feat(llm): add Responses API client

config/installation_config.yml

@@ -189,7 +189,7 @@
   type: secret
 - name: CAPTAIN_OPEN_AI_MODEL
   display_title: 'OpenAI Model'
-  description: 'The OpenAI model configured for use in Captain AI. Default: gpt-4.1-mini'
+  description: 'The OpenAI model configured for use in Captain AI. Default: gpt-5.6-luna'
   locked: false
 - name: CAPTAIN_OPEN_AI_ENDPOINT
   display_title: 'OpenAI API Endpoint (optional)'

config/llm.yml

@@ -35,6 +35,18 @@ models:
     provider: openai
     display_name: 'GPT-5.2'
     credit_multiplier: 3
+  gpt-5.6-luna:
+    provider: openai
+    display_name: 'GPT-5.6 Luna'
+    credit_multiplier: 2
+  gpt-5.6-terra:
+    provider: openai
+    display_name: 'GPT-5.6 Terra'
+    credit_multiplier: 3
+  gpt-5.6-sol:
+    provider: openai
+    display_name: 'GPT-5.6 Sol'
+    credit_multiplier: 5
   claude-haiku-4.5:
     provider: anthropic
     display_name: 'Claude Haiku 4.5'
@@ -78,11 +90,14 @@ features:
         gpt-4.1,
         gpt-5.1,
         gpt-5.2,
+        gpt-5.6-luna,
+        gpt-5.6-terra,
         claude-haiku-4.5,
         gemini-3-flash,
         gemini-3-pro,
       ]
-    default: gpt-4.1-mini
+    default: gpt-5.6-luna
+    reasoning_effort: low
   assistant:
     models:
       [
@@ -91,12 +106,16 @@ features:
         gpt-4.1,
         gpt-5.1,
         gpt-5.2,
+        gpt-5.6-luna,
+        gpt-5.6-terra,
+        gpt-5.6-sol,
         claude-haiku-4.5,
         claude-sonnet-4.5,
         gemini-3-flash,
         gemini-3-pro,
       ]
-    default: gpt-4.1
+    default: gpt-5.6-terra
+    reasoning_effort: medium
   copilot:
     models:
       [
@@ -105,16 +124,28 @@ features:
         gpt-4.1,
         gpt-5.1,
         gpt-5.2,
+        gpt-5.6-luna,
+        gpt-5.6-terra,
+        gpt-5.6-sol,
         claude-haiku-4.5,
         claude-sonnet-4.5,
         gemini-3-flash,
         gemini-3-pro,
       ]
-    default: gpt-4.1
+    default: gpt-5.6-terra
+    reasoning_effort: medium
   label_suggestion:
     models:
-      [gpt-4.1-nano, gpt-4.1-mini, gpt-5-mini, gemini-3-flash, claude-haiku-4.5]
-    default: gpt-4.1-mini
+      [
+        gpt-4.1-nano,
+        gpt-4.1-mini,
+        gpt-5-mini,
+        gpt-5.6-luna,
+        gemini-3-flash,
+        claude-haiku-4.5,
+      ]
+    default: gpt-5.6-luna
+    reasoning_effort: low
   document_faq_generation:
     models:
       [
@@ -123,12 +154,16 @@ features:
         gpt-4.1,
         gpt-5.1,
         gpt-5.2,
+        gpt-5.6-luna,
+        gpt-5.6-terra,
+        gpt-5.6-sol,
         claude-haiku-4.5,
         claude-sonnet-4.5,
         gemini-3-flash,
         gemini-3-pro,
       ]
-    default: gpt-4.1-mini
+    default: gpt-5.6-terra
+    reasoning_effort: medium
   conversation_faq_generation:
     models:
       [
@@ -137,15 +172,20 @@ features:
         gpt-4.1,
         gpt-5.1,
         gpt-5.2,
+        gpt-5.6-luna,
+        gpt-5.6-terra,
+        gpt-5.6-sol,
         claude-haiku-4.5,
         claude-sonnet-4.5,
         gemini-3-flash,
         gemini-3-pro,
       ]
-    default: gpt-5.2
+    default: gpt-5.6-terra
+    reasoning_effort: medium
   pdf_faq_generation:
     models: [gpt-4.1-mini, gpt-5-mini, gpt-4.1, gpt-5.1, gpt-5.2]
     default: gpt-4.1-mini
+    reasoning_effort: medium
   help_center_article_generation:
     models:
       [
@@ -154,19 +194,34 @@ features:
         gpt-4.1,
         gpt-5.1,
         gpt-5.2,
+        gpt-5.6-luna,
+        gpt-5.6-terra,
+        gpt-5.6-sol,
         claude-haiku-4.5,
         claude-sonnet-4.5,
         gemini-3-flash,
         gemini-3-pro,
       ]
-    default: gpt-5.2
+    default: gpt-5.6-terra
+    reasoning_effort: medium
   onboarding_content_generation:
     models:
-      [gpt-4.1, gpt-4.1-mini, gpt-5-mini, gpt-5.1, gpt-5.2]
-    default: gpt-4.1
+      [
+        gpt-4.1,
+        gpt-4.1-mini,
+        gpt-5-mini,
+        gpt-5.1,
+        gpt-5.2,
+        gpt-5.6-luna,
+        gpt-5.6-terra,
+        gpt-5.6-sol,
+      ]
+    default: gpt-5.6-terra
+    reasoning_effort: medium
   help_center_query_translation:
-    models: [gpt-4.1-nano, gpt-4.1-mini, gpt-5-mini]
-    default: gpt-4.1-nano
+    models: [gpt-4.1-nano, gpt-4.1-mini, gpt-5-mini, gpt-5.6-luna]
+    default: gpt-5.6-luna
+    reasoning_effort: low
   audio_transcription:
     models: [gpt-4o-mini-transcribe, whisper-1]
     default: gpt-4o-mini-transcribe

