feat(chat,seahorse): persist and display model_name across history (#2897)

* feat(chat,seahorse): persist and display model_name across history

* test(seahorse): fix lint regressions in repair coverage

* fix(pico): preserve model_name in live updates

* fix(pico): preserve model_name through live stream wrappers

pkg/agent/agent.go

@@ -600,6 +600,12 @@ func (al *AgentLoop) runAgentLoop(
 			Content:      result.finalContent,
 			ContextUsage: computeContextUsage(agent, opts.Dispatch.SessionKey),
 		}
+		if modelName := strings.TrimSpace(result.modelName); modelName != "" {
+			if msg.Context.Raw == nil {
+				msg.Context.Raw = make(map[string]string, 1)
+			}
+			msg.Context.Raw["model_name"] = modelName
+		}
 		markFinalOutbound(&msg)
 		al.bus.PublishOutbound(ctx, msg)
 	}

pkg/agent/agent_outbound.go

@@ -102,7 +102,10 @@ func (al *AgentLoop) targetReasoningChannelID(channelName string) (chatID string
 	return ""
 }
 
-func (al *AgentLoop) publishPicoReasoning(ctx context.Context, reasoningContent, chatID, sessionKey string) {
+func (al *AgentLoop) publishPicoReasoning(
+	ctx context.Context,
+	reasoningContent, chatID, sessionKey, modelName string,
+) {
 	if reasoningContent == "" || chatID == "" {
 		return
 	}
@@ -114,13 +117,16 @@ func (al *AgentLoop) publishPicoReasoning(ctx context.Context, reasoningContent,
 	pubCtx, pubCancel := context.WithTimeout(ctx, 5*time.Second)
 	defer pubCancel()
 
+	raw := map[string]string{metadataKeyMessageKind: messageKindThought}
+	if trimmedModelName := strings.TrimSpace(modelName); trimmedModelName != "" {
+		raw["model_name"] = trimmedModelName
+	}
+
 	if err := al.bus.PublishOutbound(pubCtx, bus.OutboundMessage{
 		Context: bus.InboundContext{
 			Channel: "pico",
 			ChatID:  chatID,
-			Raw: map[string]string{
-				metadataKeyMessageKind: messageKindThought,
-			},
+			Raw:     raw,
 		},
 		SessionKey: sessionKey,
 		Content:    reasoningContent,
@@ -143,6 +149,7 @@ func (al *AgentLoop) publishPicoReasoning(ctx context.Context, reasoningContent,
 func (al *AgentLoop) publishPicoToolCallInterim(
 	ctx context.Context,
 	ts *turnState,
+	modelName string,
 	reasoningContent string,
 	content string,
 	toolCalls []providers.ToolCall,
@@ -155,7 +162,14 @@ func (al *AgentLoop) publishPicoToolCallInterim(
 		pubCtx, pubCancel := context.WithTimeout(ctx, 3*time.Second)
 		err := al.bus.PublishOutbound(
 			pubCtx,
-			outboundMessageForTurnWithKind(ts, reasoningContent, messageKindThought),
+			outboundMessageForTurnWithOptions(
+				ts,
+				reasoningContent,
+				outboundTurnMessageOptions{
+					kind:      messageKindThought,
+					modelName: modelName,
+				},
+			),
 		)
 		pubCancel()
 		if err != nil && !errors.Is(err, context.DeadlineExceeded) &&
@@ -182,7 +196,12 @@ func (al *AgentLoop) publishPicoToolCallInterim(
 
 	if strings.TrimSpace(content) != "" && !duplicateToolCallContent {
 		pubCtx, pubCancel := context.WithTimeout(ctx, 3*time.Second)
-		err := al.bus.PublishOutbound(pubCtx, outboundMessageForTurn(ts, content))
+		err := al.bus.PublishOutbound(
+			pubCtx,
+			outboundMessageForTurnWithOptions(ts, content, outboundTurnMessageOptions{
+				modelName: modelName,
+			}),
+		)
 		pubCancel()
 		if err != nil && !errors.Is(err, context.DeadlineExceeded) &&
 			!errors.Is(err, context.Canceled) &&
@@ -209,11 +228,13 @@ func (al *AgentLoop) publishPicoToolCallInterim(
 		return
 	}
 
-	msg := outboundMessageForTurnWithKind(ts, "", messageKindToolCalls)
-	if msg.Context.Raw == nil {
-		msg.Context.Raw = map[string]string{}
-	}
-	msg.Context.Raw[metadataKeyToolCalls] = string(rawToolCalls)
+	msg := outboundMessageForTurnWithOptions(ts, "", outboundTurnMessageOptions{
+		kind:      messageKindToolCalls,
+		modelName: modelName,
+		raw: map[string]string{
+			metadataKeyToolCalls: string(rawToolCalls),
+		},
+	})
 
 	pubCtx, pubCancel := context.WithTimeout(ctx, 3*time.Second)
 	err = al.bus.PublishOutbound(pubCtx, msg)

pkg/agent/agent_test.go

@@ -312,7 +312,7 @@ func TestPublishPicoReasoningIncludesSessionKey(t *testing.T) {
 	defer cleanup()
 	_ = provider
 
-	al.publishPicoReasoning(context.Background(), "reasoning", "pico-chat", "session-1")
+	al.publishPicoReasoning(context.Background(), "reasoning", "pico-chat", "session-1", "")
 
 	select {
 	case outbound := <-msgBus.OutboundChan():

pkg/agent/agent_utils.go

@@ -96,15 +96,46 @@ func markFinalOutbound(msg *bus.OutboundMessage) {
 	msg.Context.Raw[metadataKeyOutboundKind] = outboundKindFinal
 }
 
-func outboundMessageForTurnWithKind(ts *turnState, content, kind string) bus.OutboundMessage {
+type outboundTurnMessageOptions struct {
+	kind      string
+	modelName string
+	raw       map[string]string
+}
+
+func outboundMessageForTurnWithOptions(
+	ts *turnState,
+	content string,
+	opts outboundTurnMessageOptions,
+) bus.OutboundMessage {
 	msg := outboundMessageForTurn(ts, content)
-	if strings.TrimSpace(kind) == "" {
+	trimmedKind := strings.TrimSpace(opts.kind)
+	trimmedModelName := strings.TrimSpace(opts.modelName)
+	rawCount := len(opts.raw)
+	if trimmedKind != "" {
+		rawCount++
+	}
+	if trimmedModelName != "" {
+		rawCount++
+	}
+	if rawCount == 0 {
 		return msg
 	}
+
 	if msg.Context.Raw == nil {
-		msg.Context.Raw = make(map[string]string, 1)
+		msg.Context.Raw = make(map[string]string, rawCount)
+	}
+	if trimmedKind != "" {
+		msg.Context.Raw[metadataKeyMessageKind] = trimmedKind
+	}
+	if trimmedModelName != "" {
+		msg.Context.Raw["model_name"] = trimmedModelName
+	}
+	for key, value := range opts.raw {
+		if strings.TrimSpace(key) == "" {
+			continue
+		}
+		msg.Context.Raw[key] = value
 	}
-	msg.Context.Raw[metadataKeyMessageKind] = kind
 	return msg
 }
 
@@ -521,8 +552,9 @@ func hasMediaRefs(messages []providers.Message) bool {
 
 func sideQuestionModelName(agent *AgentInstance, usedLight bool) string {
 	if usedLight && len(agent.LightCandidates) > 0 {
-		// Use the first light candidate's model
-		return agent.LightCandidates[0].Model
+		if name := resolvedCandidateModelName(agent.LightCandidates, ""); name != "" {
+			return name
+		}
 	}
 	return agent.Model
 }
@@ -538,6 +570,14 @@ func modelNameFromIdentityKey(identityKey string) string {
 	return identityKey
 }
 
+func modelAliasFromCandidateIdentityKey(identityKey string) string {
+	const prefix = "model_name:"
+	if !strings.HasPrefix(identityKey, prefix) {
+		return ""
+	}
+	return strings.TrimSpace(strings.TrimPrefix(identityKey, prefix))
+}
+
 func closeProviderIfStateful(provider providers.LLMProvider) {
 	if stateful, ok := provider.(providers.StatefulProvider); ok {
 		stateful.Close()

pkg/agent/context_seahorse.go

@@ -197,6 +197,7 @@ func providerToSeahorseMessage(msg protocoltypes.Message) seahorse.Message {
 	result := seahorse.Message{
 		Role:             msg.Role,
 		Content:          msg.Content,
+		ModelName:        msg.ModelName,
 		ReasoningContent: msg.ReasoningContent,
 		TokenCount:       tokenizer.EstimateMessageTokens(msg),
 	}
@@ -243,6 +244,7 @@ func seahorseToProviderMessages(result *seahorse.AssembleResult) []protocoltypes
 		pm := protocoltypes.Message{
 			Role:             msg.Role,
 			Content:          msg.Content,
+			ModelName:        msg.ModelName,
 			ReasoningContent: msg.ReasoningContent,
 		}
 

pkg/agent/context_seahorse_test.go

@@ -174,6 +174,7 @@ func TestProviderToSeahorseMessageWithReasoning(t *testing.T) {
 	msg := protocoltypes.Message{
 		Role:             "assistant",
 		Content:          "response text",
+		ModelName:        "gpt-5.4-mini",
 		ReasoningContent: "I thought about this carefully",
 	}
 
@@ -181,6 +182,9 @@ func TestProviderToSeahorseMessageWithReasoning(t *testing.T) {
 	if result.ReasoningContent != "I thought about this carefully" {
 		t.Errorf("ReasoningContent = %q, want 'I thought about this carefully'", result.ReasoningContent)
 	}
+	if result.ModelName != "gpt-5.4-mini" {
+		t.Errorf("ModelName = %q, want %q", result.ModelName, "gpt-5.4-mini")
+	}
 }
 
 func TestSeahorseToProviderMessagesWithReasoning(t *testing.T) {
@@ -189,6 +193,7 @@ func TestSeahorseToProviderMessagesWithReasoning(t *testing.T) {
 			{
 				Role:             "assistant",
 				Content:          "response",
+				ModelName:        "gpt-5.4",
 				ReasoningContent: "thinking process",
 			},
 		},
@@ -201,6 +206,9 @@ func TestSeahorseToProviderMessagesWithReasoning(t *testing.T) {
 	if messages[0].ReasoningContent != "thinking process" {
 		t.Errorf("ReasoningContent = %q, want 'thinking process'", messages[0].ReasoningContent)
 	}
+	if messages[0].ModelName != "gpt-5.4" {
+		t.Errorf("ModelName = %q, want %q", messages[0].ModelName, "gpt-5.4")
+	}
 }
 
 func TestSeahorseToProviderMessages(t *testing.T) {

pkg/agent/model_resolution.go

@@ -75,6 +75,7 @@ func candidateFromModelConfig(
 	return providers.FallbackCandidate{
 		Provider:    protocol,
 		Model:       modelID,
+		DisplayName: strings.TrimSpace(mc.ModelName),
 		RPM:         mc.RPM,
 		IdentityKey: modelConfigIdentityKey(mc),
 	}, true
@@ -147,8 +148,9 @@ func resolveModelCandidate(
 	}
 
 	return providers.FallbackCandidate{
-		Provider: ref.Provider,
-		Model:    ref.Model,
+		Provider:    ref.Provider,
+		Model:       ref.Model,
+		DisplayName: raw,
 	}, true
 }
 
@@ -197,6 +199,18 @@ func resolvedCandidateProvider(candidates []providers.FallbackCandidate, fallbac
 	return fallback
 }
 
+func resolvedCandidateModelName(candidates []providers.FallbackCandidate, fallback string) string {
+	if len(candidates) > 0 {
+		if name := modelAliasFromCandidateIdentityKey(candidates[0].IdentityKey); strings.TrimSpace(name) != "" {
+			return name
+		}
+		if displayName := strings.TrimSpace(candidates[0].DisplayName); displayName != "" {
+			return displayName
+		}
+	}
+	return strings.TrimSpace(fallback)
+}
+
 func resolvedModelConfig(cfg *config.Config, modelName, workspace string) (*config.ModelConfig, error) {
 	if cfg == nil {
 		return nil, fmt.Errorf("config is nil")

pkg/agent/model_resolution_test.go

@@ -7,6 +7,55 @@ import (
 	"github.com/sipeed/picoclaw/pkg/providers"
 )
 
