diff --git a/cmd/picoclaw/cmd_gateway.go b/cmd/picoclaw/cmd_gateway.go
index 28ef76ad3..c138f837e 100644
--- a/cmd/picoclaw/cmd_gateway.go
+++ b/cmd/picoclaw/cmd_gateway.go
@@ -10,7 +10,6 @@ import (
 	"os"
 	"os/signal"
 	"path/filepath"
-	"strings"
 	"time"
 
 	"github.com/sipeed/picoclaw/pkg/agent"
@@ -25,7 +24,6 @@ import (
 	"github.com/sipeed/picoclaw/pkg/providers"
 	"github.com/sipeed/picoclaw/pkg/state"
 	"github.com/sipeed/picoclaw/pkg/tools"
-	"github.com/sipeed/picoclaw/pkg/voice"
 )
 
 func gatewayCmd() {
@@ -121,38 +119,35 @@ func gatewayCmd() {
 	// Inject channel manager into agent loop for command handling
 	agentLoop.SetChannelManager(channelManager)
 
-	var transcriber *voice.GroqTranscriber
-	groqAPIKey := cfg.Providers.Groq.APIKey
-	if groqAPIKey == "" {
-		for _, mc := range cfg.ModelList {
-			if strings.HasPrefix(mc.Model, "groq/") && mc.APIKey != "" {
-				groqAPIKey = mc.APIKey
-				break
-			}
-		}
-	}
-	if groqAPIKey != "" {
-		transcriber = voice.NewGroqTranscriber(groqAPIKey)
-		logger.InfoC("voice", "Groq voice transcription enabled")
+	// STT (Speech-to-Text) transcriber setup
+	transcriber := resolveSTTTranscriber(cfg)
+	if transcriber != nil {
+		logger.InfoC("voice", "STT voice transcription enabled")
 	}
 
 	if transcriber != nil {
 		if telegramChannel, ok := channelManager.GetChannel("telegram"); ok {
 			if tc, ok := telegramChannel.(*channels.TelegramChannel); ok {
 				tc.SetTranscriber(transcriber)
-				logger.InfoC("voice", "Groq transcription attached to Telegram channel")
+				logger.InfoC("voice", "STT transcription attached to Telegram channel")
 			}
 		}
 		if discordChannel, ok := channelManager.GetChannel("discord"); ok {
 			if dc, ok := discordChannel.(*channels.DiscordChannel); ok {
 				dc.SetTranscriber(transcriber)
-				logger.InfoC("voice", "Groq transcription attached to Discord channel")
+				logger.InfoC("voice", "STT transcription attached to Discord channel")
 			}
 		}
 		if slackChannel, ok := channelManager.GetChannel("slack"); ok {
 			if sc, ok := slackChannel.(*channels.SlackChannel); ok {
 				sc.SetTranscriber(transcriber)
-				logger.InfoC("voice", "Groq transcription attached to Slack channel")
+				logger.InfoC("voice", "STT transcription attached to Slack channel")
+			}
+		}
+		if onebotChannel, ok := channelManager.GetChannel("onebot"); ok {
+			if oc, ok := onebotChannel.(*channels.OneBotChannel); ok {
+				oc.SetTranscriber(transcriber)
+				logger.InfoC("voice", "STT transcription attached to OneBot channel")
 			}
 		}
 	}
@@ -246,3 +241,14 @@ func setupCronTool(
 