config/llm_models.json

@@ -27970,6 +27970,165 @@
       "owned_by": "system"
     }
   },
+  {
+    "id": "gpt-5.6-luna",
+    "name": "GPT-5.6 Luna",
+    "provider": "openai",
+    "family": "gpt",
+    "created_at": null,
+    "context_window": 1050000,
+    "max_output_tokens": 128000,
+    "knowledge_cutoff": "2026-02-16",
+    "modalities": {
+      "input": [
+        "text",
+        "image"
+      ],
+      "output": [
+        "text"
+      ]
+    },
+    "capabilities": [
+      "function_calling",
+      "structured_output",
+      "reasoning",
+      "vision"
+    ],
+    "pricing": {
+      "text_tokens": {
+        "standard": {
+          "input_per_million": 1,
+          "output_per_million": 6
+        }
+      }
+    },
+    "metadata": {
+      "object": "model",
+      "owned_by": "system",
+      "source": "openai_docs",
+      "provider_id": "openai",
+      "open_weights": false,
+      "attachment": true,
+      "temperature": false,
+      "last_updated": "2026-07-10",
+      "cost": {
+        "input": 1,
+        "output": 6
+      },
+      "limit": {
+        "context": 1050000,
+        "input": 922000,
+        "output": 128000
+      },
+      "knowledge": "2026-02-16"
+    }
+  },
+  {
+    "id": "gpt-5.6-terra",
+    "name": "GPT-5.6 Terra",
+    "provider": "openai",
+    "family": "gpt",
+    "created_at": null,
+    "context_window": 1050000,
+    "max_output_tokens": 128000,
+    "knowledge_cutoff": "2026-02-16",
+    "modalities": {
+      "input": [
+        "text",
+        "image"
+      ],
+      "output": [
+        "text"
+      ]
+    },
+    "capabilities": [
+      "function_calling",
+      "structured_output",
+      "reasoning",
+      "vision"
+    ],
+    "pricing": {
+      "text_tokens": {
+        "standard": {
+          "input_per_million": 2.5,
+          "output_per_million": 15
+        }
+      }
+    },
+    "metadata": {
+      "object": "model",
+      "owned_by": "system",
+      "source": "openai_docs",
+      "provider_id": "openai",
+      "open_weights": false,
+      "attachment": true,
+      "temperature": false,
+      "last_updated": "2026-07-10",
+      "cost": {
+        "input": 2.5,
+        "output": 15
+      },
+      "limit": {
+        "context": 1050000,
+        "input": 922000,
+        "output": 128000
+      },
+      "knowledge": "2026-02-16"
+    }
+  },
+  {
+    "id": "gpt-5.6-sol",
+    "name": "GPT-5.6 Sol",
+    "provider": "openai",
+    "family": "gpt",
+    "created_at": null,
+    "context_window": 1050000,
+    "max_output_tokens": 128000,
+    "knowledge_cutoff": "2026-02-16",
+    "modalities": {
+      "input": [
+        "text",
+        "image"
+      ],
+      "output": [
+        "text"
+      ]
+    },
+    "capabilities": [
+      "function_calling",
+      "structured_output",
+      "reasoning",
+      "vision"
+    ],
+    "pricing": {
+      "text_tokens": {
+        "standard": {
+          "input_per_million": 5,
+          "output_per_million": 30
+        }
+      }
+    },
+    "metadata": {
+      "object": "model",
+      "owned_by": "system",
+      "source": "openai_docs",
+      "provider_id": "openai",
+      "open_weights": false,
+      "attachment": true,
+      "temperature": false,
+      "last_updated": "2026-07-10",
+      "cost": {
+        "input": 5,
+        "output": 30
+      },
+      "limit": {
+        "context": 1050000,
+        "input": 922000,
+        "output": 128000
+      },
+      "knowledge": "2026-02-16"
+    }
+  },
   {
     "id": "gpt-audio",
     "name": "gpt-audio",
@@ -61509,4 +61668,4 @@
       "owned_by": "xai"
     }
   }
-]
+]

