test(config): add migration tests for litellm provider

* Implement tests for migrating configuration from v1 to v2 for the litellm provider.
* Validate the structure and values of the migrated configuration.
* Ensure migration rejects newer versions of the configuration.
fix(validate): enhance AI provider validation logic
* Consolidate provider validation into a dedicated method.
* Ensure at least one provider is specified and validate its type.
* Check for required fields based on provider type.
fix(mcpserver): update tool set to use new enrichment tool
* Replace RetryMetadataTool with RetryEnrichmentTool in the ToolSet.
fix(tools): refactor tools to use embedding and metadata runners
* Update tools to utilize EmbeddingRunner and MetadataRunner instead of Provider.
* Adjust method calls to align with the new runner interfaces.

internal/config/loader_test.go

@@ -31,9 +31,8 @@ func TestResolvePathIgnoresBareYAMLExtension(t *testing.T) {
 	}
 }
 
-func TestLoadAppliesEnvOverrides(t *testing.T) {
-	configPath := filepath.Join(t.TempDir(), "test.yaml")
-	if err := os.WriteFile(configPath, []byte(`
+const v2ConfigYAML = `
+version: 2
 server:
   port: 8080
 mcp:
@@ -46,18 +45,30 @@ auth:
 database:
   url: "postgres://from-file"
 ai:
-  provider: "litellm"
+  providers:
+    default:
+      type: "litellm"
+      base_url: "http://localhost:4000/v1"
+      api_key: "file-key"
   embeddings:
     dimensions: 1536
-  litellm:
-    base_url: "http://localhost:4000/v1"
-    api_key: "file-key"
+    primary:
+      provider: "default"
+      model: "text-embed"
+  metadata:
+    primary:
+      provider: "default"
+      model: "gpt-4"
 search:
   default_limit: 10
   max_limit: 50
 logging:
   level: "info"
-`), 0o600); err != nil {
+`
+
+func TestLoadAppliesEnvOverrides(t *testing.T) {
+	configPath := filepath.Join(t.TempDir(), "test.yaml")
+	if err := os.WriteFile(configPath, []byte(v2ConfigYAML), 0o600); err != nil {
 		t.Fatalf("write config: %v", err)
 	}
 
@@ -76,8 +87,8 @@ logging:
 	if cfg.Database.URL != "postgres://from-env" {
 		t.Fatalf("database url = %q, want env override", cfg.Database.URL)
 	}
-	if cfg.AI.LiteLLM.APIKey != "env-key" {
-		t.Fatalf("litellm api key = %q, want env override", cfg.AI.LiteLLM.APIKey)
+	if cfg.AI.Providers["default"].APIKey != "env-key" {
+		t.Fatalf("litellm api key = %q, want env override", cfg.AI.Providers["default"].APIKey)
 	}
 	if cfg.Server.Port != 9090 {
 		t.Fatalf("server port = %d, want 9090", cfg.Server.Port)
@@ -90,10 +101,12 @@ logging:
 func TestLoadAppliesOllamaEnvOverrides(t *testing.T) {
 	configPath := filepath.Join(t.TempDir(), "test.yaml")
 	if err := os.WriteFile(configPath, []byte(`
+version: 2
 server:
   port: 8080
 mcp:
   path: "/mcp"
+  session_timeout: "10m"
 auth:
   keys:
     - id: "test"
@@ -101,15 +114,20 @@ auth:
 database:
   url: "postgres://from-file"
 ai:
-  provider: "ollama"
+  providers:
+    local:
+      type: "ollama"
+      base_url: "http://localhost:11434/v1"
+      api_key: "ollama"
   embeddings:
-    model: "nomic-embed-text"
     dimensions: 768
+    primary:
+      provider: "local"
+      model: "nomic-embed-text"
   metadata:
-    model: "llama3.2"
-  ollama:
-    base_url: "http://localhost:11434/v1"
-    api_key: "ollama"
+    primary:
+      provider: "local"
+      model: "llama3.2"
 search:
   default_limit: 10
   max_limit: 50
@@ -127,10 +145,77 @@ logging:
 		t.Fatalf("Load() error = %v", err)
 	}
 
-	if cfg.AI.Ollama.BaseURL != "https://ollama.example.com/v1" {
-		t.Fatalf("ollama base url = %q, want env override", cfg.AI.Ollama.BaseURL)
+	p := cfg.AI.Providers["local"]
+	if p.BaseURL != "https://ollama.example.com/v1" {
+		t.Fatalf("ollama base url = %q, want env override", p.BaseURL)
 	}
-	if cfg.AI.Ollama.APIKey != "remote-key" {
-		t.Fatalf("ollama api key = %q, want env override", cfg.AI.Ollama.APIKey)
+	if p.APIKey != "remote-key" {
+		t.Fatalf("ollama api key = %q, want env override", p.APIKey)
+	}
+}
+
+func TestLoadMigratesV1Config(t *testing.T) {
+	configPath := filepath.Join(t.TempDir(), "v1.yaml")
+	v1 := `
+server:
+  port: 8080
+mcp:
+  path: "/mcp"
+  session_timeout: "10m"
+auth:
+  keys:
+    - id: "test"
+      value: "secret"
+database:
+  url: "postgres://from-file"
+ai:
+  provider: "litellm"
+  embeddings:
+    model: "text-embed"
+    dimensions: 1536
+  metadata:
+    model: "gpt-4"
+    temperature: 0.2
+    fallback_models: ["gpt-3.5"]
+  litellm:
+    base_url: "http://localhost:4000/v1"
+    api_key: "file-key"
+search:
+  default_limit: 10
+  max_limit: 50
+logging:
+  level: "info"
+`
+	if err := os.WriteFile(configPath, []byte(v1), 0o600); err != nil {
+		t.Fatalf("write config: %v", err)
+	}
+
+	cfg, _, err := Load(configPath)
+	if err != nil {
+		t.Fatalf("Load() error = %v", err)
+	}
+
+	if cfg.Version != CurrentConfigVersion {
+		t.Fatalf("version = %d, want %d", cfg.Version, CurrentConfigVersion)
+	}
+	if p, ok := cfg.AI.Providers["default"]; !ok || p.Type != "litellm" || p.APIKey != "file-key" {
+		t.Fatalf("providers[default] = %+v, want litellm/file-key", p)
+	}
+	if cfg.AI.Embeddings.Primary.Model != "text-embed" || cfg.AI.Embeddings.Primary.Provider != "default" {
+		t.Fatalf("embeddings.primary = %+v, want default/text-embed", cfg.AI.Embeddings.Primary)
+	}
+	if cfg.AI.Metadata.Primary.Model != "gpt-4" || cfg.AI.Metadata.Primary.Provider != "default" {
+		t.Fatalf("metadata.primary = %+v, want default/gpt-4", cfg.AI.Metadata.Primary)
+	}
+	if len(cfg.AI.Metadata.Fallbacks) != 1 || cfg.AI.Metadata.Fallbacks[0].Model != "gpt-3.5" {
+		t.Fatalf("metadata.fallbacks = %+v, want [default/gpt-3.5]", cfg.AI.Metadata.Fallbacks)
+	}
+
+	entries, err := filepath.Glob(configPath + ".bak.*")
+	if err != nil {
+		t.Fatalf("glob backups: %v", err)
+	}
+	if len(entries) != 1 {
+		t.Fatalf("backup files = %d, want 1", len(entries))
 	}
 }