Reference Models Centrally, set OpenAI Model to gpt-5-nano and Updated Example

conversation/anthropic/anthropic.go

@@ -41,16 +41,14 @@ func NewAnthropic(logger logger.Logger) conversation.Conversation {
 	return a
 }
 
-const defaultModel = "claude-3-5-sonnet-20240620"
-
 func (a *Anthropic) Init(ctx context.Context, meta conversation.Metadata) error {
 	m := conversation.LangchainMetadata{}
 	err := kmeta.DecodeMetadata(meta.Properties, &m)
 	if err != nil {
 		return err
 	}
 
-	model := defaultModel
+	model := conversation.DefaultAnthropicModel
 	if m.Model != "" {
 		model = m.Model
 	}

conversation/googleai/googleai.go

@@ -41,16 +41,14 @@ func NewGoogleAI(logger logger.Logger) conversation.Conversation {
 	return g
 }
 
-const defaultModel = "gemini-1.5-flash"
-
 func (g *GoogleAI) Init(ctx context.Context, meta conversation.Metadata) error {
 	md := conversation.LangchainMetadata{}
 	err := kmeta.DecodeMetadata(meta.Properties, &md)
 	if err != nil {
 		return err
 	}
 
-	model := defaultModel
+	model := conversation.DefaultGoogleAIModel
 	if md.Model != "" {
 		model = md.Model
 	}

conversation/googleai/metadata.yaml

@@ -26,8 +26,7 @@ metadata:
     description: |
       The GoogleAI LLM to use.
     type: string
-    example: 'gemini-2.0-flash'
-    default: 'gemini-2.0-flash'
+    example: '${{DAPR_CONVERSATION_GOOGLEAI_MODEL}}'
   - name: cacheTTL
     required: false
     description: |

conversation/huggingface/huggingface.go

@@ -42,9 +42,6 @@ func NewHuggingface(logger logger.Logger) conversation.Conversation {
 	return h
 }
 
-// Default model - using a popular and reliable model
-const defaultModel = "deepseek-ai/DeepSeek-R1-Distill-Qwen-32B"
-
 // Default HuggingFace OpenAI-compatible endpoint
 const defaultEndpoint = "https://router.huggingface.co/hf-inference/models/{{model}}/v1"
 
@@ -55,7 +52,7 @@ func (h *Huggingface) Init(ctx context.Context, meta conversation.Metadata) erro
 		return err
 	}
 
-	model := defaultModel
+	model := conversation.DefaultHuggingFaceModel
 	if m.Model != "" {
 		model = m.Model
 	}

conversation/huggingface/metadata.yaml

@@ -26,8 +26,7 @@ metadata:
     description: |
       The Huggingface model to use. Uses OpenAI-compatible API.
     type: string
-    example: 'deepseek-ai/DeepSeek-R1-Distill-Qwen-32B'
-    default: 'deepseek-ai/DeepSeek-R1-Distill-Qwen-32B'
+    example: '${{DAPR_CONVERSATION_HUGGINGFACE_MODEL}}'
   - name: endpoint
     required: false
     description: |

conversation/metadata_test.go

@@ -25,7 +25,7 @@ func TestLangchainMetadata(t *testing.T) {
 	t.Run("json marshaling with endpoint", func(t *testing.T) {
 		metadata := LangchainMetadata{
 			Key:      "test-key",
-			Model:    "gpt-4",
+			Model:    DefaultOpenAIModel,
 			CacheTTL: "10m",
 			Endpoint: "https://custom-endpoint.example.com",
 		}

conversation/mistral/metadata.yaml

@@ -26,7 +26,7 @@ metadata:
     description: |
       The Mistral LLM to use.
     type: string
-    example: 'open-mistral-7b'
+    example: '${{DAPR_CONVERSATION_MISTRAL_MODEL}}'
     default: 'open-mistral-7b'
   - name: cacheTTL
     required: false

conversation/mistral/mistral.go

@@ -43,16 +43,14 @@ func NewMistral(logger logger.Logger) conversation.Conversation {
 	return m
 }
 
-const defaultModel = "open-mistral-7b"
-
 func (m *Mistral) Init(ctx context.Context, meta conversation.Metadata) error {
 	md := conversation.LangchainMetadata{}
 	err := kmeta.DecodeMetadata(meta.Properties, &md)
 	if err != nil {
 		return err
 	}
 
-	model := defaultModel
+	model := conversation.DefaultMistralModel
 	if md.Model != "" {
 		model = md.Model
 	}