lib/llm/config.rb

@@ -1,7 +1,7 @@
 require 'ruby_llm'
 
 module Llm::Config
-  DEFAULT_MODEL = 'gpt-4.1-mini'.freeze
+  DEFAULT_MODEL = 'gpt-5.6-luna'.freeze
 
   class << self
     def initialized?

lib/llm/feature_router.rb

@@ -1,7 +1,7 @@
 module Llm::FeatureRouter
   class UnknownFeatureError < StandardError; end
 
-  CAPTAIN_V2_ASSISTANT_MODEL = 'gpt-5.2'.freeze
+  CAPTAIN_V2_ASSISTANT_MODEL = 'gpt-5.6-terra'.freeze
 
   class << self
     def resolve(feature:, account: nil)
@@ -17,6 +17,7 @@ module Llm::FeatureRouter
         feature: feature_key,
         provider: Llm::Models.provider_for(model),
         model: model,
+        reasoning_effort: Llm::Models.reasoning_effort_for(feature_key),
         source: source
       }
     end

lib/llm/models.rb

@@ -15,6 +15,10 @@ module Llm::Models
       features.dig(feature.to_s, 'default')
     end
 
+    def reasoning_effort_for(feature)
+      features.dig(feature.to_s, 'reasoning_effort')
+    end
+
     def models_for(feature)
       features.dig(feature.to_s, 'models') || []
     end
@@ -46,7 +50,8 @@ module Llm::Models
             credit_multiplier: model['credit_multiplier']
           }
         end,
-        default: feature['default']
+        default: feature['default'],
+        reasoning_effort: feature['reasoning_effort']
       }
     end
   end