+func TestModelNameFromIdentityKey_LegacyProviderModel(t *testing.T) {
+	if got := modelNameFromIdentityKey("openai/gpt-5.4"); got != "gpt-5.4" {
+		t.Fatalf("modelNameFromIdentityKey() = %q, want %q", got, "gpt-5.4")
+	}
+}
+
+func TestModelNameFromIdentityKey_PreservesNonLegacyIdentity(t *testing.T) {
+	if got := modelNameFromIdentityKey("model_name:primary"); got != "model_name:primary" {
+		t.Fatalf("modelNameFromIdentityKey() = %q, want %q", got, "model_name:primary")
+	}
+}
+
+func TestModelAliasFromCandidateIdentityKey(t *testing.T) {
+	if got := modelAliasFromCandidateIdentityKey("model_name:primary"); got != "primary" {
+		t.Fatalf("modelAliasFromCandidateIdentityKey() = %q, want %q", got, "primary")
+	}
+	if got := modelAliasFromCandidateIdentityKey("openai/gpt-5.4"); got != "" {
+		t.Fatalf("modelAliasFromCandidateIdentityKey() = %q, want empty", got)
+	}
+}
+
+func TestResolvedCandidateModelName_PrefersIdentityAlias(t *testing.T) {
+	got := resolvedCandidateModelName([]providers.FallbackCandidate{
+		{Provider: "openai", Model: "gpt-5.4", IdentityKey: "model_name:primary"},
+	}, "fallback-model")
+	if got != "primary" {
+		t.Fatalf("resolvedCandidateModelName() = %q, want %q", got, "primary")
+	}
+}
+
+func TestResolvedCandidateModelName_DoesNotScanFallbackAliases(t *testing.T) {
+	got := resolvedCandidateModelName([]providers.FallbackCandidate{
+		{Provider: "openai", Model: "gpt-5.4"},
+		{Provider: "openai", Model: "gpt-5.4-mini", IdentityKey: "model_name:fallback"},
+	}, "primary-model")
+	if got != "primary-model" {
+		t.Fatalf("resolvedCandidateModelName() = %q, want %q", got, "primary-model")
+	}
+}
+
+func TestResolvedCandidateModelName_UsesCandidateDisplayName(t *testing.T) {
+	got := resolvedCandidateModelName([]providers.FallbackCandidate{
+		{Provider: "openai", Model: "gpt-5.4", DisplayName: "gpt-5.4-display"},
+	}, "fallback-model")
+	if got != "gpt-5.4-display" {
+		t.Fatalf("resolvedCandidateModelName() = %q, want %q", got, "gpt-5.4-display")
+	}
+}
+
 func TestResolveActiveModelConfig_PrefersCandidateIdentityKey(t *testing.T) {
 	cfg := &config.Config{
 		ModelList: []*config.ModelConfig{

pkg/agent/pipeline_execute.go

@@ -180,7 +180,11 @@ toolLoop:
 							toolFeedbackArgsPreview(toolArgs, toolFeedbackMaxLen),
 						)
 						fbCtx, fbCancel := context.WithTimeout(turnCtx, 3*time.Second)
-						_ = al.bus.PublishOutbound(fbCtx, outboundMessageForTurnWithKind(ts, feedbackMsg, messageKindToolFeedback))
+						_ = al.bus.PublishOutbound(fbCtx, outboundMessageForTurnWithOptions(
+							ts,
+							feedbackMsg,
+							outboundTurnMessageOptions{kind: messageKindToolFeedback},
+						))
 						fbCancel()
 					}
 
@@ -467,7 +471,11 @@ toolLoop:
 				toolFeedbackArgsPreview(toolArgs, toolFeedbackMaxLen),
 			)
 			fbCtx, fbCancel := context.WithTimeout(turnCtx, 3*time.Second)
-			_ = al.bus.PublishOutbound(fbCtx, outboundMessageForTurnWithKind(ts, feedbackMsg, messageKindToolFeedback))
+			_ = al.bus.PublishOutbound(fbCtx, outboundMessageForTurnWithOptions(
+				ts,
+				feedbackMsg,
+				outboundTurnMessageOptions{kind: messageKindToolFeedback},
+			))
 			fbCancel()
 		}
 

pkg/agent/pipeline_finalize.go

@@ -33,6 +33,7 @@ func (p *Pipeline) Finalize(
 		ts.setPhase(TurnPhaseCompleted)
 		return turnResult{
 			finalContent: finalContent,
+			modelName:    exec.llmModelName,
 			status:       turnStatus,
 			followUps:    append([]bus.InboundMessage(nil), ts.followUps...),
 		}, nil
@@ -44,6 +45,7 @@ func (p *Pipeline) Finalize(
 		finalMsg := providers.Message{
 			Role:             "assistant",
 			Content:          finalContent,
+			ModelName:        exec.llmModelName,
 			ReasoningContent: responseReasoningContent(exec.response),
 		}
 		ts.agent.Sessions.AddFullMessage(ts.sessionKey, finalMsg)
@@ -80,24 +82,10 @@ func (p *Pipeline) Finalize(
 	// so the final answer is still delivered outside normal SendResponse.
 	if ((streamErr != nil && !isConfiguredStreamingVisibleError(streamErr)) || exec.streamingFallback) &&
 		!ts.opts.SendResponse && ts.opts.AllowInterimPicoPublish && finalContent != "" {
-		agentID, sessionKey, scope := outboundTurnMetadata(
-			ts.agent.ID,
-			ts.opts.Dispatch.SessionKey,
-			ts.opts.Dispatch.SessionScope,
-		)
-		msg := bus.OutboundMessage{
-			Context: outboundContextFromInbound(
-				ts.opts.Dispatch.InboundContext,
-				ts.opts.Dispatch.Channel(),
-				ts.opts.Dispatch.ChatID(),
-				ts.opts.Dispatch.ReplyToMessageID(),
-			),
-			AgentID:      agentID,
-			SessionKey:   sessionKey,
-			Scope:        scope,
-			Content:      finalContent,
-			ContextUsage: contextUsage,
-		}
+		msg := outboundMessageForTurnWithOptions(ts, finalContent, outboundTurnMessageOptions{
+			modelName: exec.llmModelName,
+		})
+		msg.ContextUsage = contextUsage
 		markFinalOutbound(&msg)
 		_ = al.bus.PublishOutbound(turnCtx, msg)
 	}
@@ -112,6 +100,7 @@ func (p *Pipeline) Finalize(
 	ts.setPhase(TurnPhaseCompleted)
 	return turnResult{
 		finalContent: finalContent,
+		modelName:    exec.llmModelName,
 		status:       turnStatus,
 		followUps:    append([]bus.InboundMessage(nil), ts.followUps...),
 	}, nil

pkg/agent/pipeline_llm.go

@@ -200,6 +200,16 @@ func (p *Pipeline) CallLLM(
 					map[string]any{"agent_id": ts.agent.ID, "iteration": iteration},
 				)
 			}
+			for _, candidate := range exec.activeCandidates {
+				if candidate.StableKey() != fbResult.IdentityKey {
+					continue
+				}
+				exec.llmModelName = resolvedCandidateModelName(
+					[]providers.FallbackCandidate{candidate},
+					exec.llmModelName,
+				)
+				break
+			}
 			return fbResult.Response, nil
 		}
 		return exec.activeProvider.Chat(providerCtx, messagesForCall, toolDefsForCall, exec.llmModel, exec.llmOpts)
@@ -477,7 +487,7 @@ func (p *Pipeline) CallLLM(
 			// Publish pico thoughts before the turn context is canceled at return time.
 			// The async variant can race with turn teardown and intermittently drop the
 			// thought message in CI even though the LLM produced reasoning content.
-			al.publishPicoReasoning(turnCtx, reasoningContent, ts.chatID, ts.sessionKey)
+			al.publishPicoReasoning(turnCtx, reasoningContent, ts.chatID, ts.sessionKey, exec.llmModelName)
 		}
 	} else {
 		go al.handleReasoning(
@@ -564,6 +574,7 @@ func (p *Pipeline) CallLLM(
 	assistantMsg := providers.Message{
 		Role:             "assistant",
 		Content:          exec.response.Content,
+		ModelName:        exec.llmModelName,
 		ReasoningContent: reasoningContent,
 	}
 	for _, tc := range exec.normalizedToolCalls {
@@ -607,6 +618,7 @@ func (p *Pipeline) CallLLM(
 		al.publishPicoToolCallInterim(
 			turnCtx,
 			ts,
+			exec.llmModelName,
 			reasoningContent,
 			exec.response.Content,
 			assistantMsg.ToolCalls,

pkg/agent/pipeline_setup.go

@@ -89,6 +89,11 @@ func (p *Pipeline) SetupTurn(ctx context.Context, ts *turnState) (*turnExecution
 	if usedLight && ts.agent.LightProvider != nil {
 		activeProvider = ts.agent.LightProvider
 	}
+	activeModelName := strings.TrimSpace(ts.agent.Model)
+	if usedLight {
+		activeModelName = strings.TrimSpace(sideQuestionModelName(ts.agent, true))
+	}
+	activeModelName = resolvedCandidateModelName(activeCandidates, activeModelName)
 
 	exec := newTurnExecution(
 		ts.agent,
@@ -106,6 +111,7 @@ func (p *Pipeline) SetupTurn(ctx context.Context, ts *turnState) (*turnExecution
 		activeModel,
 		p.Cfg.Agents.Defaults.Provider,
 	)
+	exec.llmModelName = activeModelName
 	exec.activeProvider = activeProvider
 	exec.usedLight = usedLight
 

pkg/agent/pipeline_streaming.go

@@ -50,9 +50,10 @@ func (p *Pipeline) tryConfiguredStreamingLLM(
 	}
 
 	publisher := &streamingChunkPublisher{
-		streamer: streamer,
-		channel:  ts.channel,
-		chatID:   ts.chatID,
+		streamer:  streamer,
+		channel:   ts.channel,
+		chatID:    ts.chatID,
+		modelName: exec.llmModelName,
 	}
 
 	logger.DebugCF("agent", "configured streaming enabled", map[string]any{
@@ -371,6 +372,7 @@ type streamingChunkPublisher struct {
 	streamer           bus.Streamer
 	channel            string
 	chatID             string
+	modelName          string
 	published          bool
 	reasoningPublished bool
 	err                error
@@ -380,6 +382,9 @@ func (p *streamingChunkPublisher) Update(ctx context.Context, accumulated string
 	if p == nil || p.streamer == nil || strings.TrimSpace(accumulated) == "" {
 		return
 	}
+	if setter, ok := p.streamer.(interface{ SetModelName(modelName string) }); ok {
+		setter.SetModelName(p.modelName)
+	}
 	if err := p.streamer.Update(ctx, accumulated); err != nil {
 		p.err = err
 		logger.WarnCF("agent", "stream update failed", map[string]any{
@@ -396,6 +401,9 @@ func (p *streamingChunkPublisher) UpdateReasoning(ctx context.Context, accumulat
 	if p == nil || p.streamer == nil || strings.TrimSpace(accumulated) == "" {
 		return
 	}
+	if setter, ok := p.streamer.(interface{ SetModelName(modelName string) }); ok {
+		setter.SetModelName(p.modelName)
+	}
 	reasoningStreamer, ok := p.streamer.(bus.ReasoningStreamer)
 	if !ok {
 		return
@@ -434,6 +442,9 @@ func (p *streamingChunkPublisher) Finalize(ctx context.Context, content string,
 	if strings.TrimSpace(content) == "" && !p.published {
 		return nil
 	}
+	if setter, ok := p.streamer.(interface{ SetModelName(modelName string) }); ok {
+		setter.SetModelName(p.modelName)
+	}
 	var err error
 	if streamer, ok := p.streamer.(bus.ContextUsageStreamer); ok {
 		err = streamer.FinalizeWithContext(ctx, content, contextUsage)

pkg/agent/pipeline_streaming_test.go

@@ -570,6 +570,9 @@ func TestConfiguredStreamingFinalFlushFailureBeforeVisibleOutputPublishesFallbac
 		if outbound.Content != "stream response" {
 			t.Fatalf("fallback outbound content = %q, want stream response", outbound.Content)
 		}
+		if got := outbound.Context.Raw["model_name"]; got != "test-model" {
+			t.Fatalf("fallback outbound model_name = %q, want %q", got, "test-model")
+		}
 	case <-time.After(time.Second):
 		t.Fatal("expected fallback outbound after invisible final stream flush failure")
 	}

pkg/agent/turn_coord_test.go

@@ -10,6 +10,7 @@ import (
 	"github.com/sipeed/picoclaw/pkg/bus"
 	"github.com/sipeed/picoclaw/pkg/config"
 	"github.com/sipeed/picoclaw/pkg/providers"
+	"github.com/sipeed/picoclaw/pkg/routing"
 	"github.com/sipeed/picoclaw/pkg/session"
 )
 
@@ -37,6 +38,39 @@ func (p *simpleConvProvider) GetDefaultModel() string {
 	return "simple-model"
 }
 
+type sequenceProvider struct {
+	responses []*providers.LLMResponse
+	errors    []error
+	callCount int
+	mu        sync.Mutex
+}
+
+func (p *sequenceProvider) Chat(
+	ctx context.Context,
+	messages []providers.Message,
+	tools []providers.ToolDefinition,
+	model string,
+	opts map[string]any,
+) (*providers.LLMResponse, error) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
+	idx := p.callCount
+	p.callCount++
+
+	if idx < len(p.errors) && p.errors[idx] != nil {
+		return nil, p.errors[idx]
+	}
+	if idx < len(p.responses) && p.responses[idx] != nil {
+		return p.responses[idx], nil
+	}
+	return &providers.LLMResponse{Content: "ok", FinishReason: "stop"}, nil
+}
+
+func (p *sequenceProvider) GetDefaultModel() string {
+	return "sequence-model"
+}
+
 type nativeSearchCaptureProvider struct {
 	lastOpts map[string]any
 }
@@ -271,6 +305,152 @@ func TestPipeline_CallLLM_SimpleResponse(t *testing.T) {
 	}
 }
 
