diff --git a/internal/provider/elevenlabs.go b/internal/provider/elevenlabs.go
new file mode 100644
index 0000000..a36a173
--- /dev/null
+++ b/internal/provider/elevenlabs.go
@@ -0,0 +1,41 @@
+package provider
+
+// ElevenLabsProvider implements Provider for ElevenLabs services (transcription only)
+type ElevenLabsProvider struct{}
+
+func (p *ElevenLabsProvider) Name() string {
+	return "elevenlabs"
+}
+
+func (p *ElevenLabsProvider) RequiresAPIKey() bool {
+	return true
+}
+
+func (p *ElevenLabsProvider) ValidateAPIKey(key string) bool {
+	// ElevenLabs API keys don't have a consistent prefix, just check non-empty
+	return len(key) > 0
+}
+
+func (p *ElevenLabsProvider) SupportsTranscription() bool {
+	return true
+}
+
+func (p *ElevenLabsProvider) SupportsLLM() bool {
+	return false
+}
+
+func (p *ElevenLabsProvider) DefaultTranscriptionModel() string {
+	return "scribe_v1"
+}
+
+func (p *ElevenLabsProvider) DefaultLLMModel() string {
+	return ""
+}
+
+func (p *ElevenLabsProvider) TranscriptionModels() []string {
+	return []string{"scribe_v1", "scribe_v2"}
+}
+
+func (p *ElevenLabsProvider) LLMModels() []string {
+	return nil
+}
diff --git a/internal/provider/groq.go b/internal/provider/groq.go
new file mode 100644
index 0000000..77cc4c6
--- /dev/null
+++ b/internal/provider/groq.go
@@ -0,0 +1,42 @@
+package provider
+
+import "strings"
+
+// GroqProvider implements Provider for Groq services
+type GroqProvider struct{}
+
+func (p *GroqProvider) Name() string {
+	return "groq"
+}
+
+func (p *GroqProvider) RequiresAPIKey() bool {
+	return true
+}
+
+func (p *GroqProvider) ValidateAPIKey(key string) bool {
+	return strings.HasPrefix(key, "gsk_")
+}
+
+func (p *GroqProvider) SupportsTranscription() bool {
+	return true
+}
+
+func (p *GroqProvider) SupportsLLM() bool {
+	return true
+}
+
+func (p *GroqProvider) DefaultTranscriptionModel() string {
+	return "whisper-large-v3-turbo"
+}
+
+func (p *GroqProvider) DefaultLLMModel() string {
+	return "llama-3.3-70b-versatile"
+}
+
+func (p *GroqProvider) TranscriptionModels() []string {
+	return []string{"whisper-large-v3", "whisper-large-v3-turbo"}
+}
+
+func (p *GroqProvider) LLMModels() []string {
+	return []string{"llama-3.3-70b-versatile", "llama-3.1-8b-instant", "mixtral-8x7b-32768"}
+}
diff --git a/internal/provider/mistral.go b/internal/provider/mistral.go
new file mode 100644
index 0000000..c080701
--- /dev/null
+++ b/internal/provider/mistral.go
@@ -0,0 +1,41 @@
+package provider
+
+// MistralProvider implements Provider for Mistral services (transcription only)
+type MistralProvider struct{}
+
+func (p *MistralProvider) Name() string {
+	return "mistral"
+}
+
+func (p *MistralProvider) RequiresAPIKey() bool {
+	return true
+}
+
+func (p *MistralProvider) ValidateAPIKey(key string) bool {
+	// Mistral API keys don't have a consistent prefix, just check non-empty
+	return len(key) > 0
+}
+
+func (p *MistralProvider) SupportsTranscription() bool {
+	return true
+}
+
+func (p *MistralProvider) SupportsLLM() bool {
+	return false
+}
+
+func (p *MistralProvider) DefaultTranscriptionModel() string {
+	return "voxtral-mini-latest"
+}
+
+func (p *MistralProvider) DefaultLLMModel() string {
+	return ""
+}
+
+func (p *MistralProvider) TranscriptionModels() []string {
+	return []string{"voxtral-mini-latest", "voxtral-mini-2507"}
+}
+
+func (p *MistralProvider) LLMModels() []string {
+	return nil
+}
diff --git a/internal/provider/openai.go b/internal/provider/openai.go
new file mode 100644
index 0000000..318ba30
--- /dev/null
+++ b/internal/provider/openai.go
@@ -0,0 +1,42 @@
+package provider
+
+import "strings"
+
+// OpenAIProvider implements Provider for OpenAI services
+type OpenAIProvider struct{}
+
+func (p *OpenAIProvider) Name() string {
+	return "openai"
+}
+
+func (p *OpenAIProvider) RequiresAPIKey() bool {
+	return true
+}
+