lib/llm/responses_client.rb

@@ -0,0 +1,209 @@
+require 'openai'
+require 'ruby_llm/tool'
+
+class Llm::ResponsesClient
+  DEFAULT_STORE = false
+  DEFAULT_TEXT_FORMAT = { type: 'text' }.freeze
+  SYSTEM_ROLES = %w[system developer].freeze
+
+  def initialize(api_key:, api_base: nil, client: nil)
+    @client = client || OpenAI::Client.new(access_token: api_key, uri_base: normalized_api_base(api_base))
+  end
+
+  def create(model:, messages:, reasoning_effort: nil, schema: nil, tools: [], metadata: {}, store: DEFAULT_STORE, **options)
+    payload = build_payload(
+      model: model,
+      messages: messages,
+      reasoning_effort: reasoning_effort,
+      schema: schema,
+      tools: tools,
+      metadata: metadata,
+      store: store,
+      options: options
+    )
+    return payload if payload[:error]
+
+    build_response(@client.json_post(path: '/responses', parameters: payload), request_messages: messages)
+  end
+
+  def build_payload(model:, messages:, reasoning_effort: nil, schema: nil, tools: [], metadata: {}, store: DEFAULT_STORE, options: {})
+    input_messages = conversation_messages(messages)
+    return no_conversation_payload(messages) if input_messages.empty?
+
+    payload = {
+      model: model,
+      input: input_messages,
+      store: store,
+      text: { format: text_format(schema) }
+    }
+
+    instructions = instructions_from(messages)
+    payload[:instructions] = instructions if instructions.present?
+    payload[:reasoning] = { effort: reasoning_effort } if reasoning_effort.present?
+    payload[:tools] = normalize_tools(tools) if tools.present?
+    payload[:metadata] = metadata if metadata.present?
+
+    payload.merge!(options.compact)
+    payload
+  end
+
+  def self.extract_output_text(response)
+    Array(response['output']).filter_map do |item|
+      next unless item['type'] == 'message'
+
+      Array(item['content']).filter_map do |content|
+        content['text'] if content['type'] == 'output_text'
+      end.join
+    end.join
+  end
+
+  def self.extract_function_calls(response)
+    Array(response['output']).filter_map do |item|
+      next unless item['type'] == 'function_call'
+
+      {
+        'id' => item['id'],
+        'call_id' => item['call_id'],
+        'name' => item['name'],
+        'arguments' => parse_arguments(item['arguments']),
+        'status' => item['status']
+      }
+    end
+  end
+
+  def self.usage_from(response)
+    usage = response['usage'] || {}
+    {
+      'prompt_tokens' => usage['input_tokens'],
+      'completion_tokens' => usage['output_tokens'],
+      'total_tokens' => usage['total_tokens'],
+      'reasoning_tokens' => usage.dig('output_tokens_details', 'reasoning_tokens')
+    }.compact
+  end
+
+  def self.parse_arguments(arguments)
+    return arguments unless arguments.is_a?(String)
+
+    JSON.parse(arguments)
+  rescue JSON::ParserError
+    arguments
+  end
+
+  private
+
+  def build_response(response, request_messages:)
+    {
+      message: self.class.extract_output_text(response),
+      usage: self.class.usage_from(response),
+      response_id: response['id'],
+      model: response['model'],
+      status: response['status'],
+      function_calls: self.class.extract_function_calls(response),
+      raw_response: response,
+      request_messages: request_messages
+    }
+  end
+
+  def conversation_messages(messages)
+    messages.reject { |message| SYSTEM_ROLES.include?(message[:role].to_s) }.map do |message|
+      {
+        role: message[:role].to_s,
+        content: format_content(message[:content])
+      }
+    end
+  end
+
+  def instructions_from(messages)
+    messages.filter_map do |message|
+      message[:content] if SYSTEM_ROLES.include?(message[:role].to_s)
+    end.join("\n\n")
+  end
+
+  def format_content(content)
+    return content unless content.is_a?(Array)
+
+    content.map do |part|
+      normalized_part = part.deep_symbolize_keys
+      case normalized_part[:type]
+      when 'text'
+        { type: 'input_text', text: normalized_part[:text] }
+      when 'image_url'
+        { type: 'input_image', image_url: normalized_part.dig(:image_url, :url) || normalized_part[:image_url] }
+      else
+        normalized_part
+      end
+    end
+  end
+
+  def text_format(schema)
+    return DEFAULT_TEXT_FORMAT unless schema
+
+    schema_payload = normalize_schema_payload(schema)
+    {
+      type: 'json_schema',
+      name: schema_payload[:name],
+      schema: schema_payload[:schema],
+      strict: schema_payload[:strict]
+    }
+  end
+
+  def normalize_schema_payload(schema)
+    schema_instance = schema.is_a?(Class) ? schema.new : schema
+    raw_schema = schema_instance.respond_to?(:to_json_schema) ? schema_instance.to_json_schema : schema_instance
+    raw_schema = raw_schema.deep_symbolize_keys
+    schema_def = (raw_schema[:schema] || raw_schema).deep_dup
+    strict = raw_schema.key?(:strict) ? raw_schema[:strict] : schema_def.delete(:strict)
+
+    {
+      name: sanitize_schema_name(raw_schema[:name] || 'response'),
+      schema: schema_def,
+      strict: strict.nil? || strict
+    }
+  end
+
+  def normalize_tools(tools)
+    tools.map do |tool|
+      if tool.is_a?(Hash)
+        normalized_tool = tool.deep_symbolize_keys
+        function = normalized_tool[:function]
+        next normalized_tool unless function
+
+        next {
+          type: 'function',
+          name: function[:name],
+          description: function[:description],
+          parameters: function[:parameters],
+          strict: function.fetch(:strict, true)
+        }.compact
+      end
+
+      tool_instance = tool.is_a?(Class) ? tool.new : tool
+      {
+        type: 'function',
+        name: tool_instance.name,
+        description: tool_instance.description,
+        parameters: tool_instance.params_schema || RubyLLM::Tool::SchemaDefinition.from_parameters(tool_instance.parameters)&.json_schema,
+        strict: true
+      }.compact
+    end
+  end
+
+  def no_conversation_payload(messages)
+    {
+      error: 'No conversation messages provided',
+      error_code: 400,
+      request_messages: messages
+    }
+  end
+
+  def sanitize_schema_name(name)
+    sanitized = name.to_s.gsub(/[^a-zA-Z0-9_-]/, '_')
+    sanitized.presence || 'response'
+  end
+
+  def normalized_api_base(api_base)
+    endpoint = api_base.presence || 'https://api.openai.com'
+    endpoint = endpoint.chomp('/')
+    endpoint.delete_suffix('/v1')
+  end
+end