+func TestPipeline_SetupTurn_ModelNameDoesNotUseFallbackAliasBeforeFallback(t *testing.T) {
+	al, agent, cleanup := newTurnCoordTestLoop(t, &simpleConvProvider{})
+	defer cleanup()
+
+	agent.Model = "primary-model"
+	agent.Candidates = []providers.FallbackCandidate{
+		{Provider: "openai", Model: "gpt-5.4"},
+		{Provider: "anthropic", Model: "claude-sonnet", IdentityKey: "model_name:fallback-model"},
+	}
+
+	pipeline := NewPipeline(al)
+	ts := newTurnState(agent, makeTestProcessOpts("test-session"), turnEventScope{
+		turnID:  "turn-1",
+		context: newTurnContext(nil, nil, nil),
+	})
+
+	exec, err := pipeline.SetupTurn(context.Background(), ts)
+	if err != nil {
+		t.Fatalf("SetupTurn failed: %v", err)
+	}
+	if exec.llmModelName != "primary-model" {
+		t.Fatalf("exec.llmModelName = %q, want %q", exec.llmModelName, "primary-model")
+	}
+}
+
+func TestPipeline_CallLLM_UsesSuccessfulFallbackIdentityAlias(t *testing.T) {
+	provider := &sequenceProvider{
+		errors: []error{
+			errors.New("status: 429 - rate limit exceeded"),
+			nil,
+		},
+		responses: []*providers.LLMResponse{
+			nil,
+			{Content: "fallback answer", FinishReason: "stop"},
+		},
+	}
+	al, agent, cleanup := newTurnCoordTestLoop(t, provider)
+	defer cleanup()
+
+	agent.Model = "primary-model"
+	agent.Candidates = []providers.FallbackCandidate{
+		{Provider: "openai", Model: "gpt-5.4", IdentityKey: "model_name:primary"},
+		{Provider: "openai", Model: "gpt-5.4", IdentityKey: "model_name:secondary"},
+	}
+	al.fallback = providers.NewFallbackChain(providers.NewCooldownTracker(), nil)
+
+	pipeline := NewPipeline(al)
+	ts := newTurnState(agent, makeTestProcessOpts("test-session"), turnEventScope{
+		turnID:  "turn-1",
+		context: newTurnContext(nil, nil, nil),
+	})
+
+	exec, err := pipeline.SetupTurn(context.Background(), ts)
+	if err != nil {
+		t.Fatalf("SetupTurn failed: %v", err)
+	}
+
+	ctrl, err := pipeline.CallLLM(context.Background(), context.Background(), ts, exec, 1)
+	if err != nil {
+		t.Fatalf("CallLLM failed: %v", err)
+	}
+	if ctrl != ControlBreak {
+		t.Fatalf("expected ControlBreak, got %v", ctrl)
+	}
+	if exec.llmModelName != "secondary" {
+		t.Fatalf("exec.llmModelName = %q, want %q", exec.llmModelName, "secondary")
+	}
+}
+
+func TestPipeline_CallLLM_UsesSuccessfulFallbackDisplayNameWithoutAlias(t *testing.T) {
+	provider := &sequenceProvider{
+		errors: []error{
+			errors.New("status: 429 - rate limit exceeded"),
+			nil,
+		},
+		responses: []*providers.LLMResponse{
+			nil,
+			{Content: "fallback answer", FinishReason: "stop"},
+		},
+	}
+	al, agent, cleanup := newTurnCoordTestLoop(t, provider)
+	defer cleanup()
+
+	agent.Model = "primary-model"
+	agent.Candidates = []providers.FallbackCandidate{
+		{Provider: "openai", Model: "gpt-5.4", IdentityKey: "model_name:primary", DisplayName: "primary-model"},
+		{Provider: "anthropic", Model: "claude-sonnet", DisplayName: "anthropic/claude-sonnet"},
+	}
+	al.fallback = providers.NewFallbackChain(providers.NewCooldownTracker(), nil)
+
+	pipeline := NewPipeline(al)
+	ts := newTurnState(agent, makeTestProcessOpts("test-session"), turnEventScope{
+		turnID:  "turn-1",
+		context: newTurnContext(nil, nil, nil),
+	})
+
+	exec, err := pipeline.SetupTurn(context.Background(), ts)
+	if err != nil {
+		t.Fatalf("SetupTurn failed: %v", err)
+	}
+
+	ctrl, err := pipeline.CallLLM(context.Background(), context.Background(), ts, exec, 1)
+	if err != nil {
+		t.Fatalf("CallLLM failed: %v", err)
+	}
+	if ctrl != ControlBreak {
+		t.Fatalf("expected ControlBreak, got %v", ctrl)
+	}
+	if exec.llmModelName != "anthropic/claude-sonnet" {
+		t.Fatalf("exec.llmModelName = %q, want %q", exec.llmModelName, "anthropic/claude-sonnet")
+	}
+}
+
+func TestPipeline_SetupTurn_UsesLightCandidateDisplayName(t *testing.T) {
+	al, agent, cleanup := newTurnCoordTestLoop(t, &simpleConvProvider{})
+	defer cleanup()
+
+	agent.Model = "primary-model"
+	agent.Candidates = []providers.FallbackCandidate{
+		{Provider: "openai", Model: "gpt-5.4", IdentityKey: "model_name:primary", DisplayName: "primary-model"},
+	}
+	agent.LightCandidates = []providers.FallbackCandidate{
+		{Provider: "openai", Model: "gpt-5.4-mini", IdentityKey: "model_name:light-model", DisplayName: "light-model"},
+	}
+	agent.Router = routing.New(routing.RouterConfig{LightModel: "light-model", Threshold: 1})
+
+	pipeline := NewPipeline(al)
+	opts := makeTestProcessOpts("test-session")
+	opts.UserMessage = ""
+	ts := newTurnState(agent, opts, turnEventScope{
+		turnID:  "turn-1",
+		context: newTurnContext(nil, nil, nil),
+	})
+
+	exec, err := pipeline.SetupTurn(context.Background(), ts)
+	if err != nil {
+		t.Fatalf("SetupTurn failed: %v", err)
+	}
+	if !exec.usedLight {
+		t.Fatal("expected light routing to be used")
+	}
+	if exec.llmModelName != "light-model" {
+		t.Fatalf("exec.llmModelName = %q, want %q", exec.llmModelName, "light-model")
+	}
+}
+
 func TestRunTurn_FinalizeSaveErrorEmitsErrorTurnEnd(t *testing.T) {
 	al, agent, cleanup := newTurnCoordTestLoop(t, &simpleConvProvider{})
 	defer cleanup()

pkg/agent/turn_state.go

@@ -84,6 +84,7 @@ const (
 
 type turnResult struct {
 	finalContent string
+	modelName    string
 	status       TurnEndStatus
 	followUps    []bus.InboundMessage
 }
@@ -140,6 +141,7 @@ type turnExecution struct {
 	callMessages        []providers.Message
 	providerToolDefs    []providers.ToolDefinition
 	llmModel            string
+	llmModelName        string
 	llmOpts             map[string]any
 	gracefulTerminal    bool
 	useNativeSearch     bool

pkg/channels/interfaces.go

@@ -20,6 +20,17 @@ type MessageEditor interface {
 	EditMessage(ctx context.Context, chatID string, messageID string, content string) error
 }
 
+// MessageEditorWithPayload extends MessageEditor for channels that can update
+// structured message metadata in addition to plain text content.
+type MessageEditorWithPayload interface {
+	EditMessageWithPayload(
+		ctx context.Context,
+		chatID string,
+		messageID string,
+		payload map[string]any,
+	) error
+}
+
 // MessageDeleter — channels that can delete a message by ID.
 type MessageDeleter interface {
 	DeleteMessage(ctx context.Context, chatID string, messageID string) error

pkg/channels/manager.go

@@ -191,6 +191,19 @@ func outboundMessageBypassesPlaceholderEdit(msg bus.OutboundMessage) bool {
 	return strings.EqualFold(kind, "thought") || strings.EqualFold(kind, "tool_calls")
 }
 
+func outboundMessageEditPayload(msg bus.OutboundMessage, content string) map[string]any {
+	payload := map[string]any{
+		"content": content,
+	}
+	if len(msg.Context.Raw) == 0 {
+		return payload
+	}
+	if modelName := strings.TrimSpace(msg.Context.Raw["model_name"]); modelName != "" {
+		payload["model_name"] = modelName
+	}
+	return payload
+}
+
 func outboundMediaChannel(msg bus.OutboundMediaMessage) string {
 	return msg.Context.Channel
 }
@@ -394,7 +407,16 @@ func (m *Manager) preSend(ctx context.Context, name string, msg bus.OutboundMess
 					if deleter, ok := ch.(MessageDeleter); ok {
 						deleter.DeleteMessage(ctx, chatID, entry.id) // best effort
 					} else if editor, ok := ch.(MessageEditor); ok {
-						editor.EditMessage(ctx, chatID, entry.id, msg.Content) // fallback
+						if payloadEditor, ok := ch.(MessageEditorWithPayload); ok {
+							_ = payloadEditor.EditMessageWithPayload(
+								ctx,
+								chatID,
+								entry.id,
+								outboundMessageEditPayload(msg, msg.Content),
+							)
+						} else {
+							editor.EditMessage(ctx, chatID, entry.id, msg.Content) // fallback
+						}
 					}
 				}
 			}
@@ -446,7 +468,18 @@ func (m *Manager) preSend(ctx context.Context, name string, msg bus.OutboundMess
 					trackedContent = prepareToolFeedbackMessageContent(ch, msg.Content)
 					content = InitialAnimatedToolFeedbackContent(trackedContent)
 				}
-				if err := editor.EditMessage(ctx, chatID, entry.id, content); err == nil {
+				err := func() error {
+					if payloadEditor, ok := ch.(MessageEditorWithPayload); ok {
+						return payloadEditor.EditMessageWithPayload(
+							ctx,
+							chatID,
+							entry.id,
+							outboundMessageEditPayload(msg, content),
+						)
+					}
+					return editor.EditMessage(ctx, chatID, entry.id, content)
+				}()
+				if err == nil {
 					trackedChatID := trackedToolFeedbackMessageChatID(ch, chatID, &msg.Context)
 					if tracker, ok := ch.(toolFeedbackMessageTracker); ok && isToolFeedback {
 						tracker.RecordToolFeedbackMessage(trackedChatID, entry.id, trackedContent)
@@ -643,6 +676,18 @@ func reasoningStreamerFrom(streamer bus.Streamer) bus.ReasoningStreamer {
 	return nil
 }
 
+type modelNameStreamer interface {
+	SetModelName(modelName string)
+}
+
+func setStreamerModelName(streamer any, modelName string) {
+	setter, ok := streamer.(modelNameStreamer)
+	if !ok {
+		return
+	}
+	setter.SetModelName(modelName)
+}
+
 // splitMarkerStreamer turns accumulated streaming text containing
 // MessageSplitMarker into separate channel stream messages.
 type splitMarkerStreamer struct {
@@ -654,6 +699,7 @@ type splitMarkerStreamer struct {
 	finalized      bool
 	onFinalize     func(context.Context, string)
 	clearMarker    func()
+	modelName      string
 }
 
 func (s *splitMarkerStreamer) Update(ctx context.Context, content string) error {
@@ -682,6 +728,7 @@ func (s *splitMarkerStreamer) UpdateReasoning(ctx context.Context, content strin
 	if s.reasoning == nil {
 		return nil
 	}
+	setStreamerModelName(s.reasoning, s.modelName)
 	return s.reasoning.UpdateReasoning(ctx, content)
 }
 
@@ -691,9 +738,18 @@ func (s *splitMarkerStreamer) FinalizeReasoning(ctx context.Context, content str
 	if s.reasoning == nil {
 		return nil
 	}
+	setStreamerModelName(s.reasoning, s.modelName)
 	return s.reasoning.FinalizeReasoning(ctx, content)
 }
 
+func (s *splitMarkerStreamer) SetModelName(modelName string) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	s.modelName = strings.TrimSpace(modelName)
+	setStreamerModelName(s.current, s.modelName)
+	setStreamerModelName(s.reasoning, s.modelName)
+}
+
 func (s *splitMarkerStreamer) Cancel(ctx context.Context) {
 	s.mu.Lock()
 	defer s.mu.Unlock()
@@ -772,6 +828,7 @@ func (s *splitMarkerStreamer) ensureCurrentLocked(ctx context.Context) error {
 		return err
 	}
 	s.current = streamer
+	setStreamerModelName(s.current, s.modelName)
 	return nil
 }
 
@@ -856,6 +913,10 @@ func (s *finalizeHookStreamer) FinalizeReasoning(ctx context.Context, content st
 	return nil
 }
 
+func (s *finalizeHookStreamer) SetModelName(modelName string) {
+	setStreamerModelName(s.Streamer, strings.TrimSpace(modelName))
+}
+
 func (s *finalizeHookStreamer) runFinalizeHook(ctx context.Context, content string) {
 	if s.onFinalize != nil {
 		s.onFinalize(ctx, content)

pkg/channels/manager_test.go

@@ -142,11 +142,21 @@ func (m *mockReasoningStreamer) FinalizeReasoning(_ context.Context, content str
 	return nil
 }
 
+type modelTrackingReasoningStreamer struct {
+	mockReasoningStreamer
+	modelNames []string
+}
+
+func (m *modelTrackingReasoningStreamer) SetModelName(modelName string) {
+	m.modelNames = append(m.modelNames, strings.TrimSpace(modelName))
+}
+
 type recordingStreamSegment struct {
 	updates       []string
 	finals        []string
 	finalUsage    *bus.ContextUsage
 	canceledCount int
+	modelNames    []string
 }
 
 func (s *recordingStreamSegment) Update(_ context.Context, content string) error {
@@ -168,6 +178,10 @@ func (s *recordingStreamSegment) Cancel(context.Context) {
 	s.canceledCount++
 }
 
+func (s *recordingStreamSegment) SetModelName(modelName string) {
+	s.modelNames = append(s.modelNames, strings.TrimSpace(modelName))
+}
+
 type mockStreamingChannel struct {
 	mockMessageEditor
 	streamer        Streamer
@@ -2068,6 +2082,42 @@ func TestGetStreamer_PreservesReasoningStreamer(t *testing.T) {
 	}
 }
 
+func TestGetStreamer_PreservesModelNameSetter(t *testing.T) {
+	m := newTestManager()
+	inner := &modelTrackingReasoningStreamer{}
+	ch := &mockStreamingChannel{
+		streamer: inner,
+	}
+	m.channels["test"] = ch
+
+	streamer, ok := m.GetStreamer(context.Background(), "test", "123", "")
+	if !ok {
+		t.Fatal("expected streamer to be available")
+	}
+	setter, ok := streamer.(interface{ SetModelName(modelName string) })
+	if !ok {
+		t.Fatal("manager-wrapped streamer should preserve SetModelName")
+	}
+	setter.SetModelName("gpt-5.4")
+	if err := streamer.Update(context.Background(), "hello"); err != nil {
+		t.Fatalf("Update() error = %v", err)
+	}
+	reasoningStreamer, ok := streamer.(bus.ReasoningStreamer)
+	if !ok {
+		t.Fatal("manager-wrapped streamer should preserve ReasoningStreamer")
+	}
+	setter.SetModelName("gpt-5.4")
+	if err := reasoningStreamer.UpdateReasoning(context.Background(), "thinking"); err != nil {
+		t.Fatalf("UpdateReasoning() error = %v", err)
+	}
+	if len(inner.modelNames) != 2 {
+		t.Fatalf("model name calls = %v, want 2 forwarded calls", inner.modelNames)
+	}
+	if inner.modelNames[0] != "gpt-5.4" || inner.modelNames[1] != "gpt-5.4" {
+		t.Fatalf("model name calls = %v, want both forwarded as gpt-5.4", inner.modelNames)
+	}
+}
+
 func TestGetStreamer_SplitOnMarkerStreamsSeparateSegments(t *testing.T) {
 	m := newTestManager()
 	m.config = &config.Config{
@@ -2188,6 +2238,58 @@ func TestGetStreamer_SplitOnMarkerKeepsReasoningOnInitialStreamer(t *testing.T)
 	}
 }
 