 	return cronService
 }
+
+func getDefaultSTTBase(protocol string) string {
+	switch protocol {
+	case "openai":
+		return "https://api.openai.com/v1"
+	case "groq":
+		return "https://api.groq.com/openai/v1"
+	default:
+		return ""
+	}
+}
diff --git a/cmd/picoclaw/stt_resolution.go b/cmd/picoclaw/stt_resolution.go
new file mode 100644
index 000000000..cc70d71b5
--- /dev/null
+++ b/cmd/picoclaw/stt_resolution.go
@@ -0,0 +1,51 @@
+package main
+
+import (
+	"strings"
+
+	"github.com/sipeed/picoclaw/pkg/config"
+	"github.com/sipeed/picoclaw/pkg/providers"
+	"github.com/sipeed/picoclaw/pkg/voice"
+)
+
+// resolveSTTTranscriber resolves the STT transcriber using a 3-tier fallback strategy:
+// 1. agents.defaults.stt_model → model_list lookup
+// 2. providers.groq.api_key (backward compat)
+// 3. groq/ prefix in model_list (backward compat)
+func resolveSTTTranscriber(cfg *config.Config) voice.Transcriber {
+	// 1. Resolve from agents.defaults.stt_model → model_list lookup
+	if cfg.Agents.Defaults.STTModel != "" {
+		for _, mc := range cfg.ModelList {
+			if mc.ModelName == cfg.Agents.Defaults.STTModel && mc.APIKey != "" {
+				protocol, modelID := providers.ExtractProtocol(mc.Model)
+				apiBase := mc.APIBase
+				if apiBase == "" {
+					apiBase = getDefaultSTTBase(protocol)
+				}
+				return voice.NewOpenAICompatTranscriber(mc.APIKey, apiBase, modelID)
+			}
+		}
+	}
+
+	// 2. Backward compat: providers.groq.api_key
+	if cfg.Providers.Groq.APIKey != "" {
+		return voice.NewOpenAICompatTranscriber(
+			cfg.Providers.Groq.APIKey,
+			"https://api.groq.com/openai/v1",
+			"whisper-large-v3",
+		)
+	}
+
+	// 3. Backward compat: groq/ in model_list (no stt_model set)
+	for _, mc := range cfg.ModelList {
+		if strings.HasPrefix(mc.Model, "groq/") && mc.APIKey != "" {
+			return voice.NewOpenAICompatTranscriber(
+				mc.APIKey,
+				"https://api.groq.com/openai/v1",
+				"whisper-large-v3",
+			)
+		}
+	}
+
+	return nil
+}
diff --git a/cmd/picoclaw/stt_resolution_test.go b/cmd/picoclaw/stt_resolution_test.go
new file mode 100644
index 000000000..3f3f16858
--- /dev/null
+++ b/cmd/picoclaw/stt_resolution_test.go
@@ -0,0 +1,241 @@
+package main
+
+import (
+	"testing"
+
+	"github.com/sipeed/picoclaw/pkg/config"
+	"github.com/sipeed/picoclaw/pkg/voice"
+)
+
+func TestGetDefaultSTTBase(t *testing.T) {
+	tests := []struct {
+		protocol string
+		expected string
+	}{
+		{"openai", "https://api.openai.com/v1"},
+		{"groq", "https://api.groq.com/openai/v1"},
+		{"unknown", ""},
+		{"", ""},
+	}
+	for _, tt := range tests {
+		t.Run(tt.protocol, func(t *testing.T) {
+			if got := getDefaultSTTBase(tt.protocol); got != tt.expected {
+				t.Errorf("getDefaultSTTBase(%q) = %q, want %q", tt.protocol, got, tt.expected)
+			}
+		})
+	}
+}
+
+func TestResolveSTTTranscriber_STTModel(t *testing.T) {
+	cfg := &config.Config{
+		Agents: config.AgentsConfig{
+			Defaults: config.AgentDefaults{
+				STTModel: "whisper",
+			},
+		},
+		ModelList: []config.ModelConfig{
+			{
+				ModelName: "whisper",
+				Model:     "openai/whisper-1",