lib/llm_constants.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 module LlmConstants
-  DEFAULT_MODEL = 'gpt-4.1'
+  DEFAULT_MODEL = 'gpt-5.6-luna'
   DEFAULT_EMBEDDING_MODEL = 'text-embedding-3-small'
   PDF_PROCESSING_MODEL = 'gpt-4.1-mini'
 

spec/controllers/api/v1/accounts/captain/preferences_controller_spec.rb

@@ -44,10 +44,12 @@ RSpec.describe 'Api::V1::Accounts::Captain::Preferences', type: :request do
         expect(json_response).to have_key(:providers)
         expect(json_response).to have_key(:models)
         expect(json_response).to have_key(:features)
+        expect(json_response[:models].keys).to include(:'gpt-5.6-luna', :'gpt-5.6-terra', :'gpt-5.6-sol')
+        expect(json_response.dig(:features, :assistant, :models).pluck(:id)).to include('gpt-5.6-luna', 'gpt-5.6-terra', 'gpt-5.6-sol')
       end
 
       it 'returns effective model provider and source for each feature' do
-        account.update!(captain_models: { 'editor' => 'gpt-4.1' })
+        account.update!(captain_models: { 'editor' => 'gpt-5.6-terra' })
 
         get "/api/v1/accounts/#{account.id}/captain/preferences",
             headers: admin.create_new_auth_token,
@@ -55,15 +57,17 @@ RSpec.describe 'Api::V1::Accounts::Captain::Preferences', type: :request do
 
         expect(response).to have_http_status(:success)
         expect(json_response.dig(:features, :editor)).to include(
-          model: 'gpt-4.1',
-          selected: 'gpt-4.1',
+          model: 'gpt-5.6-terra',
+          selected: 'gpt-5.6-terra',
           provider: 'openai',
+          reasoning_effort: 'low',
           source: 'account_override'
         )
         expect(json_response.dig(:features, :label_suggestion)).to include(
           model: Llm::Models.default_model_for('label_suggestion'),
           selected: Llm::Models.default_model_for('label_suggestion'),
           provider: 'openai',
+          reasoning_effort: 'low',
           source: 'default'
         )
       end
@@ -81,7 +85,7 @@ RSpec.describe 'Api::V1::Accounts::Captain::Preferences', type: :request do
         )
       end
 
-      it 'returns GPT-5.2 as the assistant default for V2 accounts' do
+      it 'returns the Captain V2 assistant default for V2 accounts' do
         account.enable_features!('captain_integration_v2')
 
         get "/api/v1/accounts/#{account.id}/captain/preferences",

spec/enterprise/models/account_spec.rb

@@ -258,7 +258,7 @@ RSpec.describe Account, type: :model do
 
       expect(account).to be_feature_enabled('captain_integration')
       expect(account).to be_feature_enabled('captain_integration_v2')
-      expect(account.captain_preferences[:models]['assistant']).to eq('gpt-5.2')
+      expect(account.captain_preferences[:models]['assistant']).to eq(Llm::FeatureRouter::CAPTAIN_V2_ASSISTANT_MODEL)
       expect(account.captain_models).to be_nil
     end
 

spec/enterprise/models/concerns/agentable_spec.rb

@@ -183,7 +183,7 @@ RSpec.describe Concerns::Agentable do
       create(:installation_config, name: 'CAPTAIN_OPEN_AI_MODEL', value: 'gpt-4.1-nano')
       account.enable_features!('captain_integration_v2')
 