+func TestGetStreamer_SplitOnMarkerPreservesModelNameSetter(t *testing.T) {
+	m := newTestManager()
+	m.config = &config.Config{
+		Agents: config.AgentsConfig{
+			Defaults: config.AgentDefaults{
+				SplitOnMarker: true,
+			},
+		},
+	}
+
+	initial := &modelTrackingReasoningStreamer{}
+	next := &recordingStreamSegment{}
+	callCount := 0
+	ch := &mockStreamingChannel{
+		beginStreamFn: func(context.Context, string) (Streamer, error) {
+			callCount++
+			if callCount == 1 {
+				return initial, nil
+			}
+			return next, nil
+		},
+	}
+	m.channels["test"] = ch
+
+	streamer, ok := m.GetStreamer(context.Background(), "test", "123", "")
+	if !ok {
+		t.Fatal("expected streamer to be available")
+	}
+	setter, ok := streamer.(interface{ SetModelName(modelName string) })
+	if !ok {
+		t.Fatal("split streamer should preserve SetModelName")
+	}
+	setter.SetModelName("gpt-5.4-mini")
+	if err := streamer.Update(context.Background(), "hello<|[SPLIT]|>world"); err != nil {
+		t.Fatalf("Update() error = %v", err)
+	}
+	reasoningStreamer, ok := streamer.(bus.ReasoningStreamer)
+	if !ok {
+		t.Fatal("split streamer should preserve ReasoningStreamer")
+	}
+	if err := reasoningStreamer.UpdateReasoning(context.Background(), "thinking"); err != nil {
+		t.Fatalf("UpdateReasoning() error = %v", err)
+	}
+
+	if len(initial.modelNames) == 0 || initial.modelNames[0] != "gpt-5.4-mini" {
+		t.Fatalf("initial model names = %v, want forwarded gpt-5.4-mini", initial.modelNames)
+	}
+	if len(next.modelNames) == 0 || next.modelNames[0] != "gpt-5.4-mini" {
+		t.Fatalf("next model names = %v, want forwarded gpt-5.4-mini", next.modelNames)
+	}
+}
+
 func TestGetStreamer_FinalizeSeparateMessagesClearsTrackedToolFeedback(t *testing.T) {
 	m := newTestManager()
 	m.config = &config.Config{

pkg/channels/pico/pico.go

@@ -325,6 +325,9 @@ func (c *PicoChannel) Send(ctx context.Context, msg bus.OutboundMessage) ([]stri
 		PayloadKeyContent: content,
 		"message_id":      msgID,
 	}
+	if modelName := strings.TrimSpace(msg.Context.Raw[PayloadKeyModelName]); modelName != "" {
+		payload[PayloadKeyModelName] = modelName
+	}
 	switch {
 	case isThought:
 		payload[PayloadKeyKind] = MessageKindThought
@@ -359,6 +362,15 @@ func (c *PicoChannel) EditMessage(ctx context.Context, chatID string, messageID
 	return c.editMessage(ctx, chatID, messageID, content, nil)
 }
 
+func (c *PicoChannel) EditMessageWithPayload(
+	ctx context.Context,
+	chatID string,
+	messageID string,
+	payload map[string]any,
+) error {
+	return c.editMessagePayload(ctx, chatID, messageID, payload, nil)
+}
+
 // DeleteMessage implements channels.MessageDeleter.
 func (c *PicoChannel) DeleteMessage(ctx context.Context, chatID string, messageID string) error {
 	outMsg := newMessage(TypeMessageDelete, map[string]any{
@@ -419,14 +431,23 @@ func (c *PicoChannel) finalizeTrackedToolFeedbackMessage(
 	ctx context.Context,
 	chatID string,
 	content string,
-	editFn func(context.Context, string, string, string, *bus.ContextUsage) error,
+	editFn func(context.Context, string, string, map[string]any, *bus.ContextUsage) error,
+	payload map[string]any,
 	contextUsage *bus.ContextUsage,
 ) ([]string, bool) {
 	msgID, baseContent, ok := c.takeToolFeedbackMessage(chatID)
 	if !ok || editFn == nil {
 		return nil, false
 	}
-	if err := editFn(ctx, chatID, msgID, content, contextUsage); err != nil {
+	if payload == nil {
+		payload = map[string]any{
+			PayloadKeyContent: content,
+		}
+	}
+	if _, ok := payload[PayloadKeyContent]; !ok {
+		payload[PayloadKeyContent] = content
+	}
+	if err := editFn(ctx, chatID, msgID, payload, contextUsage); err != nil {
 		c.RecordToolFeedbackMessage(chatID, msgID, baseContent)
 		return nil, false
 	}
@@ -437,7 +458,20 @@ func (c *PicoChannel) FinalizeToolFeedbackMessage(ctx context.Context, msg bus.O
 	if !outboundMessageFinalizesTrackedToolFeedback(msg) {
 		return nil, false
 	}
-	return c.finalizeTrackedToolFeedbackMessage(ctx, msg.ChatID, msg.Content, c.editMessage, msg.ContextUsage)
+	payload := map[string]any{
+		PayloadKeyContent: msg.Content,
+	}
+	if modelName := strings.TrimSpace(msg.Context.Raw[PayloadKeyModelName]); modelName != "" {
+		payload[PayloadKeyModelName] = modelName
+	}
+	return c.finalizeTrackedToolFeedbackMessage(
+		ctx,
+		msg.ChatID,
+		msg.Content,
+		c.editMessagePayload,
+		payload,
+		msg.ContextUsage,
+	)
 }
 
 // StartTyping implements channels.TypingCapable.
@@ -496,6 +530,7 @@ func (c *PicoChannel) BeginStream(ctx context.Context, chatID string) (channels.
 type picoStreamer struct {
 	channel          *PicoChannel
 	chatID           string
+	modelName        string
 	messageID        string
 	reasoningID      string
 	throttleInterval time.Duration
@@ -509,6 +544,15 @@ type picoStreamer struct {
 	mu               sync.Mutex
 }
 
+func (s *picoStreamer) SetModelName(modelName string) {
+	if s == nil {
+		return
+	}
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	s.modelName = strings.TrimSpace(modelName)
+}
+
 func (s *picoStreamer) Update(ctx context.Context, content string) error {
 	s.mu.Lock()
 	defer s.mu.Unlock()
@@ -613,13 +657,23 @@ func (s *picoStreamer) sendLocked(ctx context.Context, content string, contextUs
 			PayloadKeyContent: content,
 			"message_id":      s.messageID,
 		}
+		if s.modelName != "" {
+			payload[PayloadKeyModelName] = s.modelName
+		}
 		setContextUsagePayload(payload, contextUsage)
 		outMsg := newMessage(TypeMessageCreate, payload)
 		if err := s.channel.broadcastToSession(s.chatID, outMsg); err != nil {
 			return err
 		}
 	} else if content != s.lastContent || contextUsage != nil {
-		if err := s.channel.editMessage(ctx, s.chatID, s.messageID, content, contextUsage); err != nil {
+		payload := map[string]any{
+			PayloadKeyContent: content,
+			"message_id":      s.messageID,
+		}
+		if s.modelName != "" {
+			payload[PayloadKeyModelName] = s.modelName
+		}
+		if err := s.channel.editMessagePayload(ctx, s.chatID, s.messageID, payload, contextUsage); err != nil {
 			return err
 		}
 	}
@@ -642,6 +696,9 @@ func (s *picoStreamer) sendReasoningLocked(ctx context.Context, content string)
 			PayloadKeyKind:    MessageKindThought,
 			PayloadKeyThought: true,
 		}
+		if s.modelName != "" {
+			payload[PayloadKeyModelName] = s.modelName
+		}
 		outMsg := newMessage(TypeMessageCreate, payload)
 		if err := s.channel.broadcastToSession(s.chatID, outMsg); err != nil {
 			return err
@@ -653,6 +710,9 @@ func (s *picoStreamer) sendReasoningLocked(ctx context.Context, content string)
 			PayloadKeyKind:    MessageKindThought,
 			PayloadKeyThought: true,
 		}
+		if s.modelName != "" {
+			payload[PayloadKeyModelName] = s.modelName
+		}
 		outMsg := newMessage(TypeMessageUpdate, payload)
 		if err := s.channel.broadcastToSession(s.chatID, outMsg); err != nil {
 			return err
@@ -744,6 +804,9 @@ func (c *PicoChannel) SendMedia(ctx context.Context, msg bus.OutboundMediaMessag
 		"attachments":     attachments,
 		"message_id":      msgID,
 	})
+	if modelName := strings.TrimSpace(msg.Context.Raw[PayloadKeyModelName]); modelName != "" {
+		outMsg.Payload[PayloadKeyModelName] = modelName
+	}
 
 	if err := c.broadcastToSession(msg.ChatID, outMsg); err != nil {
 		return nil, err
@@ -1358,11 +1421,30 @@ func (c *PicoChannel) editMessage(
 	content string,
 	contextUsage *bus.ContextUsage,
 ) error {
-	payload := map[string]any{
-		"message_id": messageID,
-		"content":    content,
+	return c.editMessagePayload(ctx, chatID, messageID, map[string]any{
+		PayloadKeyContent: content,
+	}, contextUsage)
+}
+
+func (c *PicoChannel) editMessagePayload(
+	ctx context.Context,
+	chatID string,
+	messageID string,
+	payload map[string]any,
+	contextUsage *bus.ContextUsage,
+) error {
+	if payload == nil {
+		payload = map[string]any{}
 	}
-	setContextUsagePayload(payload, contextUsage)
-	outMsg := newMessage(TypeMessageUpdate, payload)
+	normalized := make(map[string]any, len(payload)+1)
+	for key, value := range payload {
+		normalized[key] = value
+	}
+	if _, ok := normalized[PayloadKeyContent]; !ok {
+		normalized[PayloadKeyContent] = ""
+	}
+	normalized["message_id"] = messageID
+	setContextUsagePayload(normalized, contextUsage)
+	outMsg := newMessage(TypeMessageUpdate, normalized)
 	return c.broadcastToSession(chatID, outMsg)
 }

pkg/channels/pico/pico_test.go

@@ -46,12 +46,15 @@ func TestFinalizeTrackedToolFeedbackMessage_StopsTrackingBeforeEdit(t *testing.T
 		context.Background(),
 		"pico:chat-1",
 		"final reply",
-		func(_ context.Context, chatID, messageID, content string, contextUsage *bus.ContextUsage) error {
+		func(_ context.Context, chatID, messageID string, payload map[string]any, contextUsage *bus.ContextUsage) error {
 			if _, ok := ch.currentToolFeedbackMessage(chatID); ok {
 				t.Fatal("expected tracked tool feedback to be stopped before edit")
 			}
-			if chatID != "pico:chat-1" || messageID != "msg-1" || content != "final reply" {
-				t.Fatalf("unexpected edit args: %s %s %s", chatID, messageID, content)
+			if chatID != "pico:chat-1" || messageID != "msg-1" {
+				t.Fatalf("unexpected edit args: %s %s", chatID, messageID)
+			}
+			if got := payload[PayloadKeyContent]; got != "final reply" {
+				t.Fatalf("unexpected content payload: %#v", got)
 			}
 			if contextUsage != nil {
 				t.Fatalf("unexpected context usage: %+v", contextUsage)
@@ -59,6 +62,7 @@ func TestFinalizeTrackedToolFeedbackMessage_StopsTrackingBeforeEdit(t *testing.T
 			return nil
 		},
 		nil,
+		nil,
 	)
 	if !handled {
 		t.Fatal("expected finalizeTrackedToolFeedbackMessage to handle tracked message")
@@ -115,7 +119,8 @@ func TestSend_ThoughtMessageDoesNotFinalizeTrackedToolFeedback(t *testing.T) {
 			Channel: "pico",
 			ChatID:  "pico:sess-1",
 			Raw: map[string]string{
-				"message_kind": MessageKindThought,
+				"message_kind":      MessageKindThought,
+				PayloadKeyModelName: "gpt-5.4-mini",
 			},
 		},
 	}); err != nil {
@@ -134,6 +139,9 @@ func TestSend_ThoughtMessageDoesNotFinalizeTrackedToolFeedback(t *testing.T) {
 		if got := payload[PayloadKeyKind]; got != MessageKindThought {
 			t.Fatalf("thought kind = %#v, want %q", got, MessageKindThought)
 		}
+		if got := payload[PayloadKeyModelName]; got != "gpt-5.4-mini" {
+			t.Fatalf("thought model_name = %#v, want %q", got, "gpt-5.4-mini")
+		}
 		if got := payload["message_id"]; got == "msg-progress" || got == nil || got == "" {
 			t.Fatalf("thought message_id = %#v, want new non-progress id", got)
 		}
@@ -151,6 +159,9 @@ func TestSend_ThoughtMessageDoesNotFinalizeTrackedToolFeedback(t *testing.T) {
 		Context: bus.InboundContext{
 			Channel: "pico",
 			ChatID:  "pico:sess-1",
+			Raw: map[string]string{
+				PayloadKeyModelName: "gpt-5.4",
+			},
 		},
 		ContextUsage: &bus.ContextUsage{
 			UsedTokens:       321,
@@ -174,6 +185,9 @@ func TestSend_ThoughtMessageDoesNotFinalizeTrackedToolFeedback(t *testing.T) {
 		if got := payload[PayloadKeyContent]; got != "final reply" {
 			t.Fatalf("final content = %#v, want %q", got, "final reply")
 		}
+		if got := payload[PayloadKeyModelName]; got != "gpt-5.4" {
+			t.Fatalf("final model_name = %#v, want %q", got, "gpt-5.4")
+		}
 		rawUsage, ok := payload["context_usage"].(map[string]any)
 		if !ok {
 			t.Fatalf("final context_usage = %#v, want map payload", payload["context_usage"])
@@ -193,6 +207,54 @@ func TestSend_ThoughtMessageDoesNotFinalizeTrackedToolFeedback(t *testing.T) {
 	}
 }
 