+				APIKey:    "sk-test",
+			},
+		},
+	}
+
+	tr := resolveSTTTranscriber(cfg)
+	if tr == nil {
+		t.Fatal("expected transcriber, got nil")
+	}
+	if !tr.IsAvailable() {
+		t.Error("expected transcriber to be available")
+	}
+}
+
+func TestResolveSTTTranscriber_STTModelWithAPIBase(t *testing.T) {
+	cfg := &config.Config{
+		Agents: config.AgentsConfig{
+			Defaults: config.AgentDefaults{
+				STTModel: "whisper",
+			},
+		},
+		ModelList: []config.ModelConfig{
+			{
+				ModelName: "whisper",
+				Model:     "openai/whisper-1",
+				APIKey:    "sk-test",
+				APIBase:   "https://custom.api.com/v1",
+			},
+		},
+	}
+
+	tr := resolveSTTTranscriber(cfg)
+	if tr == nil {
+		t.Fatal("expected transcriber, got nil")
+	}
+	// Verify it's the right type and has the right fields
+	oat, ok := tr.(*voice.OpenAICompatTranscriber)
+	if !ok {
+		t.Fatal("expected *voice.OpenAICompatTranscriber")
+	}
+	_ = oat // Can't access unexported fields from test, but the resolution worked
+}
+
+func TestResolveSTTTranscriber_STTModelGroq(t *testing.T) {
+	cfg := &config.Config{
+		Agents: config.AgentsConfig{
+			Defaults: config.AgentDefaults{
+				STTModel: "whisper",
+			},
+		},
+		ModelList: []config.ModelConfig{
+			{
+				ModelName: "whisper",
+				Model:     "groq/whisper-large-v3",
+				APIKey:    "gsk-test",
+			},
+		},
+	}
+
+	tr := resolveSTTTranscriber(cfg)
+	if tr == nil {
+		t.Fatal("expected transcriber, got nil")
+	}
+}
+
+func TestResolveSTTTranscriber_BackwardCompatGroqProvider(t *testing.T) {
+	cfg := &config.Config{
+		Providers: config.ProvidersConfig{
+			Groq: config.ProviderConfig{
+				APIKey: "gsk-test-key",
+			},
+		},
+	}
+
+	tr := resolveSTTTranscriber(cfg)
+	if tr == nil {
+		t.Fatal("expected transcriber, got nil")
+	}
+	if !tr.IsAvailable() {
+		t.Error("expected transcriber to be available")
+	}
+}
+
+func TestResolveSTTTranscriber_BackwardCompatGroqModelList(t *testing.T) {
+	cfg := &config.Config{
+		ModelList: []config.ModelConfig{
+			{
+				ModelName: "groq-llama",
+				Model:     "groq/llama-3.3-70b",
+				APIKey:    "gsk-test-key",
+			},
+		},
+	}
+
+	tr := resolveSTTTranscriber(cfg)
+	if tr == nil {
+		t.Fatal("expected transcriber, got nil")
+	}
+}
+
+func TestResolveSTTTranscriber_NoneAvailable(t *testing.T) {
+	cfg := &config.Config{}
+	tr := resolveSTTTranscriber(cfg)
+	if tr != nil {
+		t.Error("expected nil transcriber when no config available")
+	}
+}
+
+func TestResolveSTTTranscriber_STTModelPriority(t *testing.T) {
+	// stt_model should take priority over providers.groq.api_key
+	cfg := &config.Config{
+		Agents: config.AgentsConfig{
+			Defaults: config.AgentDefaults{
+				STTModel: "whisper",
+			},
+		},
+		ModelList: []config.ModelConfig{
+			{
+				ModelName: "whisper",
+				Model:     "openai/whisper-1",
+				APIKey:    "sk-openai-key",
+			},
+		},
+		Providers: config.ProvidersConfig{
+			Groq: config.ProviderConfig{
+				APIKey: "gsk-groq-key",
+			},
+		},
+	}
+
+	tr := resolveSTTTranscriber(cfg)
+	if tr == nil {
+		t.Fatal("expected transcriber, got nil")