-      expect(dummy_instance.send(:agent_model)).to eq('gpt-5.2')
+      expect(dummy_instance.send(:agent_model)).to eq(Llm::FeatureRouter::CAPTAIN_V2_ASSISTANT_MODEL)
       expect(account.reload.captain_models).to be_nil
     end
 

spec/enterprise/services/llm/base_ai_service_spec.rb

@@ -34,7 +34,7 @@ RSpec.describe Llm::BaseAiService do
       create(:installation_config, name: 'CAPTAIN_OPEN_AI_MODEL', value: 'gpt-4.1-nano')
       account.enable_features!('captain_integration_v2')
 
-      expect(described_class.new(feature: 'assistant', account: account).model).to eq('gpt-5.2')
+      expect(described_class.new(feature: 'assistant', account: account).model).to eq(Llm::FeatureRouter::CAPTAIN_V2_ASSISTANT_MODEL)
       expect(account.reload.captain_models).to be_nil
     end
 

spec/lib/llm/feature_router_spec.rb

@@ -12,25 +12,27 @@ RSpec.describe Llm::FeatureRouter do
       expect(resolved).to eq(
         feature: 'editor',
         provider: 'openai',
-        model: 'gpt-4.1-mini',
+        model: 'gpt-5.6-luna',
+        reasoning_effort: 'low',
         source: :default
       )
     end
 
     it 'uses a valid account model override' do
-      account.update!(captain_models: { 'editor' => 'gpt-4.1' })
+      account.update!(captain_models: { 'editor' => 'gpt-5.6-terra' })
 
       resolved = described_class.resolve(feature: 'editor', account: account)
 
       expect(resolved).to include(
         feature: 'editor',
         provider: 'openai',
-        model: 'gpt-4.1',
+        model: 'gpt-5.6-terra',
+        reasoning_effort: 'low',
         source: :account_override
       )
     end
 
-    it 'resolves GPT-5.2 as the assistant default when Captain V2 is enabled without storing an account override' do
+    it 'resolves the Captain V2 assistant default without storing an account override' do
       account.enable_features!('captain_integration_v2')
 
       resolved = described_class.resolve(feature: 'assistant', account: account)
@@ -38,7 +40,8 @@ RSpec.describe Llm::FeatureRouter do
       expect(resolved).to include(
         feature: 'assistant',
         provider: 'openai',
-        model: 'gpt-5.2',
+        model: described_class::CAPTAIN_V2_ASSISTANT_MODEL,
+        reasoning_effort: 'medium',
         source: :default
       )
       expect(account.reload.captain_models).to be_nil
@@ -62,7 +65,8 @@ RSpec.describe Llm::FeatureRouter do
       resolved = described_class.resolve(feature: 'editor', account: account)
 
       expect(resolved).to include(
-        model: 'gpt-4.1-mini',
+        model: 'gpt-5.6-luna',
+        reasoning_effort: 'low',
         source: :default
       )
     end
@@ -73,7 +77,8 @@ RSpec.describe Llm::FeatureRouter do
       resolved = described_class.resolve(feature: 'editor', account: account)
 
       expect(resolved).to include(
-        model: 'gpt-4.1-mini',
+        model: 'gpt-5.6-luna',
+        reasoning_effort: 'low',
         source: :default
       )
     end