+func TestSend_ToolCallsMessageIncludesModelName(t *testing.T) {
+	ch := newTestPicoChannel(t)
+
+	if err := ch.Start(context.Background()); err != nil {
+		t.Fatalf("Start() error = %v", err)
+	}
+	defer ch.Stop(context.Background())
+
+	clientConn, received, cleanup := newTestPicoWebSocket(t)
+	defer cleanup()
+	ch.addConnForTest(&picoConn{id: "conn-1", conn: clientConn, sessionID: "sess-1"})
+
+	if _, err := ch.Send(context.Background(), bus.OutboundMessage{
+		ChatID:  "pico:sess-1",
+		Content: "",
+		Context: bus.InboundContext{
+			Channel: "pico",
+			ChatID:  "pico:sess-1",
+			Raw: map[string]string{
+				"message_kind":      MessageKindToolCalls,
+				PayloadKeyModelName: "gpt-5.4",
+				PayloadKeyToolCalls: `[{"id":"call_1","type":"function","function":{"name":"read_file","arguments":"{\"path\":\"README.md\"}"}}]`,
+			},
+		},
+	}); err != nil {
+		t.Fatalf("Send(tool_calls) error = %v", err)
+	}
+
+	select {
+	case msg := <-received:
+		if msg.Type != TypeMessageCreate {
+			t.Fatalf("tool_calls message type = %q, want %q", msg.Type, TypeMessageCreate)
+		}
+		payload := msg.Payload
+		if got := payload[PayloadKeyKind]; got != MessageKindToolCalls {
+			t.Fatalf("tool_calls kind = %#v, want %q", got, MessageKindToolCalls)
+		}
+		if got := payload[PayloadKeyModelName]; got != "gpt-5.4" {
+			t.Fatalf("tool_calls model_name = %#v, want %q", got, "gpt-5.4")
+		}
+		if _, ok := payload[PayloadKeyToolCalls].([]any); !ok {
+			t.Fatalf("tool_calls payload = %#v, want parsed array", payload[PayloadKeyToolCalls])
+		}
+	case <-time.After(time.Second):
+		t.Fatal("expected tool_calls message to be delivered")
+	}
+}
+
 func TestSendPlaceholder_EmitsNormalMessageWithoutKind(t *testing.T) {
 	ch := newTestPicoChannel(t)
 	ch.bc.Placeholder.Enabled = true
@@ -257,6 +319,9 @@ func TestBeginStream_CreatesAndUpdatesSameMessage(t *testing.T) {
 	if err != nil {
 		t.Fatalf("BeginStream() error = %v", err)
 	}
+	if setter, ok := streamer.(interface{ SetModelName(modelName string) }); ok {
+		setter.SetModelName("gpt-5.4")
+	}
 	if err := streamer.Update(context.Background(), "hello"); err != nil {
 		t.Fatalf("Update(first) error = %v", err)
 	}
@@ -271,6 +336,9 @@ func TestBeginStream_CreatesAndUpdatesSameMessage(t *testing.T) {
 	if got := first.Payload[PayloadKeyContent]; got != "hello" {
 		t.Fatalf("first content = %#v, want hello", got)
 	}
+	if got := first.Payload[PayloadKeyModelName]; got != "gpt-5.4" {
+		t.Fatalf("first model_name = %#v, want %q", got, "gpt-5.4")
+	}
 
 	rawStreamer := streamer.(*picoStreamer)
 	rawStreamer.mu.Lock()
@@ -290,6 +358,9 @@ func TestBeginStream_CreatesAndUpdatesSameMessage(t *testing.T) {
 	if got := second.Payload[PayloadKeyContent]; got != secondContent {
 		t.Fatalf("second content = %#v, want %q", got, secondContent)
 	}
+	if got := second.Payload[PayloadKeyModelName]; got != "gpt-5.4" {
+		t.Fatalf("second model_name = %#v, want %q", got, "gpt-5.4")
+	}
 }
 
 func TestBeginStream_DefaultStreamingShowsSmallIncrements(t *testing.T) {
@@ -355,6 +426,9 @@ func TestBeginStream_StreamsReasoningAsThoughtUpdates(t *testing.T) {
 	if !ok {
 		t.Fatal("pico stream should support reasoning updates")
 	}
+	if setter, ok := streamer.(interface{ SetModelName(modelName string) }); ok {
+		setter.SetModelName("gpt-5.4-mini")
+	}
 	if err := reasoningStreamer.UpdateReasoning(context.Background(), "thinking"); err != nil {
 		t.Fatalf("UpdateReasoning(first) error = %v", err)
 	}
@@ -372,6 +446,9 @@ func TestBeginStream_StreamsReasoningAsThoughtUpdates(t *testing.T) {
 	if got := first.Payload[PayloadKeyContent]; got != "thinking" {
 		t.Fatalf("first content = %#v, want thinking", got)
 	}
+	if got := first.Payload[PayloadKeyModelName]; got != "gpt-5.4-mini" {
+		t.Fatalf("first model_name = %#v, want %q", got, "gpt-5.4-mini")
+	}
 
 	if err := reasoningStreamer.UpdateReasoning(context.Background(), "thinking more"); err != nil {
 		t.Fatalf("UpdateReasoning(second) error = %v", err)
@@ -389,6 +466,9 @@ func TestBeginStream_StreamsReasoningAsThoughtUpdates(t *testing.T) {
 	if got := second.Payload[PayloadKeyContent]; got != "thinking more" {
 		t.Fatalf("second content = %#v, want thinking more", got)
 	}
+	if got := second.Payload[PayloadKeyModelName]; got != "gpt-5.4-mini" {
+		t.Fatalf("second model_name = %#v, want %q", got, "gpt-5.4-mini")
+	}
 }
 
 func TestBeginStream_ThrottlesIntermediateUpdatesAndFinalFlushes(t *testing.T) {
@@ -473,6 +553,9 @@ func TestBeginStream_FinalizeIncludesContextUsage(t *testing.T) {
 	if err != nil {
 		t.Fatalf("BeginStream() error = %v", err)
 	}
+	if setter, ok := streamer.(interface{ SetModelName(modelName string) }); ok {
+		setter.SetModelName("gpt-5.4")
+	}
 	if err := streamer.Update(context.Background(), "partial"); err != nil {
 		t.Fatalf("Update() error = %v", err)
 	}
@@ -501,6 +584,9 @@ func TestBeginStream_FinalizeIncludesContextUsage(t *testing.T) {
 	if got := final.Payload["message_id"]; got != msgID {
 		t.Fatalf("final message_id = %#v, want %q", got, msgID)
 	}
+	if got := final.Payload[PayloadKeyModelName]; got != "gpt-5.4" {
+		t.Fatalf("final model_name = %#v, want %q", got, "gpt-5.4")
+	}
 	rawUsage, ok := final.Payload["context_usage"].(map[string]any)
 	if !ok {
 		t.Fatalf("final context_usage = %#v, want map", final.Payload["context_usage"])

pkg/channels/pico/protocol.go

@@ -27,6 +27,7 @@ const (
 	PayloadKeyKind        = "kind"
 	PayloadKeyPlaceholder = "placeholder"
 	PayloadKeyToolCalls   = "tool_calls"
+	PayloadKeyModelName   = "model_name"
 
 	MessageKindThought   = "thought"
 	MessageKindToolCalls = "tool_calls"

pkg/memory/jsonl_test.go

@@ -130,6 +130,32 @@ func TestAddFullMessage_WithToolCalls(t *testing.T) {
 	}
 }
 
+func TestAddFullMessage_PreservesModelName(t *testing.T) {
+	store := newTestStore(t)
+	ctx := context.Background()
+
+	msg := providers.Message{
+		Role:      "assistant",
+		Content:   "done",
+		ModelName: "gpt-5.4-mini",
+	}
+
+	if err := store.AddFullMessage(ctx, "model-name", msg); err != nil {
+		t.Fatalf("AddFullMessage: %v", err)
+	}
+
+	history, err := store.GetHistory(ctx, "model-name")
+	if err != nil {
+		t.Fatalf("GetHistory: %v", err)
+	}
+	if len(history) != 1 {
+		t.Fatalf("expected 1, got %d", len(history))
+	}
+	if history[0].ModelName != "gpt-5.4-mini" {
+		t.Fatalf("ModelName = %q, want %q", history[0].ModelName, "gpt-5.4-mini")
+	}
+}
+
 func TestAddFullMessage_ToolCallID(t *testing.T) {
 	store := newTestStore(t)
 	ctx := context.Background()

pkg/providers/fallback.go

@@ -17,6 +17,7 @@ type FallbackChain struct {
 type FallbackCandidate struct {
 	Provider    string
 	Model       string
+	DisplayName string // optional configured alias/raw model label for persistence/UI
 	RPM         int    // requests per minute; 0 means unrestricted
 	IdentityKey string // optional stable config identity for cooldown/rate limiting
 }
@@ -32,10 +33,11 @@ func (c FallbackCandidate) StableKey() string {
 
 // FallbackResult contains the successful response and metadata about all attempts.
 type FallbackResult struct {
-	Response *LLMResponse
-	Provider string
-	Model    string
-	Attempts []FallbackAttempt
+	Response    *LLMResponse
+	Provider    string
+	Model       string
+	IdentityKey string
+	Attempts    []FallbackAttempt
 }
 
 // FallbackAttempt records one attempt in the fallback chain.
@@ -85,8 +87,9 @@ func ResolveCandidatesWithLookup(
 		}
 		seen[key] = true
 		candidates = append(candidates, FallbackCandidate{
-			Provider: ref.Provider,
-			Model:    ref.Model,
+			Provider:    ref.Provider,
+			Model:       ref.Model,
+			DisplayName: candidateRaw,
 		})
 	}
 
@@ -187,6 +190,7 @@ func (fc *FallbackChain) Execute(
 			result.Response = resp
 			result.Provider = candidate.Provider
 			result.Model = candidate.Model
+			result.IdentityKey = candidate.StableKey()
 			return result, nil
 		}
 
@@ -305,6 +309,7 @@ func (fc *FallbackChain) ExecuteImage(
 			result.Response = resp
 			result.Provider = candidate.Provider
 			result.Model = candidate.Model
+			result.IdentityKey = candidate.StableKey()
 			return result, nil
 		}
 

pkg/providers/protocoltypes/types.go

@@ -86,6 +86,7 @@ type Attachment struct {
 type Message struct {
 	Role             string         `json:"role"`
 	Content          string         `json:"content"`
+	ModelName        string         `json:"model_name,omitempty"`
 	Media            []string       `json:"media,omitempty"`
 	Attachments      []Attachment   `json:"attachments,omitempty"`
 	ReasoningContent string         `json:"reasoning_content,omitempty"`

pkg/seahorse/schema.go

@@ -46,6 +46,7 @@ func runSchema(db *sql.DB) error {
 			conversation_id INTEGER NOT NULL REFERENCES conversations(conversation_id),
 			role            TEXT NOT NULL,
 			content         TEXT NOT NULL DEFAULT '',
+			model_name      TEXT NOT NULL DEFAULT '',
 			reasoning_content TEXT NOT NULL DEFAULT '',
 			token_count     INTEGER NOT NULL DEFAULT 0,
 			created_at      TEXT NOT NULL DEFAULT (datetime('now'))
@@ -162,6 +163,9 @@ func runSchema(db *sql.DB) error {
 	if err := ensureMessagesReasoningContentColumn(db); err != nil {
 		return err
 	}
+	if err := ensureMessagesModelNameColumn(db); err != nil {
+		return err
+	}
 	return nil
 }
 
@@ -180,6 +184,21 @@ func ensureMessagesReasoningContentColumn(db *sql.DB) error {
 	return nil
 }
 
+func ensureMessagesModelNameColumn(db *sql.DB) error {
+	hasColumn, err := tableHasColumn(db, "messages", "model_name")
+	if err != nil {
+		return fmt.Errorf("check messages.model_name: %w", err)
+	}
+	if hasColumn {
+		return nil
+	}
+
+	if _, err := db.Exec(`ALTER TABLE messages ADD COLUMN model_name TEXT NOT NULL DEFAULT ''`); err != nil {
+		return fmt.Errorf("add messages.model_name: %w", err)
+	}
+	return nil
+}
+
 func tableHasColumn(db *sql.DB, tableName, columnName string) (bool, error) {
 	rows, err := db.Query(fmt.Sprintf(`PRAGMA table_info(%s)`, tableName))
 	if err != nil {

pkg/seahorse/schema_test.go

@@ -138,6 +138,37 @@ func TestRunSchemaAddsMessagesReasoningContentColumn(t *testing.T) {
 	}
 }
 
