTANTS.FORM.TEMPERATURE.DESCRIPTION') }}
-      </p>
-    </div>
-
     <div>
       <Button
         :label="t('CAPTAIN.ASSISTANTS.FORM.UPDATE')"

app/javascript/dashboard/i18n/locale/en/integrations.json

@@ -494,10 +494,6 @@
           "PLACEHOLDER": "Enter assistant name",
           "ERROR": "The name is required"
         },
-        "TEMPERATURE": {
-          "LABEL": "Response Temperature",
-          "DESCRIPTION": "Adjust how creative or restrictive the assistant's responses should be. Lower values produce more focused and deterministic responses, while higher values allow for more creative and varied outputs."
-        },
         "DESCRIPTION": {
           "LABEL": "Description",
           "PLACEHOLDER": "Enter assistant description",

enterprise/app/helpers/captain/chat_helper.rb

@@ -96,7 +96,7 @@ module Captain::ChatHelper
   end
 
   def temperature
-    @assistant&.config&.[]('temperature').to_f || 1
+    @assistant&.config&.[]('temperature').presence&.to_f || 0.5
   end
 
   def resolved_account_id

enterprise/app/models/concerns/agentable.rb

@@ -1,13 +1,15 @@
 module Concerns::Agentable
   extend ActiveSupport::Concern
 
+  DEFAULT_TEMPERATURE = 0.5
+
   def agent
     Agents::Agent.new(
       name: agent_name,
       instructions: ->(context) { agent_instructions(context) },
       tools: agent_tools,
       model: agent_model,
-      temperature: temperature.to_f || 0.7,
+      temperature: temperature.presence&.to_f || DEFAULT_TEMPERATURE,
       response_schema: agent_response_schema
     )
   end

spec/enterprise/models/concerns/agentable_spec.rb

@@ -56,11 +56,11 @@ RSpec.describe Concerns::Agentable do
       dummy_instance.agent
     end
 
-    it 'converts nil temperature to 0.0' do
+    it 'uses default temperature when temperature is nil' do
       dummy_instance.temperature = nil
 
       expect(Agents::Agent).to receive(:new).with(
-        hash_including(temperature: 0.0)
+        hash_including(temperature: 0.5)
       )
 
       dummy_instance.agent

spec/enterprise/services/captain/llm/assistant_chat_service_spec.rb

@@ -39,6 +39,24 @@ RSpec.describe Captain::Llm::AssistantChatService do
       service.generate_response(message_history: [{ role: 'user', content: 'Hello' }])
     end
 
+    it 'uses default temperature when assistant config does not include temperature' do
+      expect(mock_chat).to receive(:with_temperature).with(0.5).and_return(mock_chat)
+      allow(mock_chat).to receive(:ask).and_return(mock_response)
+
+      service = described_class.new(assistant: assistant, conversation: conversation)
+      service.generate_response(message_history: [{ role: 'user', content: 'Hello' }])
+    end
+
+    it 'preserves explicit assistant config temperature' do
+      assistant.update!(config: assistant.config.merge('temperature' => 1.0))
+
+      expect(mock_chat).to receive(:with_temperature).with(1.0).and_return(mock_chat)
+      allow(mock_chat).to receive(:ask).and_return(mock_response)
+
+      service = described_class.new(assistant: assistant, conversation: conversation)
+      service.generate_response(message_history: [{ role: 'user', content: 'Hello' }])
+    end
+
     it 'passes channel_type to the agent session instrumentation' do
       service = described_class.new(assistant: assistant, conversation: conversation)