+	}
+	// The transcriber should be from stt_model (OpenAI), not from Groq
+	// We can verify by checking it's available
+	if !tr.IsAvailable() {
+		t.Error("expected transcriber to be available")
+	}
+}
+
+func TestResolveSTTTranscriber_STTModelNotInModelList(t *testing.T) {
+	// stt_model set but not found in model_list, should fall back
+	cfg := &config.Config{
+		Agents: config.AgentsConfig{
+			Defaults: config.AgentDefaults{
+				STTModel: "nonexistent",
+			},
+		},
+		Providers: config.ProvidersConfig{
+			Groq: config.ProviderConfig{
+				APIKey: "gsk-fallback",
+			},
+		},
+	}
+
+	tr := resolveSTTTranscriber(cfg)
+	if tr == nil {
+		t.Fatal("expected transcriber from fallback, got nil")
+	}
+}
+
+func TestResolveSTTTranscriber_LLMEntryNotMatchedAsSTT(t *testing.T) {
+	// A non-groq LLM entry should NOT be matched as STT provider
+	cfg := &config.Config{
+		ModelList: []config.ModelConfig{
+			{
+				ModelName: "gpt4",
+				Model:     "openai/gpt-4o",
+				APIKey:    "sk-test",
+			},
+		},
+	}
+
+	tr := resolveSTTTranscriber(cfg)
+	if tr != nil {
+		t.Error("expected nil - LLM entries should not match as STT providers")
+	}
+}
+
+func TestResolveSTTTranscriber_STTModelNoAPIKey(t *testing.T) {
+	// stt_model found but no API key, should fall back
+	cfg := &config.Config{
+		Agents: config.AgentsConfig{
+			Defaults: config.AgentDefaults{
+				STTModel: "whisper",
+			},
+		},
+		ModelList: []config.ModelConfig{
+			{
+				ModelName: "whisper",
+				Model:     "openai/whisper-1",
+				APIKey:    "",
+			},
+		},
+	}
+
+	tr := resolveSTTTranscriber(cfg)
+	if tr != nil {
+		t.Error("expected nil - model has no API key")
+	}
+}
diff --git a/config/config.example.json b/config/config.example.json
index 77a8c0683..0b4ef7a24 100644
--- a/config/config.example.json
+++ b/config/config.example.json
@@ -4,6 +4,7 @@
       "workspace": "~/.picoclaw/workspace",
       "restrict_to_workspace": true,
       "model": "gpt4",
+      "stt_model": "",
       "max_tokens": 8192,
       "temperature": 0.7,
       "max_tool_iterations": 20
@@ -43,6 +44,12 @@
       "model": "openai/gpt-5.2",
       "api_key": "sk-key2",
       "api_base": "https://api2.example.com/v1"
+    },
+    {
+      "model_name": "whisper",
+      "model": "groq/whisper-large-v3",
+      "api_key": "gsk_xxx",
+      "_comment": "STT model for voice transcription. Set agents.defaults.stt_model to 'whisper' to use."
     }
   ],
   "channels": {
diff --git a/pkg/channels/discord.go b/pkg/channels/discord.go
index 20f3b267c..64983be20 100644
--- a/pkg/channels/discord.go
+++ b/pkg/channels/discord.go
@@ -26,7 +26,7 @@ type DiscordChannel struct {
 	*BaseChannel
 	session     *discordgo.Session
 	config      config.DiscordConfig
-	transcriber *voice.GroqTranscriber
+	transcriber voice.Transcriber
 	ctx         context.Context
 	typingMu    sync.Mutex
 	typingStop  map[string]chan struct{} // chatID → stop signal
@@ -51,7 +51,7 @@ func NewDiscordChannel(cfg config.DiscordConfig, bus *bus.MessageBus) (*DiscordC
 	}, nil
 }
 