+func TestRunSchemaAddsMessagesModelNameColumn(t *testing.T) {
+	db := openTestDB(t)
+
+	_, err := db.Exec(`CREATE TABLE messages (
+		message_id INTEGER PRIMARY KEY AUTOINCREMENT,
+		conversation_id INTEGER NOT NULL,
+		role TEXT NOT NULL,
+		content TEXT NOT NULL DEFAULT '',
+		reasoning_content TEXT NOT NULL DEFAULT '',
+		token_count INTEGER NOT NULL DEFAULT 0,
+		created_at TEXT NOT NULL DEFAULT (datetime('now'))
+	)`)
+	if err != nil {
+		t.Fatalf("create legacy messages table: %v", err)
+	}
+
+	err = runSchema(db)
+	if err != nil {
+		t.Fatalf("runSchema: %v", err)
+	}
+
+	var count int
+	err = db.QueryRow(`SELECT count(*) FROM pragma_table_info('messages') WHERE name = 'model_name'`).Scan(&count)
+	if err != nil {
+		t.Fatalf("query pragma_table_info: %v", err)
+	}
+	if count != 1 {
+		t.Fatalf("model_name column count = %d, want 1", count)
+	}
+}
+
 func TestMigrationConversationUnique(t *testing.T) {
 	db := openTestDB(t)
 	if err := runSchema(db); err != nil {

pkg/seahorse/short_engine.go

@@ -258,6 +258,7 @@ func (e *Engine) Ingest(ctx context.Context, sessionKey string, messages []Messa
 				conv.ConversationID,
 				msg.Role,
 				msg.Parts,
+				msg.ModelName,
 				msg.ReasoningContent,
 				msg.TokenCount,
 			)
@@ -267,6 +268,7 @@ func (e *Engine) Ingest(ctx context.Context, sessionKey string, messages []Messa
 				conv.ConversationID,
 				msg.Role,
 				msg.Content,
+				msg.ModelName,
 				msg.ReasoningContent,
 				msg.TokenCount,
 			)
@@ -431,6 +433,31 @@ func (e *Engine) Bootstrap(ctx context.Context, sessionKey string, messages []Me
 		return fmt.Errorf("bootstrap: get messages: %w", err)
 	}
 
+	// Migration repair path: old SeaHorse rows may be missing reasoning_content
+	// even though the canonical JSONL history already has it. Backfill those
+	// rows in place so we do not treat this as edited history and leave stale
+	// summaries/context behind after a partial raw-message rebuild.
+	repairedReasoning, err := e.repairBootstrapReasoningContent(ctx, dbMsgs, messages)
+	if err != nil {
+		return fmt.Errorf("bootstrap: repair reasoning_content: %w", err)
+	}
+	repairedModelName, err := e.repairBootstrapModelName(ctx, dbMsgs, messages)
+	if err != nil {
+		return fmt.Errorf("bootstrap: repair model_name: %w", err)
+	}
+	if (repairedReasoning || repairedModelName) && len(dbMsgs) == len(messages) {
+		matched := true
+		for i := range messages {
+			if !messageMatches(dbMsgs[i], messages[i]) {
+				matched = false
+				break
+			}
+		}
+		if matched {
+			return nil
+		}
+	}
+
 	// Fast path: DB has same count and exact match → no-op
 	if len(dbMsgs) == len(messages) {
 		matched := true
@@ -445,16 +472,6 @@ func (e *Engine) Bootstrap(ctx context.Context, sessionKey string, messages []Me
 		}
 	}
 
-	// Migration repair path: old SeaHorse rows may be missing reasoning_content
-	// even though the canonical JSONL history already has it. Backfill those
-	// rows in place so we do not treat this as edited history and leave stale
-	// summaries/context behind after a partial raw-message rebuild.
-	if repaired, err := e.repairBootstrapReasoningContent(ctx, dbMsgs, messages); err != nil {
-		return fmt.Errorf("bootstrap: repair reasoning_content: %w", err)
-	} else if repaired && len(dbMsgs) == len(messages) {
-		return nil
-	}
-
 	// Find longest matching prefix from the start
 	anchor := -1
 	compareLen := min(len(dbMsgs), len(messages))
@@ -465,14 +482,16 @@ func (e *Engine) Bootstrap(ctx context.Context, sessionKey string, messages []Me
 		} else {
 			// Mismatch detected - log details and rebuild
 			logger.InfoCF("seahorse", "bootstrap: mismatch detected", map[string]any{
-				"conv_id":     conv.ConversationID,
-				"index":       i,
-				"db_role":     dbMsgs[i].Role,
-				"db_content":  truncate(dbMsgs[i].Content, 50),
-				"db_parts":    len(dbMsgs[i].Parts),
-				"msg_role":    messages[i].Role,
-				"msg_content": truncate(messages[i].Content, 50),
-				"msg_parts":   len(messages[i].Parts),
+				"conv_id":        conv.ConversationID,
+				"index":          i,
+				"db_role":        dbMsgs[i].Role,
+				"db_content":     truncate(dbMsgs[i].Content, 50),
+				"db_parts":       len(dbMsgs[i].Parts),
+				"db_model_name":  dbMsgs[i].ModelName,
+				"msg_role":       messages[i].Role,
+				"msg_content":    truncate(messages[i].Content, 50),
+				"msg_parts":      len(messages[i].Parts),
+				"msg_model_name": messages[i].ModelName,
 			})
 			break
 		}
@@ -559,7 +578,7 @@ func (e *Engine) repairBootstrapReasoningContent(ctx context.Context, dbMsgs, me
 	}
 
 	for i := range overlap {
-		if !messageMatchesIgnoringReasoning(dbMsgs[i], messages[i]) {
+		if !messageMatchesIgnoringReasoningAndModelName(dbMsgs[i], messages[i]) {
 			return false, nil
 		}
 		if dbMsgs[i].ReasoningContent == messages[i].ReasoningContent {
@@ -596,6 +615,57 @@ func (e *Engine) repairBootstrapReasoningContent(ctx context.Context, dbMsgs, me
 	return true, nil
 }
 
+func (e *Engine) repairBootstrapModelName(ctx context.Context, dbMsgs, messages []Message) (bool, error) {
+	if len(dbMsgs) == 0 || len(messages) == 0 {
+		return false, nil
+	}
+
+	overlap := min(len(messages), len(dbMsgs))
+
+	var updates []struct {
+		index     int
+		messageID int64
+		modelName string
+	}
+
+	for i := range overlap {
+		if !messageMatchesIgnoringReasoningAndModelName(dbMsgs[i], messages[i]) {
+			return false, nil
+		}
+		if dbMsgs[i].ModelName == messages[i].ModelName {
+			continue
+		}
+		if messages[i].ModelName == "" {
+			return false, nil
+		}
+		updates = append(updates, struct {
+			index     int
+			messageID int64
+			modelName string
+		}{
+			index:     i,
+			messageID: dbMsgs[i].ID,
+			modelName: messages[i].ModelName,
+		})
+	}
+
+	if len(updates) == 0 {
+		return false, nil
+	}
+
+	for _, update := range updates {
+		if err := e.store.UpdateMessageModelName(ctx, update.messageID, update.modelName); err != nil {
+			return false, err
+		}
+		dbMsgs[update.index].ModelName = update.modelName
+	}
+
+	logger.InfoCF("seahorse", "bootstrap: repaired missing model_name", map[string]any{
+		"messages": len(updates),
+	})
+	return true, nil
+}
+
 // truncate shortens a string for logging.
 func truncate(s string, maxLen int) string {
 	if len(s) <= maxLen {
@@ -610,13 +680,20 @@ func truncate(s string, maxLen int) string {
 // For messages with Parts (tool_use, tool_result), compare Parts instead of Content
 // because structured messages are matched by their parts payload.
 func messageMatches(a, b Message) bool {
-	if a.Role != b.Role || a.ReasoningContent != b.ReasoningContent {
+	if a.Role != b.Role || a.ReasoningContent != b.ReasoningContent || a.ModelName != b.ModelName {
 		return false
 	}
 	return messageMatchesIgnoringReasoning(a, b)
 }
 
 func messageMatchesIgnoringReasoning(a, b Message) bool {
+	if a.ModelName != b.ModelName {
+		return false
+	}
+	return messageMatchesIgnoringReasoningAndModelName(a, b)
+}
+
+func messageMatchesIgnoringReasoningAndModelName(a, b Message) bool {
 	if a.Role != b.Role {
 		return false
 	}

pkg/seahorse/short_engine_test.go

@@ -25,6 +25,43 @@ func newTestEngine(t *testing.T) *Engine {
 	}
 }
 
+func prepareBootstrapRepairConversation(
+	t *testing.T,
+	eng *Engine,
+	ctx context.Context,
+	sessionKey string,
+) (*Conversation, []Message) {
+	t.Helper()
+
+	conv, err := eng.store.GetOrCreateConversation(ctx, sessionKey)
+	if err != nil {
+		t.Fatalf("GetOrCreateConversation: %v", err)
+	}
+
+	userMsg, err := eng.store.AddMessage(ctx, conv.ConversationID, "user", "hello", 3)
+	if err != nil {
+		t.Fatalf("AddMessage user: %v", err)
+	}
+
+	assistantMsg, err := eng.store.AddMessage(ctx, conv.ConversationID, "assistant", "world", 3)
+	if err != nil {
+		t.Fatalf("AddMessage assistant: %v", err)
+	}
+
+	if err := eng.store.AppendContextMessages(
+		ctx,
+		conv.ConversationID,
+		[]int64{userMsg.ID, assistantMsg.ID},
+	); err != nil {
+		t.Fatalf("AppendContextMessages: %v", err)
+	}
+
+	return conv, []Message{
+		{Role: "user", Content: "hello", TokenCount: 3},
+		{Role: "assistant", Content: "world", TokenCount: 3},
+	}
+}
+
 // --- compileSessionPattern ---
 
 func TestCompileSessionPattern(t *testing.T) {
@@ -328,6 +365,7 @@ func TestEngineIngestPreservesReasoningContent(t *testing.T) {
 		{
 			Role:             "assistant",
 			Content:          "world",
+			ModelName:        "gpt-5.4-mini",
 			ReasoningContent: "let me think this through",
 			TokenCount:       4,
 		},
@@ -353,6 +391,9 @@ func TestEngineIngestPreservesReasoningContent(t *testing.T) {
 			"let me think this through",
 		)
 	}
+	if stored[0].ModelName != "gpt-5.4-mini" {
+		t.Errorf("stored[0].ModelName = %q, want %q", stored[0].ModelName, "gpt-5.4-mini")
+	}
 
 	result, err := eng.Assemble(ctx, "agent:reasoning", AssembleInput{Budget: 1000})
 	if err != nil {
@@ -368,6 +409,140 @@ func TestEngineIngestPreservesReasoningContent(t *testing.T) {
 			"let me think this through",
 		)
 	}
+	if result.Messages[0].ModelName != "gpt-5.4-mini" {
+		t.Errorf("assembled model_name = %q, want %q", result.Messages[0].ModelName, "gpt-5.4-mini")
+	}
+}
+
+func TestBootstrapRepairsMissingModelName(t *testing.T) {
+	eng := newTestEngine(t)
+	ctx := context.Background()
+	sessionKey := "agent:repair-model-name"
+	conv, msgs := prepareBootstrapRepairConversation(t, eng, ctx, sessionKey)
+	msgs[1].ModelName = "gpt-5.4"
+
+	err := eng.Bootstrap(ctx, sessionKey, msgs)
+	if err != nil {
+		t.Fatalf("Bootstrap: %v", err)
+	}
+
+	stored, err := eng.store.GetMessages(ctx, conv.ConversationID, 10, 0)
+	if err != nil {
+		t.Fatalf("GetMessages: %v", err)
+	}
+	if len(stored) != 2 {
+		t.Fatalf("stored messages = %d, want 2", len(stored))
+	}
+	if stored[1].ModelName != "gpt-5.4" {
+		t.Fatalf("stored[1].ModelName = %q, want %q", stored[1].ModelName, "gpt-5.4")
+	}
+}
+
+func TestBootstrapRepairsReasoningContentAndModelNameTogether(t *testing.T) {
+	eng := newTestEngine(t)
+	ctx := context.Background()
+	sessionKey := "agent:repair-both-fields"
+
+	conv, err := eng.store.GetOrCreateConversation(ctx, sessionKey)
+	if err != nil {
+		t.Fatalf("GetOrCreateConversation: %v", err)
+	}
+
+	userMsg, err := eng.store.AddMessage(ctx, conv.ConversationID, "user", "hello", 3)
+	if err != nil {
+		t.Fatalf("AddMessage user: %v", err)
+	}
+
+	assistantMsg, err := eng.store.AddMessage(ctx, conv.ConversationID, "assistant", "world", 3)
+	if err != nil {
+		t.Fatalf("AddMessage assistant: %v", err)
+	}
+
+	err = eng.store.AppendContextMessages(ctx, conv.ConversationID, []int64{userMsg.ID, assistantMsg.ID})
+	if err != nil {
+		t.Fatalf("AppendContextMessages: %v", err)
+	}
+
+	err = eng.Bootstrap(ctx, sessionKey, []Message{
+		{Role: "user", Content: "hello", TokenCount: 3},
+		{
+			Role:             "assistant",
+			Content:          "world",
+			ModelName:        "gpt-5.4",
+			ReasoningContent: "let me think this through",
+			TokenCount:       3,
+		},
+	})
+	if err != nil {
+		t.Fatalf("Bootstrap: %v", err)
+	}
+
+	stored, err := eng.store.GetMessages(ctx, conv.ConversationID, 10, 0)
+	if err != nil {
+		t.Fatalf("GetMessages: %v", err)
+	}
+	if len(stored) != 2 {
+		t.Fatalf("stored messages = %d, want 2", len(stored))
+	}
+	if stored[1].ReasoningContent != "let me think this through" {
+		t.Fatalf("stored[1].ReasoningContent = %q, want %q", stored[1].ReasoningContent, "let me think this through")
+	}
+	if stored[1].ModelName != "gpt-5.4" {
+		t.Fatalf("stored[1].ModelName = %q, want %q", stored[1].ModelName, "gpt-5.4")
+	}
+}
+
+func TestBootstrapRepairsIncorrectNonEmptyModelName(t *testing.T) {
+	eng := newTestEngine(t)
+	ctx := context.Background()
+	sessionKey := "agent:repair-wrong-model-name"
+
+	conv, err := eng.store.GetOrCreateConversation(ctx, sessionKey)
+	if err != nil {
+		t.Fatalf("GetOrCreateConversation: %v", err)
+	}
+
+	userMsg, err := eng.store.AddMessage(ctx, conv.ConversationID, "user", "hello", 3)
+	if err != nil {
+		t.Fatalf("AddMessage user: %v", err)
+	}
+
+	assistantMsg, err := eng.store.AddMessageWithReasoning(
+		ctx,
+		conv.ConversationID,
+		"assistant",
+		"world",
+		"wrong-model",
+		"",
+		3,
+	)
+	if err != nil {
+		t.Fatalf("AddMessageWithReasoning assistant: %v", err)
+	}
+
+	err = eng.store.AppendContextMessages(ctx, conv.ConversationID, []int64{userMsg.ID, assistantMsg.ID})
+	if err != nil {
+		t.Fatalf("AppendContextMessages: %v", err)
+	}
+
+	err = eng.Bootstrap(ctx, sessionKey, []Message{
+		{Role: "user", Content: "hello", TokenCount: 3},
+		{Role: "assistant", Content: "world", ModelName: "gpt-5.4", TokenCount: 3},
+	})
+	if err != nil {
+		t.Fatalf("Bootstrap: %v", err)
+	}
+
+	stored, err := eng.store.GetMessages(ctx, conv.ConversationID, 10, 0)
+	if err != nil {
+		t.Fatalf("GetMessages: %v", err)
+	}
+	if len(stored) != 2 {
+		t.Fatalf("stored messages = %d, want 2", len(stored))
+	}
+	if stored[1].ModelName != "gpt-5.4" {
+		t.Fatalf("stored[1].ModelName = %q, want %q", stored[1].ModelName, "gpt-5.4")
+	}
 }
 