+func (p *OpenAIProvider) ValidateAPIKey(key string) bool {
+	return strings.HasPrefix(key, "sk-")
+}
+
+func (p *OpenAIProvider) SupportsTranscription() bool {
+	return true
+}
+
+func (p *OpenAIProvider) SupportsLLM() bool {
+	return true
+}
+
+func (p *OpenAIProvider) DefaultTranscriptionModel() string {
+	return "whisper-1"
+}
+
+func (p *OpenAIProvider) DefaultLLMModel() string {
+	return "gpt-4o-mini"
+}
+
+func (p *OpenAIProvider) TranscriptionModels() []string {
+	return []string{"whisper-1"}
+}
+
+func (p *OpenAIProvider) LLMModels() []string {
+	return []string{"gpt-4o-mini", "gpt-4o", "gpt-4-turbo", "gpt-3.5-turbo"}
+}
diff --git a/internal/provider/provider.go b/internal/provider/provider.go
new file mode 100644
index 0000000..8c5d243
--- /dev/null
+++ b/internal/provider/provider.go
@@ -0,0 +1,69 @@
+package provider
+
+// Provider defines the interface for a transcription/LLM service provider
+type Provider interface {
+	Name() string
+	RequiresAPIKey() bool
+	ValidateAPIKey(key string) bool
+	SupportsTranscription() bool
+	SupportsLLM() bool
+	DefaultTranscriptionModel() string
+	DefaultLLMModel() string
+	TranscriptionModels() []string
+	LLMModels() []string
+}
+
+// ProviderConfig holds configuration for a single provider
+type ProviderConfig struct {
+	APIKey string `toml:"api_key"`
+}
+
+var registry = make(map[string]Provider)
+
+func init() {
+	Register(&OpenAIProvider{})
+	Register(&GroqProvider{})
+	Register(&MistralProvider{})
+	Register(&ElevenLabsProvider{})
+}
+
+// Register adds a provider to the registry
+func Register(p Provider) {
+	registry[p.Name()] = p
+}
+
+// GetProvider returns a provider by name, or nil if not found
+func GetProvider(name string) Provider {
+	return registry[name]
+}
+
+// ListProviders returns all registered provider names
+func ListProviders() []string {
+	names := make([]string, 0, len(registry))
+	for name := range registry {
+		names = append(names, name)
+	}
+	return names
+}
+
+// ListProvidersWithTranscription returns providers that support transcription
+func ListProvidersWithTranscription() []string {
+	var names []string
+	for name, p := range registry {
+		if p.SupportsTranscription() {
+			names = append(names, name)
+		}
+	}
+	return names
+}
+
+// ListProvidersWithLLM returns providers that support LLM
+func ListProvidersWithLLM() []string {
+	var names []string
+	for name, p := range registry {
+		if p.SupportsLLM() {
+			names = append(names, name)
+		}
+	}
+	return names
+}
diff --git a/internal/provider/provider_test.go b/internal/provider/provider_test.go
new file mode 100644
index 0000000..8a69af7
--- /dev/null
+++ b/internal/provider/provider_test.go
@@ -0,0 +1,139 @@
+package provider
+
+import (
+	"slices"
+	"testing"
+)
+
+func TestProviderInterface(t *testing.T) {
+	providers := []struct {
+		name              string
+		hasTranscription  bool
+		hasLLM            bool
+		defaultTransModel string
+		defaultLLMModel   string
+	}{
+		{"openai", true, true, "whisper-1", "gpt-4o-mini"},
+		{"groq", true, true, "whisper-large-v3-turbo", "llama-3.3-70b-versatile"},
+		{"mistral", true, false, "voxtral-mini-latest", ""},
+		{"elevenlabs", true, false, "scribe_v1", ""},
+	}
+
+	for _, tc := range providers {
+		t.Run(tc.name, func(t *testing.T) {
+			p := GetProvider(tc.name)
+			if p == nil {
+				t.Fatalf("GetProvider(%q) returned nil", tc.name)
+			}
+
+			if p.Name() != tc.name {
+				t.Errorf("Name() = %q, want %q", p.Name(), tc.name)
+			}
+
+			if p.SupportsTranscription() != tc.hasTranscription {
+				t.Errorf("SupportsTranscription() = %v, want %v", p.SupportsTranscription(), tc.hasTranscription)
+			}
+
+			if p.SupportsLLM() != tc.hasLLM {
+				t.Errorf("SupportsLLM() = %v, want %v", p.SupportsLLM(), tc.hasLLM)
+			}
+
+			if p.DefaultTranscriptionModel() != tc.defaultTransModel {