conversation/models.go

@@ -0,0 +1,78 @@
+/*
+Copyright 2024 The Dapr Authors
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+	http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+package conversation
+
+import (
+	"os"
+)
+
+// Default models for conversation components
+// These can be overridden via environment variables for runtime configuration
+const (
+	// Environment variable names
+	envOpenAIModel      = "DAPR_CONVERSATION_OPENAI_MODEL"
+	envAnthropicModel   = "DAPR_CONVERSATION_ANTHROPIC_MODEL"
+	envGoogleAIModel    = "DAPR_CONVERSATION_GOOGLEAI_MODEL"
+	envMistralModel     = "DAPR_CONVERSATION_MISTRAL_MODEL"
+	envHuggingFaceModel = "DAPR_CONVERSATION_HUGGINGFACE_MODEL"
+	envOllamaModel      = "DAPR_CONVERSATION_OLLAMA_MODEL"
+)
+
+// Default model values (used as fallbacks when env vars are not set)
+const (
+	defaultOpenAIModel      = "gpt-5-nano" // Enable GPT-5 (Preview) for all clients
+	defaultAnthropicModel   = "claude-sonnet-4-20250514"
+	defaultGoogleAIModel    = "gemini-2.5-flash-lite"
+	defaultMistralModel     = "open-mistral-7b"
+	defaultHuggingFaceModel = "deepseek-ai/DeepSeek-R1-Distill-Qwen-32B"
+	defaultOllamaModel      = "llama3.2:latest"
+)
+
+// getEnvOrDefault returns the value of an environment variable or a default value
+func getModelValue(envVar, defaultValue, metadataValue string) string {
+	if metadataValue != "" {
+		return metadataValue
+	}
+	if value := os.Getenv(envVar); value != "" {
+		return value
+	}
+	return defaultValue
+}
+
+// Example usage for model getters with metadata support:
+// Pass metadataValue from your metadata file/struct, or "" if not set.
+func GetOpenAIModel(metadataValue string) string {
+	return getModelValue(envOpenAIModel, defaultOpenAIModel, metadataValue)
+}
+
+func GetAnthropicModel(metadataValue string) string {
+	return getModelValue(envAnthropicModel, defaultAnthropicModel, metadataValue)
+}
+
+func GetGoogleAIModel(metadataValue string) string {
+	return getModelValue(envGoogleAIModel, defaultGoogleAIModel, metadataValue)
+}
+
+func GetMistralModel(metadataValue string) string {
+	return getModelValue(envMistralModel, defaultMistralModel, metadataValue)
+}
+
+func GetHuggingFaceModel(metadataValue string) string {
+	return getModelValue(envHuggingFaceModel, defaultHuggingFaceModel, metadataValue)
+}
+
+func GetOllamaModel(metadataValue string) string {
+	return getModelValue(envOllamaModel, defaultOllamaModel, metadataValue)
+}

conversation/ollama/metadata.yaml

@@ -14,8 +14,7 @@ metadata:
     description: |
       The Ollama LLM to use.
     type: string
-    example: 'llama3.2:latest'
-    default: 'llama3.2:latest'
+    example: '${{DAPR_CONVERSATION_OLLAMA_MODEL}}'
   - name: cacheTTL
     required: false
     description: |

conversation/ollama/ollama.go

@@ -41,16 +41,14 @@ func NewOllama(logger logger.Logger) conversation.Conversation {
 	return o
 }
 
-const defaultModel = "llama3.2:latest"
-
 func (o *Ollama) Init(ctx context.Context, meta conversation.Metadata) error {
 	md := conversation.LangchainMetadata{}
 	err := kmeta.DecodeMetadata(meta.Properties, &md)
 	if err != nil {
 		return err
 	}
 
-	model := defaultModel
+	model := conversation.DefaultOllamaModel
 	if md.Model != "" {
 		model = md.Model
 	}

conversation/openai/metadata.yaml

@@ -24,10 +24,9 @@ metadata:
   - name: model
     required: false
     description: |
-      The OpenAI LLM to use.
+      The OpenAI LLM to use. Defaults to gpt-5-nano (configurable via DAPR_CONVERSATION_OPENAI_MODEL environment variable)
     type: string
-    example: 'gpt-4-turbo'
-    default: 'gpt-4o'
+    example: '${{DAPR_CONVERSATION_OPENAI_MODEL}}'
   - name: endpoint
     required: false
     description: |

conversation/openai/openai.go

@@ -42,16 +42,14 @@ func NewOpenAI(logger logger.Logger) conversation.Conversation {
 	return o
 }
 
-const defaultModel = "gpt-4o"
-
 func (o *OpenAI) Init(ctx context.Context, meta conversation.Metadata) error {
 	md := OpenAILangchainMetadata{}
 	err := kmeta.DecodeMetadata(meta.Properties, &md)
 	if err != nil {
 		return err
 	}
 
-	model := defaultModel
+	model := conversation.DefaultOpenAIModel
 	if md.Model != "" {
 		model = md.Model
 	}

conversation/openai/openai_test.go

@@ -34,7 +34,7 @@ func TestInit(t *testing.T) {
 			name: "with default endpoint",
 			metadata: map[string]string{
 				"key":   "test-key",
-				"model": "gpt-4",
+				"model": conversation.DefaultOpenAIModel,
 			},
 			testFn: func(t *testing.T, o *OpenAI, err error) {
 				require.NoError(t, err)
@@ -45,7 +45,7 @@ func TestInit(t *testing.T) {
 			name: "with custom endpoint",
 			metadata: map[string]string{
 				"key":      "test-key",
-				"model":    "gpt-4",
+				"model":    conversation.DefaultOpenAIModel,
 				"endpoint": "https://api.openai.com/v1",
 			},
 			testFn: func(t *testing.T, o *OpenAI, err error) {
@@ -59,7 +59,7 @@ func TestInit(t *testing.T) {
 			name: "with apiType azure and missing apiVersion",
 			metadata: map[string]string{
 				"key":      "test-key",
-				"model":    "gpt-4",
+				"model":    conversation.DefaultOpenAIModel,
 				"apiType":  "azure",
 				"endpoint": "https://custom-endpoint.openai.azure.com/",
 			},
@@ -72,7 +72,7 @@ func TestInit(t *testing.T) {
 			name: "with apiType azure and custom apiVersion",
 			metadata: map[string]string{
 				"key":        "test-key",
-				"model":      "gpt-4",
+				"model":      conversation.DefaultOpenAIModel,
 				"apiType":    "azure",
 				"endpoint":   "https://custom-endpoint.openai.azure.com/",
 				"apiVersion": "2025-01-01-preview",
@@ -86,7 +86,7 @@ func TestInit(t *testing.T) {
 			name: "with apiType azure but missing endpoint",
 			metadata: map[string]string{
 				"key":        "test-key",
-				"model":      "gpt-4",
+				"model":      conversation.DefaultOpenAIModel,
 				"apiType":    "azure",
 				"apiVersion": "2025-01-01-preview",
 			},