 func TestEngineIngestWithPartsPreservesReasoningContent(t *testing.T) {
@@ -620,35 +795,10 @@ func TestBootstrapRepairsMissingReasoningContent(t *testing.T) {
 	eng := newTestEngine(t)
 	ctx := context.Background()
 	sessionKey := "agent:repair-reasoning"
+	conv, msgs := prepareBootstrapRepairConversation(t, eng, ctx, sessionKey)
+	msgs[1].ReasoningContent = "let me think this through"
 
-	conv, err := eng.store.GetOrCreateConversation(ctx, sessionKey)
-	if err != nil {
-		t.Fatalf("GetOrCreateConversation: %v", err)
-	}
-
-	userMsg, err := eng.store.AddMessage(ctx, conv.ConversationID, "user", "hello", 3)
-	if err != nil {
-		t.Fatalf("AddMessage user: %v", err)
-	}
-
-	assistantMsg, err := eng.store.AddMessage(ctx, conv.ConversationID, "assistant", "world", 3)
-	if err != nil {
-		t.Fatalf("AddMessage assistant: %v", err)
-	}
-
-	err = eng.store.AppendContextMessages(
-		ctx,
-		conv.ConversationID,
-		[]int64{userMsg.ID, assistantMsg.ID},
-	)
-	if err != nil {
-		t.Fatalf("AppendContextMessages: %v", err)
-	}
-
-	err = eng.Bootstrap(ctx, sessionKey, []Message{
-		{Role: "user", Content: "hello", TokenCount: 3},
-		{Role: "assistant", Content: "world", ReasoningContent: "let me think this through", TokenCount: 3},
-	})
+	err := eng.Bootstrap(ctx, sessionKey, msgs)
 	if err != nil {
 		t.Fatalf("Bootstrap: %v", err)
 	}

pkg/seahorse/store.go

@@ -162,19 +162,25 @@ func (s *Store) getMessageTimeRange(ctx context.Context, convID int64) (time.Tim
 
 // AddMessage appends a message to a conversation.
 func (s *Store) AddMessage(ctx context.Context, convID int64, role, content string, tokenCount int) (*Message, error) {
-	return s.AddMessageWithReasoning(ctx, convID, role, content, "", tokenCount)
+	return s.AddMessageWithReasoning(ctx, convID, role, content, "", "", tokenCount)
 }
 
 // AddMessageWithReasoning appends a message with reasoning content to a conversation.
 func (s *Store) AddMessageWithReasoning(
 	ctx context.Context,
 	convID int64,
-	role, content, reasoningContent string,
+	role, content, modelName, reasoningContent string,
 	tokenCount int,
 ) (*Message, error) {
-	result, err := s.db.ExecContext(ctx,
-		"INSERT INTO messages (conversation_id, role, content, reasoning_content, token_count) VALUES (?, ?, ?, ?, ?)",
-		convID, role, content, reasoningContent, tokenCount,
+	result, err := s.db.ExecContext(
+		ctx,
+		"INSERT INTO messages (conversation_id, role, content, model_name, reasoning_content, token_count) VALUES (?, ?, ?, ?, ?, ?)",
+		convID,
+		role,
+		content,
+		modelName,
+		reasoningContent,
+		tokenCount,
 	)
 	if err != nil {
 		return nil, fmt.Errorf("add message: %w", err)
@@ -185,6 +191,7 @@ func (s *Store) AddMessageWithReasoning(
 		ConversationID:   convID,
 		Role:             role,
 		Content:          content,
+		ModelName:        modelName,
 		ReasoningContent: reasoningContent,
 		TokenCount:       tokenCount,
 	}, nil
@@ -224,7 +231,7 @@ func (s *Store) AddMessageWithParts(
 	parts []MessagePart,
 	tokenCount int,
 ) (*Message, error) {
-	return s.AddMessageWithPartsAndReasoning(ctx, convID, role, parts, "", tokenCount)
+	return s.AddMessageWithPartsAndReasoning(ctx, convID, role, parts, "", "", tokenCount)
 }
 
 // AddMessageWithPartsAndReasoning adds a message with structured parts and reasoning content.
@@ -233,6 +240,7 @@ func (s *Store) AddMessageWithPartsAndReasoning(
 	convID int64,
 	role string,
 	parts []MessagePart,
+	modelName string,
 	reasoningContent string,
 	tokenCount int,
 ) (*Message, error) {
@@ -245,9 +253,15 @@ func (s *Store) AddMessageWithPartsAndReasoning(
 	// Derive readable content from Parts for FTS5 indexing and summary formatting
 	readableContent := partsToReadableContent(parts)
 
-	result, err := tx.ExecContext(ctx,
-		"INSERT INTO messages (conversation_id, role, content, reasoning_content, token_count) VALUES (?, ?, ?, ?, ?)",
-		convID, role, readableContent, reasoningContent, tokenCount,
+	result, err := tx.ExecContext(
+		ctx,
+		"INSERT INTO messages (conversation_id, role, content, model_name, reasoning_content, token_count) VALUES (?, ?, ?, ?, ?, ?)",
+		convID,
+		role,
+		readableContent,
+		modelName,
+		reasoningContent,
+		tokenCount,
 	)
 	if err != nil {
 		return nil, fmt.Errorf("add message: %w", err)
@@ -282,6 +296,7 @@ func (s *Store) AddMessageWithPartsAndReasoning(
 		ID:               msgID,
 		ConversationID:   convID,
 		Role:             role,
+		ModelName:        modelName,
 		ReasoningContent: reasoningContent,
 		TokenCount:       tokenCount,
 		Parts:            make([]MessagePart, len(parts)),
@@ -295,7 +310,7 @@ func (s *Store) AddMessageWithPartsAndReasoning(
 
 // GetMessages retrieves messages for a conversation.
 func (s *Store) GetMessages(ctx context.Context, convID int64, limit int, beforeID int64) ([]Message, error) {
-	query := "SELECT message_id, conversation_id, role, content, reasoning_content, token_count, created_at FROM messages WHERE conversation_id = ?"
+	query := "SELECT message_id, conversation_id, role, content, model_name, reasoning_content, token_count, created_at FROM messages WHERE conversation_id = ?"
 	args := []any{convID}
 	if beforeID > 0 {
 		query += " AND message_id < ?"
@@ -322,6 +337,7 @@ func (s *Store) GetMessages(ctx context.Context, convID int64, limit int, before
 			&msg.ConversationID,
 			&msg.Role,
 			&msg.Content,
+			&msg.ModelName,
 			&msg.ReasoningContent,
 			&msg.TokenCount,
 			&createdAt,
@@ -362,9 +378,9 @@ func (s *Store) GetMessageByID(ctx context.Context, messageID int64) (*Message,
 	var createdAt string
 	err := s.db.QueryRowContext(
 		ctx,
-		"SELECT message_id, conversation_id, role, content, reasoning_content, token_count, created_at FROM messages WHERE message_id = ?",
+		"SELECT message_id, conversation_id, role, content, model_name, reasoning_content, token_count, created_at FROM messages WHERE message_id = ?",
 		messageID,
-	).Scan(&msg.ID, &msg.ConversationID, &msg.Role, &msg.Content, &msg.ReasoningContent, &msg.TokenCount, &createdAt)
+	).Scan(&msg.ID, &msg.ConversationID, &msg.Role, &msg.Content, &msg.ModelName, &msg.ReasoningContent, &msg.TokenCount, &createdAt)
 	if err == sql.ErrNoRows {
 		return nil, fmt.Errorf("message %d not found", messageID)
 	}
@@ -398,6 +414,27 @@ func (s *Store) UpdateMessageReasoningContent(ctx context.Context, messageID int
 	return nil
 }
 
+func (s *Store) UpdateMessageModelName(ctx context.Context, messageID int64, modelName string) error {
+	result, err := s.db.ExecContext(
+		ctx,
+		"UPDATE messages SET model_name = ? WHERE message_id = ?",
+		modelName,
+		messageID,
+	)
+	if err != nil {
+		return fmt.Errorf("update message model_name: %w", err)
+	}
+
+	rowsAffected, err := result.RowsAffected()
+	if err != nil {
+		return fmt.Errorf("update message model_name rows affected: %w", err)
+	}
+	if rowsAffected == 0 {
+		return fmt.Errorf("message %d not found", messageID)
+	}
+	return nil
+}
+
 func (s *Store) loadMessageParts(ctx context.Context, msgID int64) ([]MessagePart, error) {
 	rows, err := s.db.QueryContext(ctx,
 		`SELECT part_id, message_id, type, text, name, arguments, tool_call_id, media_uri, mime_type
@@ -581,8 +618,9 @@ func (s *Store) LinkSummaryToMessages(ctx context.Context, summaryID string, mes
 
 // GetSummarySourceMessages retrieves source messages for a summary.
 func (s *Store) GetSummarySourceMessages(ctx context.Context, summaryID string) ([]Message, error) {
-	rows, err := s.db.QueryContext(ctx,
-		`SELECT m.message_id, m.conversation_id, m.role, m.content, m.reasoning_content, m.token_count, m.created_at
+	rows, err := s.db.QueryContext(
+		ctx,
+		`SELECT m.message_id, m.conversation_id, m.role, m.content, m.model_name, m.reasoning_content, m.token_count, m.created_at
 		 FROM summary_messages sm
 		 JOIN messages m ON m.message_id = sm.message_id
 		 WHERE sm.summary_id = ?
@@ -603,6 +641,7 @@ func (s *Store) GetSummarySourceMessages(ctx context.Context, summaryID string)
 			&msg.ConversationID,
 			&msg.Role,
 			&msg.Content,
+			&msg.ModelName,
 			&msg.ReasoningContent,
 			&msg.TokenCount,
 			&createdAt,

pkg/seahorse/store_test.go

@@ -210,6 +210,7 @@ func TestStoreAddAndGetMessagesWithReasoningContent(t *testing.T) {
 		conv.ConversationID,
 		"assistant",
 		"hello world",
+		"gpt-5.4-mini",
 		"let me think",
 		5,
 	)
@@ -219,6 +220,9 @@ func TestStoreAddAndGetMessagesWithReasoningContent(t *testing.T) {
 	if msg.ReasoningContent != "let me think" {
 		t.Fatalf("ReasoningContent = %q, want %q", msg.ReasoningContent, "let me think")
 	}
+	if msg.ModelName != "gpt-5.4-mini" {
+		t.Fatalf("ModelName = %q, want %q", msg.ModelName, "gpt-5.4-mini")
+	}
 
 	msgs, err := s.GetMessages(ctx, conv.ConversationID, 10, 0)
 	if err != nil {
@@ -230,6 +234,9 @@ func TestStoreAddAndGetMessagesWithReasoningContent(t *testing.T) {
 	if msgs[0].ReasoningContent != "let me think" {
 		t.Errorf("ReasoningContent = %q, want %q", msgs[0].ReasoningContent, "let me think")
 	}
+	if msgs[0].ModelName != "gpt-5.4-mini" {
+		t.Errorf("ModelName = %q, want %q", msgs[0].ModelName, "gpt-5.4-mini")
+	}
 
 	found, err := s.GetMessageByID(ctx, msg.ID)
 	if err != nil {
@@ -238,6 +245,9 @@ func TestStoreAddAndGetMessagesWithReasoningContent(t *testing.T) {
 	if found.ReasoningContent != "let me think" {
 		t.Errorf("GetMessageByID ReasoningContent = %q, want %q", found.ReasoningContent, "let me think")
 	}
+	if found.ModelName != "gpt-5.4-mini" {
+		t.Errorf("GetMessageByID ModelName = %q, want %q", found.ModelName, "gpt-5.4-mini")
+	}
 }
 
 func TestStoreAddMessageWithParts(t *testing.T) {
@@ -288,6 +298,7 @@ func TestStoreAddMessageWithPartsAndReasoningContent(t *testing.T) {
 		conv.ConversationID,
 		"assistant",
 		parts,
+		"gpt-5.4",
 		"need to inspect the file first",
 		10,
 	)
@@ -309,6 +320,9 @@ func TestStoreAddMessageWithPartsAndReasoningContent(t *testing.T) {
 			"need to inspect the file first",
 		)
 	}
+	if msgs[0].ModelName != "gpt-5.4" {
+		t.Errorf("ModelName = %q, want %q", msgs[0].ModelName, "gpt-5.4")
+	}
 }
 
