feat: support API key resolution from env var

Author: voocel

internal/agent/session.go

@@ -289,13 +289,15 @@ func (s *Session) BaseURL() string {
 }
 
 // resolveCredentials returns the API key and base URL for a provider.
+// Checks the session providers map first, then falls back to environment variables.
 func (s *Session) resolveCredentials(prov string) (apiKey, baseURL string) {
 	s.mu.Lock()
-	defer s.mu.Unlock()
-	if pc, ok := s.providers[prov]; ok {
+	pc, ok := s.providers[prov]
+	s.mu.Unlock()
+	if ok && pc.APIKey != "" {
 		return pc.APIKey, pc.BaseURL
 	}
-	return "", ""
+	return config.EnvCredentials(prov)
 }
 
 // --------------------------------------------------------------------------

internal/bootstrap/boot.go

@@ -91,8 +91,8 @@ func Boot(opts Options) (*Runtime, error) {
 	apiKey, _ := settings.ProviderCredentials(settings.Provider)
 	if apiKey == "" {
 		if opts.NonTTYMode {
-			return nil, fmt.Errorf("api key not set, configure providers in %s",
-				config.SettingsPath(cwd))
+			return nil, fmt.Errorf("api key not set; set %s or configure providers in %s",
+				config.ProviderEnvKey(settings.Provider), config.SettingsPath(cwd))
 		}
 		err := config.RunSetup(cwd, settings, func(prov string) []config.ModelOption {
 			entries := registry.FindByProvider(prov)

internal/bootstrap/subagents.go

@@ -82,12 +82,13 @@ func buildSubAgentTool(deps subAgentDeps) *agentcore.SubAgentTool {
 	return sat
 }
 
-// resolveFromProviders returns credentials for a provider from the map.
+// resolveFromProviders returns credentials for a provider from the map,
+// falling back to standard environment variables.
 func resolveFromProviders(providers map[string]config.ProviderConfig, prov string) (apiKey, baseURL string) {
-	if pc, ok := providers[prov]; ok {
+	if pc, ok := providers[prov]; ok && pc.APIKey != "" {
 		return pc.APIKey, pc.BaseURL
 	}
-	return "", ""
+	return config.EnvCredentials(prov)
 }
 
 // readOnlyTools constructs a read-only tool set for explore/plan sub-agents.

internal/config/settings.go

@@ -50,12 +50,42 @@ type Resolved struct {
 	SearchAPIKey   string
 }
 
+// providerEnvVars maps provider names to their standard environment variable names.
+var providerEnvVars = map[string]struct{ key, base string }{
+	"anthropic": {"ANTHROPIC_API_KEY", ""},
+	"openai":    {"OPENAI_API_KEY", "OPENAI_BASE_URL"},
+	"gemini":    {"GEMINI_API_KEY", ""},
+}
+
 // ProviderCredentials returns API key and base URL for the given provider.
+// It checks the providers map first, then falls back to standard environment variables.
 func (r Resolved) ProviderCredentials(prov string) (apiKey, baseURL string) {
-	if pc, ok := r.Providers[prov]; ok {
+	if pc, ok := r.Providers[prov]; ok && pc.APIKey != "" {
 		return pc.APIKey, pc.BaseURL
 	}
-	return "", ""
+	return EnvCredentials(prov)
+}
+
+// ProviderEnvKey returns the standard environment variable name for a provider's API key.
+func ProviderEnvKey(prov string) string {
+	if ev, ok := providerEnvVars[prov]; ok {
+		return ev.key
+	}
+	return strings.ToUpper(prov) + "_API_KEY"
+}
+
+// EnvCredentials returns API key and base URL from standard environment variables
+// for the given provider (e.g. ANTHROPIC_API_KEY, OPENAI_API_KEY).
+func EnvCredentials(prov string) (apiKey, baseURL string) {
+	envVars, ok := providerEnvVars[prov]
+	if !ok {
+		return "", ""
+	}
+	apiKey = os.Getenv(envVars.key)
+	if envVars.base != "" {
+		baseURL = os.Getenv(envVars.base)
+	}
+	return apiKey, baseURL
 }
 
 // ParseModelID splits "provider/model" into (provider, model).