-func (c *DiscordChannel) SetTranscriber(transcriber *voice.GroqTranscriber) {
+func (c *DiscordChannel) SetTranscriber(transcriber voice.Transcriber) {
 	c.transcriber = transcriber
 }
 
diff --git a/pkg/channels/onebot.go b/pkg/channels/onebot.go
index cee8ad9d3..ef33631ae 100644
--- a/pkg/channels/onebot.go
+++ b/pkg/channels/onebot.go
@@ -35,7 +35,7 @@ type OneBotChannel struct {
 	selfID          int64
 	pending         map[string]chan json.RawMessage
 	pendingMu       sync.Mutex
-	transcriber     *voice.GroqTranscriber
+	transcriber     voice.Transcriber
 	lastMessageID   sync.Map
 	pendingEmojiMsg sync.Map
 }
@@ -111,7 +111,7 @@ func NewOneBotChannel(cfg config.OneBotConfig, messageBus *bus.MessageBus) (*One
 	}, nil
 }
 
-func (c *OneBotChannel) SetTranscriber(transcriber *voice.GroqTranscriber) {
+func (c *OneBotChannel) SetTranscriber(transcriber voice.Transcriber) {
 	c.transcriber = transcriber
 }
 
diff --git a/pkg/channels/slack.go b/pkg/channels/slack.go
index f7359cd6d..1272f82a6 100644
--- a/pkg/channels/slack.go
+++ b/pkg/channels/slack.go
@@ -26,7 +26,7 @@ type SlackChannel struct {
 	socketClient *socketmode.Client
 	botUserID    string
 	teamID       string
-	transcriber  *voice.GroqTranscriber
+	transcriber  voice.Transcriber
 	ctx          context.Context
 	cancel       context.CancelFunc
 	pendingAcks  sync.Map
@@ -59,7 +59,7 @@ func NewSlackChannel(cfg config.SlackConfig, messageBus *bus.MessageBus) (*Slack
 	}, nil
 }
 
-func (c *SlackChannel) SetTranscriber(transcriber *voice.GroqTranscriber) {
+func (c *SlackChannel) SetTranscriber(transcriber voice.Transcriber) {
 	c.transcriber = transcriber
 }
 
diff --git a/pkg/channels/telegram.go b/pkg/channels/telegram.go
index a0a1c8d0a..c5ef91173 100644
--- a/pkg/channels/telegram.go
+++ b/pkg/channels/telegram.go
@@ -29,7 +29,7 @@ type TelegramChannel struct {
 	commands     TelegramCommander
 	config       *config.Config
 	chatIDs      map[string]int64
-	transcriber  *voice.GroqTranscriber
+	transcriber  voice.Transcriber
 	placeholders sync.Map // chatID -> messageID
 	stopThinking sync.Map // chatID -> thinkingCancel
 }
@@ -86,7 +86,7 @@ func NewTelegramChannel(cfg *config.Config, bus *bus.MessageBus) (*TelegramChann
 	}, nil
 }
 
-func (c *TelegramChannel) SetTranscriber(transcriber *voice.GroqTranscriber) {
+func (c *TelegramChannel) SetTranscriber(transcriber voice.Transcriber) {
 	c.transcriber = transcriber
 }
 
diff --git a/pkg/config/config.go b/pkg/config/config.go
index 20556011a..ae1efb37c 100644
--- a/pkg/config/config.go
+++ b/pkg/config/config.go
@@ -177,6 +177,7 @@ type AgentDefaults struct {
 	MaxTokens           int      `json:"max_tokens"                      env:"PICOCLAW_AGENTS_DEFAULTS_MAX_TOKENS"`
 	Temperature         *float64 `json:"temperature,omitempty"           env:"PICOCLAW_AGENTS_DEFAULTS_TEMPERATURE"`
 	MaxToolIterations   int      `json:"max_tool_iterations"             env:"PICOCLAW_AGENTS_DEFAULTS_MAX_TOOL_ITERATIONS"`
+	STTModel            string   `json:"stt_model,omitempty"             env:"PICOCLAW_AGENTS_DEFAULTS_STT_MODEL"`
 }
 
 type ChannelsConfig struct {
diff --git a/pkg/voice/transcriber.go b/pkg/voice/transcriber.go
index f973e77fe..13c923017 100644
--- a/pkg/voice/transcriber.go
+++ b/pkg/voice/transcriber.go
@@ -16,9 +16,15 @@ import (
 	"github.com/sipeed/picoclaw/pkg/utils"
 )
 