spec/lib/llm/models_spec.rb

@@ -27,12 +27,33 @@ RSpec.describe Llm::Models do
     end
 
     it 'routes document and conversation FAQ generation independently' do
-      expect(described_class.default_model_for('document_faq_generation')).to eq('gpt-4.1-mini')
-      expect(described_class.default_model_for('conversation_faq_generation')).to eq('gpt-5.2')
+      expect(described_class.default_model_for('document_faq_generation')).to eq('gpt-5.6-terra')
+      expect(described_class.default_model_for('conversation_faq_generation')).to eq('gpt-5.6-terra')
+    end
+
+    it 'sets reasoning effort for every text generation feature' do
+      features_without_reasoning = %w[audio_transcription help_center_search]
+
+      described_class.features.each_key do |feature_key|
+        if features_without_reasoning.include?(feature_key)
+          expect(described_class.reasoning_effort_for(feature_key)).to be_nil
+        else
+          expect(described_class.reasoning_effort_for(feature_key)).to be_present
+        end
+      end
+    end
+
+    it 'exposes GPT-5.6 models for Captain V2 workflows without changing the legacy PDF path' do
+      expect(described_class.models_for('assistant')).to include('gpt-5.6-luna', 'gpt-5.6-terra', 'gpt-5.6-sol')
+      expect(described_class.models_for('pdf_faq_generation')).not_to include('gpt-5.6-luna', 'gpt-5.6-terra', 'gpt-5.6-sol')
     end
   end
 
   describe '.models' do
+    it 'includes the GPT-5.6 model family' do
+      expect(described_class.models.keys).to include('gpt-5.6-luna', 'gpt-5.6-terra', 'gpt-5.6-sol')
+    end
+
     it 'references existing providers from every model' do
       missing_providers = described_class.models.filter_map do |model_name, config|
         provider = config['provider']
@@ -49,7 +70,9 @@ RSpec.describe Llm::Models do
     it 'returns model metadata for a feature' do
       config = described_class.feature_config('editor')
 
-      expect(config[:default]).to eq('gpt-4.1-mini')
+      expect(config[:default]).to eq('gpt-5.6-luna')
+      expect(config[:reasoning_effort]).to eq('low')
+      expect(config[:models].pluck(:id)).to include('gpt-5.6-luna', 'gpt-5.6-terra')
       expect(config[:models].first).to include(
         id: 'gpt-4.1-mini',
         display_name: 'GPT-4.1 Mini',

