ekg m2: rank fallback providers by recent success/error history and record provider outcomes

pkg/agent/loop.go

@@ -343,18 +343,30 @@ func (al *AgentLoop) lockSessionRun(sessionKey string) func() {
 	return func() { mu.Unlock() }
 }
 
-func (al *AgentLoop) tryFallbackProviders(ctx context.Context, messages []providers.Message, toolDefs []providers.ToolDefinition, options map[string]interface{}, primaryErr error) (*providers.LLMResponse, error) {
+func (al *AgentLoop) tryFallbackProviders(ctx context.Context, msg bus.InboundMessage, messages []providers.Message, toolDefs []providers.ToolDefinition, options map[string]interface{}, primaryErr error) (*providers.LLMResponse, error) {
 	if len(al.providerNames) <= 1 {
 		return nil, primaryErr
 	}
 	lastErr := primaryErr
-	for i := 1; i < len(al.providerNames); i++ {
-		name := al.providerNames[i]
+	candidates := append([]string(nil), al.providerNames[1:]...)
+	if al.ekg != nil {
+		candidates = al.ekg.RankProviders(candidates)
+	}
+	for _, name := range candidates {
 		p, ok := al.providerPool[name]
 		if !ok || p == nil {
 			continue
 		}
 		resp, err := p.Chat(ctx, messages, toolDefs, al.model, options)
+		if al.ekg != nil {
+			st := "success"
+			lg := "fallback provider success"
+			if err != nil {
+				st = "error"
+				lg = err.Error()
+			}
+			al.ekg.Record(ekg.Event{Session: msg.SessionKey, Channel: msg.Channel, Source: "provider_fallback", Status: st, Provider: name, Model: al.model, Log: lg})
+		}
 		if err == nil {
 			logger.WarnCF("agent", "LLM fallback provider switched", map[string]interface{}{"provider": name})
 			return resp, nil
@@ -753,7 +765,7 @@ func (al *AgentLoop) processMessage(ctx context.Context, msg bus.InboundMessage)
 		}
 
 		if err != nil {
-			if fb, ferr := al.tryFallbackProviders(ctx, messages, providerToolDefs, options, err); ferr == nil && fb != nil {
+			if fb, ferr := al.tryFallbackProviders(ctx, msg, messages, providerToolDefs, options, err); ferr == nil && fb != nil {
 				response = fb
 				err = nil
 			} else {
@@ -1096,7 +1108,7 @@ func (al *AgentLoop) processSystemMessage(ctx context.Context, msg bus.InboundMe
 		response, err := al.provider.Chat(ctx, messages, providerToolDefs, al.model, options)
 
 		if err != nil {
-			if fb, ferr := al.tryFallbackProviders(ctx, messages, providerToolDefs, options, err); ferr == nil && fb != nil {
+			if fb, ferr := al.tryFallbackProviders(ctx, msg, messages, providerToolDefs, options, err); ferr == nil && fb != nil {
 				response = fb
 				err = nil
 			} else {

pkg/ekg/engine.go

@@ -6,19 +6,22 @@ import (
 	"os"
 	"path/filepath"
 	"regexp"
+	"sort"
 	"strings"
 	"time"
 )
 
 type Event struct {
-	Time    string `json:"time"`
-	TaskID  string `json:"task_id,omitempty"`
-	Session string `json:"session,omitempty"`
-	Channel string `json:"channel,omitempty"`
-	Source  string `json:"source,omitempty"`
-	Status  string `json:"status"` // success|error|suppressed
-	ErrSig  string `json:"errsig,omitempty"`
-	Log     string `json:"log,omitempty"`
+	Time     string `json:"time"`
+	TaskID   string `json:"task_id,omitempty"`
+	Session  string `json:"session,omitempty"`
+	Channel  string `json:"channel,omitempty"`
+	Source   string `json:"source,omitempty"`
+	Status   string `json:"status"` // success|error|suppressed
+	Provider string `json:"provider,omitempty"`
+	Model    string `json:"model,omitempty"`
+	ErrSig   string `json:"errsig,omitempty"`
+	Log      string `json:"log,omitempty"`
 }
 
 type SignalContext struct {
@@ -67,6 +70,8 @@ func (e *Engine) Record(ev Event) {
 	ev.Channel = strings.TrimSpace(ev.Channel)
 	ev.Source = strings.TrimSpace(ev.Source)
 	ev.Status = strings.TrimSpace(strings.ToLower(ev.Status))
+	ev.Provider = strings.TrimSpace(ev.Provider)
+	ev.Model = strings.TrimSpace(ev.Model)
 	if ev.ErrSig == "" && ev.Log != "" {
 		ev.ErrSig = NormalizeErrorSignature(ev.Log)
 	}
@@ -169,6 +174,43 @@ var (
 	reSpace   = regexp.MustCompile(`\s+`)
 )
 
+func (e *Engine) RankProviders(candidates []string) []string {
+	if len(candidates) <= 1 || e == nil {
+		return append([]string(nil), candidates...)
+	}
+	events := e.readRecentEvents()
+	score := map[string]float64{}
+	for _, c := range candidates {
+		score[c] = 0
+	}
+	for _, ev := range events {
+		p := strings.TrimSpace(ev.Provider)
+		if p == "" {
+			continue
+		}
+		if _, ok := score[p]; !ok {
+			continue
+		}
+		switch strings.ToLower(strings.TrimSpace(ev.Status)) {
+		case "success":
+			score[p] += 1.0
+		case "suppressed":
+			score[p] += 0.2
+		case "error":
+			score[p] -= 1.0
+		}
+	}
+	ordered := append([]string(nil), candidates...)
+	sort.SliceStable(ordered, func(i, j int) bool {
+		si, sj := score[ordered[i]], score[ordered[j]]
+		if si == sj {
+			return ordered[i] < ordered[j]
+		}
+		return si > sj
+	})
+	return ordered
+}
+
 func NormalizeErrorSignature(s string) string {
 	s = strings.TrimSpace(strings.ToLower(s))
 	if s == "" {