-type GroqTranscriber struct {
+type Transcriber interface {
+	Transcribe(ctx context.Context, audioFilePath string) (*TranscriptionResponse, error)
+	IsAvailable() bool
+}
+
+type OpenAICompatTranscriber struct {
 	apiKey     string
 	apiBase    string
+	model      string
 	httpClient *http.Client
 }
 
@@ -28,20 +34,20 @@ type TranscriptionResponse struct {
 	Duration float64 `json:"duration,omitempty"`
 }
 
-func NewGroqTranscriber(apiKey string) *GroqTranscriber {
-	logger.DebugCF("voice", "Creating Groq transcriber", map[string]any{"has_api_key": apiKey != ""})
+func NewOpenAICompatTranscriber(apiKey, apiBase, model string) *OpenAICompatTranscriber {
+	logger.DebugCF("voice", "Creating STT transcriber", map[string]any{"has_api_key": apiKey != ""})
 
-	apiBase := "https://api.groq.com/openai/v1"
-	return &GroqTranscriber{
+	return &OpenAICompatTranscriber{
 		apiKey:  apiKey,
 		apiBase: apiBase,
+		model:   model,
 		httpClient: &http.Client{
 			Timeout: 60 * time.Second,
 		},
 	}
 }
 
-func (t *GroqTranscriber) Transcribe(ctx context.Context, audioFilePath string) (*TranscriptionResponse, error) {
+func (t *OpenAICompatTranscriber) Transcribe(ctx context.Context, audioFilePath string) (*TranscriptionResponse, error) {
 	logger.InfoCF("voice", "Starting transcription", map[string]any{"audio_file": audioFilePath})
 
 	audioFile, err := os.Open(audioFilePath)
@@ -79,7 +85,7 @@ func (t *GroqTranscriber) Transcribe(ctx context.Context, audioFilePath string)
 
 	logger.DebugCF("voice", "File copied to request", map[string]any{"bytes_copied": copied})
 
-	if err = writer.WriteField("model", "whisper-large-v3"); err != nil {
+	if err = writer.WriteField("model", t.model); err != nil {
 		logger.ErrorCF("voice", "Failed to write model field", map[string]any{"error": err})
 		return nil, fmt.Errorf("failed to write model field: %w", err)
 	}
@@ -104,7 +110,7 @@ func (t *GroqTranscriber) Transcribe(ctx context.Context, audioFilePath string)
 	req.Header.Set("Content-Type", writer.FormDataContentType())
 	req.Header.Set("Authorization", "Bearer "+t.apiKey)
 
-	logger.DebugCF("voice", "Sending transcription request to Groq API", map[string]any{
+	logger.DebugCF("voice", "Sending transcription request to STT API", map[string]any{
 		"url":                url,
 		"request_size_bytes": requestBody.Len(),
 		"file_size_bytes":    fileInfo.Size(),
@@ -131,7 +137,7 @@ func (t *GroqTranscriber) Transcribe(ctx context.Context, audioFilePath string)
 		return nil, fmt.Errorf("API error (status %d): %s", resp.StatusCode, string(body))
 	}
 
-	logger.DebugCF("voice", "Received response from Groq API", map[string]any{
+	logger.DebugCF("voice", "Received response from STT API", map[string]any{
 		"status_code":         resp.StatusCode,
 		"response_size_bytes": len(body),
 	})
@@ -152,7 +158,7 @@ func (t *GroqTranscriber) Transcribe(ctx context.Context, audioFilePath string)
 	return &result, nil
 }
 