spec/lib/llm/responses_client_spec.rb

@@ -0,0 +1,215 @@
+require 'rails_helper'
+
+RSpec.describe Llm::ResponsesClient do
+  let(:openai_client) { instance_double(OpenAI::Client) }
+  let(:client) { described_class.new(api_key: 'test-key', api_base: 'https://api.openai.com/v1', client: openai_client) }
+
+  let(:response_body) do
+    {
+      'id' => 'resp_123',
+      'status' => 'completed',
+      'model' => 'gpt-5.6-terra',
+      'output' => [
+        {
+          'type' => 'message',
+          'content' => [
+            { 'type' => 'output_text', 'text' => 'Hello' }
+          ]
+        },
+        {
+          'type' => 'function_call',
+          'id' => 'fc_123',
+          'call_id' => 'call_123',
+          'name' => 'lookup_faq',
+          'arguments' => '{"query":"billing"}',
+          'status' => 'completed'
+        }
+      ],
+      'usage' => {
+        'input_tokens' => 10,
+        'output_tokens' => 5,
+        'total_tokens' => 15,
+        'output_tokens_details' => { 'reasoning_tokens' => 2 }
+      }
+    }
+  end
+
+  before do
+    allow(openai_client).to receive(:json_post).and_return(response_body)
+  end
+
+  describe '#create' do
+    it 'sends a Responses API payload with reasoning effort and store disabled' do
+      messages = [
+        { role: 'system', content: 'Answer as a support assistant.' },
+        { role: 'user', content: 'Hi' }
+      ]
+
+      result = client.create(
+        model: 'gpt-5.6-terra',
+        messages: messages,
+        reasoning_effort: 'medium',
+        metadata: { feature: 'assistant' }
+      )
+
+      expect(openai_client).to have_received(:json_post).with(
+        path: '/responses',
+        parameters: {
+          model: 'gpt-5.6-terra',
+          input: [{ role: 'user', content: 'Hi' }],
+          store: false,
+          text: { format: { type: 'text' } },
+          instructions: 'Answer as a support assistant.',
+          reasoning: { effort: 'medium' },
+          metadata: { feature: 'assistant' }
+        }
+      )
+      expect(result).to include(
+        message: 'Hello',
+        response_id: 'resp_123',
+        model: 'gpt-5.6-terra',
+        status: 'completed',
+        request_messages: messages
+      )
+      expect(result[:usage]).to eq(
+        'prompt_tokens' => 10,
+        'completion_tokens' => 5,
+        'total_tokens' => 15,
+        'reasoning_tokens' => 2
+      )
+      expect(result[:function_calls]).to contain_exactly(
+        'id' => 'fc_123',
+        'call_id' => 'call_123',
+        'name' => 'lookup_faq',
+        'arguments' => { 'query' => 'billing' },
+        'status' => 'completed'
+      )
+    end
+
+    it 'returns a local error when no conversation messages are present' do
+      result = client.create(
+        model: 'gpt-5.6-terra',
+        messages: [{ role: 'system', content: 'Only instructions' }],
+        reasoning_effort: 'low'
+      )
+
+      expect(openai_client).not_to have_received(:json_post)
+      expect(result).to eq(
+        error: 'No conversation messages provided',
+        error_code: 400,
+        request_messages: [{ role: 'system', content: 'Only instructions' }]
+      )
+    end
+  end
+
+  describe '#build_payload' do
+    class TestResponsesSchema
+      def to_json_schema
+        {
+          name: 'captain.response',
+          schema: {
+            type: 'object',
+            properties: {
+              response: { type: 'string' }
+            },
+            required: ['response'],
+            additionalProperties: false
+          },
+          strict: true
+        }
+      end
+    end
+
+    it 'uses Responses text.format for structured outputs' do
+      payload = client.build_payload(
+        model: 'gpt-5.6-terra',
+        messages: [{ role: 'user', content: 'Summarize' }],
+        schema: TestResponsesSchema
+      )
+
+      expect(payload[:text]).to eq(
+        format: {
+          type: 'json_schema',
+          name: 'captain_response',
+          schema: {
+            type: 'object',
+            properties: {
+              response: { type: 'string' }
+            },
+            required: ['response'],
+            additionalProperties: false
+          },
+          strict: true
+        }
+      )
+    end
+
+    it 'normalizes chat-style function tools to Responses function tools' do
+      payload = client.build_payload(
+        model: 'gpt-5.6-terra',
+        messages: [{ role: 'user', content: 'Find docs' }],
+        tools: [
+          {
+            type: 'function',
+            function: {
+              name: 'lookup_faq',
+              description: 'Search FAQs',
+              parameters: {
+                type: 'object',
+                properties: {
+                  query: { type: 'string' }
+                },
+                required: ['query']
+              }
+            }
+          }
+        ]
+      )
+
+      expect(payload[:tools]).to eq(
+        [
+          {
+            type: 'function',
+            name: 'lookup_faq',
+            description: 'Search FAQs',
+            parameters: {
+              type: 'object',
+              properties: {
+                query: { type: 'string' }
+              },
+              required: ['query']
+            },
+            strict: true
+          }
+        ]
+      )
+    end
+
+    it 'normalizes multimodal chat content to Responses input blocks' do
+      payload = client.build_payload(
+        model: 'gpt-5.6-terra',
+        messages: [
+          {
+            role: 'user',
+            content: [
+              { type: 'text', text: 'What is in this image?' },
+              { type: 'image_url', image_url: { url: 'https://example.com/image.png' } }
+            ]
+          }
+        ]
+      )
+
+      expect(payload[:input]).to eq(
+        [
+          {
+            role: 'user',
+            content: [
+              { type: 'input_text', text: 'What is in this image?' },
+              { type: 'input_image', image_url: 'https://example.com/image.png' }
+            ]
+          }
+        ]
+      )
+    end
+  end
+end

spec/models/account_spec.rb

@@ -393,10 +393,10 @@ RSpec.describe Account do
         end
       end
 
-      it 'returns GPT-5.2 for assistant when Captain V2 is enabled' do
+      it 'returns the Captain V2 default for assistant when Captain V2 is enabled' do
         account.enable_features!('captain_integration_v2')
 
-        expect(account.captain_preferences[:models]['assistant']).to eq('gpt-5.2')
+        expect(account.captain_preferences[:models]['assistant']).to eq(Llm::FeatureRouter::CAPTAIN_V2_ASSISTANT_MODEL)
         expect(account.reload.captain_models).to be_nil
       end
     end