Add environment variable resolution for agent settings

- Introduce `resolveEnvStrings` function to handle `$ENV.XXX` references in the agent's DSL settings, ensuring that environment variables are correctly substituted in system and uses fields.
- Enhance `Load` function to call `resolveEnvStrings` during the loading process, improving the configuration handling for agents.
- Add comprehensive unit tests for `resolveEnvStrings` to validate the correct resolution of environment variables across various fields and scenarios, including handling of undefined variables and plain strings.
- Ensure that the implementation maintains existing functionality while enhancing flexibility for environment-based configurations.

agent/load.go

@@ -6,6 +6,7 @@ import (
 
 	"github.com/yaoapp/gou/application"
 	"github.com/yaoapp/gou/connector"
+	"github.com/yaoapp/gou/helper"
 	"github.com/yaoapp/yao/agent/assistant"
 	"github.com/yaoapp/yao/agent/context"
 	"github.com/yaoapp/yao/agent/i18n"
@@ -46,6 +47,9 @@ func Load(cfg config.Config) error {
 		setting.StoreSetting.MaxSize = 20 // default is 20
 	}
 
+	// Resolve $ENV.XXX references in system and uses fields
+	resolveEnvStrings(&setting)
+
 	// Default Assistant, Agent is the developer name, Mohe is the brand name of the assistant
 	if setting.Uses == nil {
 		setting.Uses = &types.Uses{Default: "mohe"} // Agent is the developer name, Mohe is the brand name of the assistant
@@ -444,3 +448,36 @@ func defaultAssistant() (*assistant.Assistant, error) {
 	}
 	return assistant.Get(agentDSL.Uses.Default)
 }
+
+// resolveEnvStrings resolves $ENV.XXX references in agent.yml string fields.
+// agent.yml is parsed via yaml.Unmarshal which does not handle $ENV substitution,
+// unlike connector files which call helper.EnvString explicitly during Register.
+func resolveEnvStrings(setting *types.DSL) {
+	if setting.System != nil {
+		setting.System.Default = helper.EnvString(setting.System.Default)
+		setting.System.Keyword = helper.EnvString(setting.System.Keyword)
+		setting.System.QueryDSL = helper.EnvString(setting.System.QueryDSL)
+		setting.System.Title = helper.EnvString(setting.System.Title)
+		setting.System.Prompt = helper.EnvString(setting.System.Prompt)
+		setting.System.RobotPrompt = helper.EnvString(setting.System.RobotPrompt)
+		setting.System.NeedSearch = helper.EnvString(setting.System.NeedSearch)
+		setting.System.Entity = helper.EnvString(setting.System.Entity)
+	}
+
+	if setting.Uses != nil {
+		setting.Uses.Default = helper.EnvString(setting.Uses.Default)
+		setting.Uses.Title = helper.EnvString(setting.Uses.Title)
+		setting.Uses.Prompt = helper.EnvString(setting.Uses.Prompt)
+		setting.Uses.RobotPrompt = helper.EnvString(setting.Uses.RobotPrompt)
+		setting.Uses.Vision = helper.EnvString(setting.Uses.Vision)
+		setting.Uses.Audio = helper.EnvString(setting.Uses.Audio)
+		setting.Uses.Search = helper.EnvString(setting.Uses.Search)
+		setting.Uses.Fetch = helper.EnvString(setting.Uses.Fetch)
+		setting.Uses.Web = helper.EnvString(setting.Uses.Web)
+		setting.Uses.Keyword = helper.EnvString(setting.Uses.Keyword)
+		setting.Uses.QueryDSL = helper.EnvString(setting.Uses.QueryDSL)
+		setting.Uses.Rerank = helper.EnvString(setting.Uses.Rerank)
+	}
+
+	setting.Cache = helper.EnvString(setting.Cache)
+}

agent/load_test.go

@@ -8,6 +8,7 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"github.com/yaoapp/yao/agent/assistant"
+	"github.com/yaoapp/yao/agent/types"
 	"github.com/yaoapp/yao/config"
 	"github.com/yaoapp/yao/test"
 )
@@ -211,6 +212,112 @@ func TestGetGlobalPromptsWithDisableFlag(t *testing.T) {
 	})
 }
 