-func (t *GroqTranscriber) IsAvailable() bool {
+func (t *OpenAICompatTranscriber) IsAvailable() bool {
 	available := t.apiKey != ""
 	logger.DebugCF("voice", "Checking transcriber availability", map[string]any{"available": available})
 	return available
diff --git a/pkg/voice/transcriber_test.go b/pkg/voice/transcriber_test.go
new file mode 100644
index 000000000..973f25d05
--- /dev/null
+++ b/pkg/voice/transcriber_test.go
@@ -0,0 +1,117 @@
+package voice
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestNewOpenAICompatTranscriber(t *testing.T) {
+	tr := NewOpenAICompatTranscriber("test-key", "https://api.example.com/v1", "whisper-1")
+	if tr.apiKey != "test-key" {
+		t.Errorf("expected apiKey 'test-key', got %q", tr.apiKey)
+	}
+	if tr.apiBase != "https://api.example.com/v1" {
+		t.Errorf("expected apiBase 'https://api.example.com/v1', got %q", tr.apiBase)
+	}
+	if tr.model != "whisper-1" {
+		t.Errorf("expected model 'whisper-1', got %q", tr.model)
+	}
+}
+
+func TestOpenAICompatTranscriber_IsAvailable(t *testing.T) {
+	tests := []struct {
+		name     string
+		apiKey   string
+		expected bool
+	}{
+		{"with key", "test-key", true},
+		{"empty key", "", false},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			tr := NewOpenAICompatTranscriber(tt.apiKey, "https://example.com", "model")
+			if got := tr.IsAvailable(); got != tt.expected {
+				t.Errorf("IsAvailable() = %v, want %v", got, tt.expected)
+			}
+		})
+	}
+}
+
+func TestOpenAICompatTranscriber_ImplementsInterface(t *testing.T) {
+	var _ Transcriber = (*OpenAICompatTranscriber)(nil)
+}
+
+func TestOpenAICompatTranscriber_Transcribe(t *testing.T) {
+	// Create a mock HTTP server
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		// Verify it hits the right endpoint
+		if r.URL.Path != "/audio/transcriptions" {
+			t.Errorf("expected path /audio/transcriptions, got %s", r.URL.Path)
+		}
+		// Verify auth header
+		if r.Header.Get("Authorization") != "Bearer test-key" {
+			t.Errorf("unexpected auth header: %s", r.Header.Get("Authorization"))
+		}
+		// Verify it's multipart
+		if err := r.ParseMultipartForm(10 << 20); err != nil {
+			t.Errorf("failed to parse multipart form: %v", err)
+		}
+		// Verify model field
+		if model := r.FormValue("model"); model != "whisper-1" {
+			t.Errorf("expected model 'whisper-1', got %q", model)
+		}
+		// Return mock response
+		resp := TranscriptionResponse{
+			Text:     "Hello world",
+			Language: "en",
+			Duration: 1.5,
+		}
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(resp)
+	}))
+	defer server.Close()
+
+	tr := NewOpenAICompatTranscriber("test-key", server.URL, "whisper-1")
+
+	// Create a temp audio file
+	tmpDir := t.TempDir()
+	audioFile := filepath.Join(tmpDir, "test.ogg")
+	if err := os.WriteFile(audioFile, []byte("fake audio data"), 0644); err != nil {
+		t.Fatalf("failed to create temp file: %v", err)
+	}
+
+	result, err := tr.Transcribe(context.Background(), audioFile)
+	if err != nil {
+		t.Fatalf("Transcribe() error: %v", err)
+	}
+	if result.Text != "Hello world" {
+		t.Errorf("expected text 'Hello world', got %q", result.Text)
+	}
+	if result.Language != "en" {
+		t.Errorf("expected language 'en', got %q", result.Language)
+	}
+}
+
+func TestOpenAICompatTranscriber_TranscribeError(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusUnauthorized)
+		w.Write([]byte(`{"error": "invalid api key"}`))
+	}))
+	defer server.Close()
+
+	tr := NewOpenAICompatTranscriber("bad-key", server.URL, "whisper-1")
+
+	tmpDir := t.TempDir()
+	audioFile := filepath.Join(tmpDir, "test.ogg")
+	os.WriteFile(audioFile, []byte("fake audio data"), 0644)
+
+	_, err := tr.Transcribe(context.Background(), audioFile)
+	if err == nil {
+		t.Fatal("expected error, got nil")
+	}
+}