+				t.Errorf("DefaultTranscriptionModel() = %q, want %q", p.DefaultTranscriptionModel(), tc.defaultTransModel)
+			}
+
+			if p.DefaultLLMModel() != tc.defaultLLMModel {
+				t.Errorf("DefaultLLMModel() = %q, want %q", p.DefaultLLMModel(), tc.defaultLLMModel)
+			}
+
+			if !p.RequiresAPIKey() {
+				t.Error("RequiresAPIKey() should be true for all providers")
+			}
+
+			if tc.hasTranscription && len(p.TranscriptionModels()) == 0 {
+				t.Error("TranscriptionModels() should not be empty for transcription provider")
+			}
+
+			if tc.hasLLM && len(p.LLMModels()) == 0 {
+				t.Error("LLMModels() should not be empty for LLM provider")
+			}
+		})
+	}
+}
+
+func TestGetProviderNotFound(t *testing.T) {
+	p := GetProvider("nonexistent")
+	if p != nil {
+		t.Errorf("GetProvider(nonexistent) should return nil, got %v", p)
+	}
+}
+
+func TestListProviders(t *testing.T) {
+	providers := ListProviders()
+	expected := []string{"openai", "groq", "mistral", "elevenlabs"}
+
+	for _, name := range expected {
+		if !slices.Contains(providers, name) {
+			t.Errorf("ListProviders() missing %q", name)
+		}
+	}
+}
+
+func TestListProvidersWithTranscription(t *testing.T) {
+	providers := ListProvidersWithTranscription()
+	// All providers support transcription
+	expected := []string{"openai", "groq", "mistral", "elevenlabs"}
+
+	for _, name := range expected {
+		if !slices.Contains(providers, name) {
+			t.Errorf("ListProvidersWithTranscription() missing %q", name)
+		}
+	}
+}
+
+func TestListProvidersWithLLM(t *testing.T) {
+	providers := ListProvidersWithLLM()
+	expected := []string{"openai", "groq"}
+
+	for _, name := range expected {
+		if !slices.Contains(providers, name) {
+			t.Errorf("ListProvidersWithLLM() missing %q", name)
+		}
+	}
+
+	// Mistral and ElevenLabs should NOT be in the list
+	notExpected := []string{"mistral", "elevenlabs"}
+	for _, name := range notExpected {
+		if slices.Contains(providers, name) {
+			t.Errorf("ListProvidersWithLLM() should not include %q", name)
+		}
+	}
+}
+
+func TestValidateAPIKey(t *testing.T) {
+	tests := []struct {
+		provider string
+		key      string
+		valid    bool
+	}{
+		{"openai", "sk-abc123", true},
+		{"openai", "invalid", false},
+		{"openai", "", false},
+		{"groq", "gsk_abc123", true},
+		{"groq", "invalid", false},
+		{"groq", "", false},
+		{"mistral", "any-non-empty", true},
+		{"mistral", "", false},
+		{"elevenlabs", "any-non-empty", true},
+		{"elevenlabs", "", false},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.provider+"_"+tc.key, func(t *testing.T) {
+			p := GetProvider(tc.provider)
+			if p.ValidateAPIKey(tc.key) != tc.valid {
+				t.Errorf("ValidateAPIKey(%q) = %v, want %v", tc.key, !tc.valid, tc.valid)
+			}
+		})
+	}
+}
diff --git a/progress.txt b/progress.txt
new file mode 100644
index 0000000..c4100d7
--- /dev/null
+++ b/progress.txt
@@ -0,0 +1,17 @@
+# Ralph Progress Log
+Started: Sat Jan 31 08:30:51 PM CET 2026
+---
+
+## Task 1: Create Provider interface and registry - COMPLETE
+
+Created internal/provider package with:
+- Provider interface with all required methods
+- ProviderConfig struct for API key storage
+- 4 provider implementations: OpenAI, Groq, Mistral, ElevenLabs
+- Registry with GetProvider(), ListProviders(), ListProvidersWithLLM(), ListProvidersWithTranscription()
+- Comprehensive tests (all passing)
+
+Key decisions:
+- OpenAI and Groq support both transcription + LLM
+- Mistral and ElevenLabs are transcription-only
+- ValidateAPIKey checks prefix for OpenAI (sk-) and Groq (gsk_), accepts any non-empty for others
diff --git a/tasks/prd.jsonc b/tasks/prd.jsonc
index aa3da2b..9cd89b5 100644
--- a/tasks/prd.jsonc
+++ b/tasks/prd.jsonc
@@ -22,7 +22,7 @@
         "Capability methods return correct values",
         "Typecheck passes"
       ],
-      "passes": false
+      "passes": true
     },
     {
       "title": "Refactor config to unified provider structure",