+func TestResolveEnvStrings(t *testing.T) {
+	t.Setenv("TEST_CONNECTOR", "openai.gpt-5")
+	t.Setenv("TEST_ASSISTANT", "my-assistant")
+	t.Setenv("TEST_CACHE", "my-cache")
+
+	t.Run("SystemFields", func(t *testing.T) {
+		setting := &types.DSL{
+			System: &types.System{
+				Default:     "$ENV.TEST_CONNECTOR",
+				Keyword:     "$ENV.TEST_CONNECTOR",
+				QueryDSL:    "$ENV.TEST_CONNECTOR",
+				Title:       "$ENV.TEST_CONNECTOR",
+				Prompt:      "$ENV.TEST_CONNECTOR",
+				RobotPrompt: "$ENV.TEST_CONNECTOR",
+				NeedSearch:  "$ENV.TEST_CONNECTOR",
+				Entity:      "$ENV.TEST_CONNECTOR",
+			},
+		}
+		resolveEnvStrings(setting)
+
+		assert.Equal(t, "openai.gpt-5", setting.System.Default)
+		assert.Equal(t, "openai.gpt-5", setting.System.Keyword)
+		assert.Equal(t, "openai.gpt-5", setting.System.QueryDSL)
+		assert.Equal(t, "openai.gpt-5", setting.System.Title)
+		assert.Equal(t, "openai.gpt-5", setting.System.Prompt)
+		assert.Equal(t, "openai.gpt-5", setting.System.RobotPrompt)
+		assert.Equal(t, "openai.gpt-5", setting.System.NeedSearch)
+		assert.Equal(t, "openai.gpt-5", setting.System.Entity)
+	})
+
+	t.Run("UsesFields", func(t *testing.T) {
+		setting := &types.DSL{
+			Uses: &types.Uses{
+				Default:     "$ENV.TEST_ASSISTANT",
+				Title:       "$ENV.TEST_ASSISTANT",
+				Prompt:      "$ENV.TEST_ASSISTANT",
+				RobotPrompt: "$ENV.TEST_ASSISTANT",
+				Vision:      "$ENV.TEST_ASSISTANT",
+				Audio:       "$ENV.TEST_ASSISTANT",
+				Search:      "$ENV.TEST_ASSISTANT",
+				Fetch:       "$ENV.TEST_ASSISTANT",
+				Web:         "$ENV.TEST_ASSISTANT",
+				Keyword:     "$ENV.TEST_ASSISTANT",
+				QueryDSL:    "$ENV.TEST_ASSISTANT",
+				Rerank:      "$ENV.TEST_ASSISTANT",
+			},
+		}
+		resolveEnvStrings(setting)
+
+		assert.Equal(t, "my-assistant", setting.Uses.Default)
+		assert.Equal(t, "my-assistant", setting.Uses.Title)
+		assert.Equal(t, "my-assistant", setting.Uses.Prompt)
+		assert.Equal(t, "my-assistant", setting.Uses.RobotPrompt)
+		assert.Equal(t, "my-assistant", setting.Uses.Vision)
+		assert.Equal(t, "my-assistant", setting.Uses.Audio)
+		assert.Equal(t, "my-assistant", setting.Uses.Search)
+		assert.Equal(t, "my-assistant", setting.Uses.Fetch)
+		assert.Equal(t, "my-assistant", setting.Uses.Web)
+		assert.Equal(t, "my-assistant", setting.Uses.Keyword)
+		assert.Equal(t, "my-assistant", setting.Uses.QueryDSL)
+		assert.Equal(t, "my-assistant", setting.Uses.Rerank)
+	})
+
+	t.Run("CacheField", func(t *testing.T) {
+		setting := &types.DSL{Cache: "$ENV.TEST_CACHE"}
+		resolveEnvStrings(setting)
+		assert.Equal(t, "my-cache", setting.Cache)
+	})
+
+	t.Run("PlainStringsUnchanged", func(t *testing.T) {
+		setting := &types.DSL{
+			Cache: "plain-cache",
+			System: &types.System{
+				Default: "openai.gpt-5",
+			},
+			Uses: &types.Uses{
+				Default: "mohe",
+				Title:   "__yao.title",
+			},
+		}
+		resolveEnvStrings(setting)
+
+		assert.Equal(t, "plain-cache", setting.Cache)
+		assert.Equal(t, "openai.gpt-5", setting.System.Default)
+		assert.Equal(t, "mohe", setting.Uses.Default)
+		assert.Equal(t, "__yao.title", setting.Uses.Title)
+	})
+
+	t.Run("NilSystemAndUses", func(t *testing.T) {
+		setting := &types.DSL{Cache: "test"}
+		assert.NotPanics(t, func() {
+			resolveEnvStrings(setting)
+		})
+	})
+
+	t.Run("UndefinedEnvReturnsEmpty", func(t *testing.T) {
+		setting := &types.DSL{
+			System: &types.System{
+				Default: "$ENV.UNDEFINED_VAR_12345",
+			},
+		}
+		resolveEnvStrings(setting)
+		assert.Equal(t, "", setting.System.Default)
+	})
+}
+
 func TestGlobalPromptsContent(t *testing.T) {
 	prepare(t)
 	defer test.Clean()