 func TestStoreGetMessageCount(t *testing.T) {

pkg/seahorse/types.go

@@ -22,6 +22,7 @@ type Message struct {
 	ConversationID   int64         `json:"conversationId"`
 	Role             string        `json:"role"`
 	Content          string        `json:"content"`
+	ModelName        string        `json:"modelName,omitempty"`
 	ReasoningContent string        `json:"reasoningContent,omitempty"`
 	TokenCount       int           `json:"tokenCount"`
 	CreatedAt        time.Time     `json:"createdAt"`
@@ -135,6 +136,7 @@ func EstimateMessageTokens(msg Message) int {
 	pm := providers.Message{
 		Role:             msg.Role,
 		Content:          msg.Content,
+		ModelName:        msg.ModelName,
 		ReasoningContent: msg.ReasoningContent,
 	}
 

pkg/session/jsonl_backend_test.go

@@ -66,6 +66,25 @@ func TestJSONLBackend_AddFullMessage(t *testing.T) {
 	}
 }
 
+func TestJSONLBackend_AddFullMessage_PreservesModelName(t *testing.T) {
+	b := newBackend(t)
+
+	msg := providers.Message{
+		Role:      "assistant",
+		Content:   "done",
+		ModelName: "gpt-5.4-mini",
+	}
+	b.AddFullMessage("s1", msg)
+
+	history := b.GetHistory("s1")
+	if len(history) != 1 {
+		t.Fatalf("got %d, want 1", len(history))
+	}
+	if history[0].ModelName != "gpt-5.4-mini" {
+		t.Fatalf("ModelName = %q, want %q", history[0].ModelName, "gpt-5.4-mini")
+	}
+}
+
 func TestJSONLBackend_Summary(t *testing.T) {
 	b := newBackend(t)
 

web/backend/api/session.go

@@ -50,6 +50,7 @@ type sessionChatMessage struct {
 	Role        string                  `json:"role"`
 	Content     string                  `json:"content"`
 	Kind        string                  `json:"kind,omitempty"`
+	ModelName   string                  `json:"model_name,omitempty"`
 	Media       []string                `json:"media,omitempty"`
 	Attachments []sessionChatAttachment `json:"attachments,omitempty"`
 	ToolCalls   []utils.VisibleToolCall `json:"tool_calls,omitempty"`
@@ -510,6 +511,7 @@ func sessionTranscriptMessages(
 			chatMsg := sessionChatMessage{
 				Role:        "user",
 				Content:     msg.Content,
+				ModelName:   msg.ModelName,
 				Media:       append([]string(nil), msg.Media...),
 				Attachments: attachments,
 			}
@@ -529,9 +531,10 @@ func sessionTranscriptMessages(
 
 			toolCallsMsg, hasToolCallsMsg := assistantToolCallsMessage(
 				msg.ToolCalls,
+				msg.ModelName,
 				toolFeedbackMaxArgsLength,
 			)
-			visibleToolMessages := visibleAssistantToolMessages(msg.ToolCalls)
+			visibleToolMessages := visibleAssistantToolMessages(msg.ToolCalls, msg.ModelName)
 
 			// Pico web chat can persist both visible `message` tool output and a
 			// later plain assistant reply in the same turn. Hide only the fixed
@@ -556,6 +559,7 @@ func sessionTranscriptMessages(
 			chatMsg := sessionChatMessage{
 				Role:        "assistant",
 				Content:     content,
+				ModelName:   msg.ModelName,
 				Media:       append([]string(nil), msg.Media...),
 				Attachments: attachments,
 			}
@@ -682,14 +686,16 @@ func assistantThoughtMessage(msg providers.Message) (sessionChatMessage, bool) {
 		return sessionChatMessage{}, false
 	}
 	return sessionChatMessage{
-		Role:    "assistant",
-		Content: reasoning,
-		Kind:    "thought",
+		Role:      "assistant",
+		Content:   reasoning,
+		Kind:      "thought",
+		ModelName: msg.ModelName,
 	}, true
 }
 
 func assistantToolCallsMessage(
 	toolCalls []providers.ToolCall,
+	modelName string,
 	toolFeedbackMaxArgsLength int,
 ) (sessionChatMessage, bool) {
 	if len(toolCalls) == 0 {
@@ -707,6 +713,7 @@ func assistantToolCallsMessage(
 	return sessionChatMessage{
 		Role:      "assistant",
 		Kind:      "tool_calls",
+		ModelName: modelName,
 		ToolCalls: visibleToolCalls,
 	}, true
 }
@@ -718,7 +725,7 @@ func visibleAssistantToolArgsPreview(
 	return utils.VisibleToolCallArgumentsPreview(tc, toolFeedbackMaxArgsLength)
 }
 
-func visibleAssistantToolMessages(toolCalls []providers.ToolCall) []sessionChatMessage {
+func visibleAssistantToolMessages(toolCalls []providers.ToolCall, modelName string) []sessionChatMessage {
 	if len(toolCalls) == 0 {
 		return nil
 	}
@@ -734,8 +741,9 @@ func visibleAssistantToolMessages(toolCalls []providers.ToolCall) []sessionChatM
 			continue
 		}
 		messages = append(messages, sessionChatMessage{
-			Role:    "assistant",
-			Content: content,
+			Role:      "assistant",
+			Content:   content,
+			ModelName: modelName,
 		})
 	}
 

web/backend/api/session_test.go

@@ -564,7 +564,7 @@ func TestHandleGetSession_ReconstructsThoughtFromAssistantReasoningContent(t *te
 	sessionKey := picoSessionPrefix + "detail-reasoning-content"
 	for _, msg := range []providers.Message{
 		{Role: "user", Content: "hello"},
-		{Role: "assistant", Content: "final visible answer", ReasoningContent: "internal chain of thought"},
+		{Role: "assistant", Content: "final visible answer", ModelName: "gpt-5.4", ReasoningContent: "internal chain of thought"},
 	} {
 		if err := store.AddFullMessage(nil, sessionKey, msg); err != nil {
 			t.Fatalf("AddFullMessage() error = %v", err)
@@ -597,9 +597,15 @@ func TestHandleGetSession_ReconstructsThoughtFromAssistantReasoningContent(t *te
 		resp.Messages[1].Kind != "thought" {
 		t.Fatalf("thought message = %#v, want assistant thought/internal chain of thought", resp.Messages[1])
 	}
+	if resp.Messages[1].ModelName != "gpt-5.4" {
+		t.Fatalf("thought model_name = %q, want %q", resp.Messages[1].ModelName, "gpt-5.4")
+	}
 	if resp.Messages[2].Role != "assistant" || resp.Messages[2].Content != "final visible answer" {
 		t.Fatalf("final message = %#v, want assistant/final visible answer", resp.Messages[2])
 	}
+	if resp.Messages[2].ModelName != "gpt-5.4" {
+		t.Fatalf("final model_name = %q, want %q", resp.Messages[2].ModelName, "gpt-5.4")
+	}
 }
 
 func TestHandleGetSession_ReconstructsRefreshMatrixForThoughtAndToolSummary(t *testing.T) {
@@ -725,8 +731,9 @@ func TestHandleGetSession_ReconstructsVisibleMessageToolOutputWithoutDuplicateSu
 	for _, msg := range []providers.Message{
 		{Role: "user", Content: "test"},
 		{
-			Role:    "assistant",
-			Content: "",
+			Role:      "assistant",
+			Content:   "",
+			ModelName: "gpt-5.4-mini",
 			ToolCalls: []providers.ToolCall{
 				{
 					ID:   "call_1",
@@ -771,9 +778,15 @@ func TestHandleGetSession_ReconstructsVisibleMessageToolOutputWithoutDuplicateSu
 		t.Fatalf("first message = %#v, want user/test", resp.Messages[0])
 	}
 	assertVisibleToolCallMessage(t, resp.Messages[1], "message")
+	if resp.Messages[1].ModelName != "gpt-5.4-mini" {
+		t.Fatalf("tool_calls model_name = %q, want %q", resp.Messages[1].ModelName, "gpt-5.4-mini")
+	}
 	if resp.Messages[2].Role != "assistant" || resp.Messages[2].Content != "visible tool output" {
 		t.Fatalf("assistant message = %#v, want visible tool output", resp.Messages[2])
 	}
+	if resp.Messages[2].ModelName != "gpt-5.4-mini" {
+		t.Fatalf("visible tool output model_name = %q, want %q", resp.Messages[2].ModelName, "gpt-5.4-mini")
+	}
 }
 
 func TestHandleGetSession_PreservesFinalAssistantReplyAfterMessageToolOutput(t *testing.T) {

web/frontend/src/api/sessions.ts

@@ -15,6 +15,7 @@ export interface SessionDetail {
     role: "user" | "assistant"
     content: string
     kind?: "normal" | "thought" | "tool_calls"
+    model_name?: string
     media?: string[]
     attachments?: {
       type?: "image" | "audio" | "video" | "file"

web/frontend/src/components/chat/assistant-message.tsx

@@ -33,6 +33,7 @@ interface AssistantMessageProps {
   content: string
   attachments?: ChatAttachment[]
   kind?: AssistantMessageKind
+  modelName?: string
   toolCalls?: ChatToolCall[]
   timestamp?: string | number
 }
@@ -41,6 +42,7 @@ export function AssistantMessage({
   content,
   attachments = [],
   kind = "normal",
+  modelName,
   toolCalls = [],
   timestamp = "",
 }: AssistantMessageProps) {
@@ -66,13 +68,20 @@ export function AssistantMessage({
   const copyMessageLabel = isCopied
     ? t("chat.copiedLabel")
     : t("chat.copyMessage")
+  const trimmedModelName = modelName?.trim() ?? ""
 
   return (
     <div className="group flex w-full flex-col gap-1.5">
       {!isCollapsedBlock && (
-        <div className="text-muted-foreground/60 flex items-center justify-between gap-2 px-1 text-xs opacity-70">
+          <div className="text-muted-foreground/60 flex items-center justify-between gap-2 px-1 text-xs opacity-70">
           <div className="flex items-center gap-2">
             <span>PicoClaw</span>
+            {trimmedModelName && (
+              <>
+                <span className="opacity-50">•</span>
+                <span>{trimmedModelName}</span>
+              </>
+            )}
             {formattedTimestamp && (
               <>
                 <span className="opacity-50">•</span>
@@ -104,6 +113,9 @@ export function AssistantMessage({
                   <IconTool className="size-3.5" />
                 )}
                 <span>{collapsedLabel}</span>
+                {trimmedModelName && (
+                  <span className="text-muted-foreground/45">{trimmedModelName}</span>
+                )}
               </div>
               <IconChevronDown
                 className={cn(

web/frontend/src/components/chat/chat-page.tsx

@@ -376,6 +376,7 @@ export function ChatPage() {
                     content={msg.content}
                     attachments={msg.attachments}
                     kind={msg.kind}
+                    modelName={msg.modelName}
                     toolCalls={msg.toolCalls}
                     timestamp={msg.timestamp}
                   />

web/frontend/src/features/chat/history.ts

@@ -50,6 +50,7 @@ export async function loadSessionMessages(
     role: message.role,
     content: message.content,
     kind: message.role === "assistant" ? (message.kind ?? "normal") : undefined,
+    modelName: message.model_name,
     toolCalls:
       message.role === "assistant"
         ? parseToolCallsValue(message.tool_calls)
@@ -86,7 +87,7 @@ function messageSignature(message: ChatMessage): string {
 
   return `${message.role}\u0000${message.content}\u0000${normalizeMessageTimestamp(
     message.timestamp,
-  )}\u0000${message.kind ?? ""}\u0000${attachmentSignature}\u0000${toolCallsSignature(
+  )}\u0000${message.kind ?? ""}\u0000${message.modelName ?? ""}\u0000${attachmentSignature}\u0000${toolCallsSignature(
     message.toolCalls,
   )}`
 }

web/frontend/src/features/chat/protocol.ts

@@ -83,6 +83,14 @@ function parseContextUsage(
   }
 }
 
+function parseModelName(payload: Record<string, unknown>): string | undefined {
+  if (typeof payload.model_name !== "string") {
+    return undefined
+  }
+  const modelName = payload.model_name.trim()
+  return modelName || undefined
+}
+
 export function handlePicoMessage(
   message: PicoMessage,
   expectedSessionId: string,
@@ -102,6 +110,7 @@ export function handlePicoMessage(
       const attachments = parseAttachments(payload)
       const contextUsage = parseContextUsage(payload)
       const isPlaceholder = payload.placeholder === true
+      const modelName = parseModelName(payload)
       const timestamp =
         message.timestamp !== undefined &&
         Number.isFinite(Number(message.timestamp))
@@ -116,6 +125,7 @@ export function handlePicoMessage(
             role: "assistant",
             content,
             kind,
+            ...(modelName ? { modelName } : {}),
             ...(toolCalls ? { toolCalls } : {}),
             attachments,
             timestamp,
@@ -135,6 +145,7 @@ export function handlePicoMessage(
       const messageId = payload.message_id as string
       const attachments = parseAttachments(payload)
       const contextUsage = parseContextUsage(payload)
+      const modelName = parseModelName(payload)
       const timestamp =
         message.timestamp !== undefined &&
         Number.isFinite(Number(message.timestamp))
@@ -160,6 +171,7 @@ export function handlePicoMessage(
               content,
               kind,
               toolCalls,
+              ...(modelName ? { modelName } : {}),
               ...(attachments ? { attachments } : {}),
             }
           })
@@ -178,6 +190,7 @@ export function handlePicoMessage(
               content,
               kind,
               toolCalls,
+              ...(modelName ? { modelName } : {}),
               ...(attachments ? { attachments } : {}),
               timestamp,
             },

web/frontend/src/store/chat.ts

@@ -44,6 +44,7 @@ export interface ChatMessage {
   content: string
   timestamp: number | string
   kind?: AssistantMessageKind
+  modelName?: string
   attachments?: ChatAttachment[]
   toolCalls?: ChatToolCall[]
 }