Retain metrics-only sub-agent attribution

Co-authored-by: SivaKesava1 <11771739+SivaKesava1@users.noreply.github.com>
pelikhan · Oct 9, 2026 · Oct 8, 2026 · Oct 8, 2026 · Oct 8, 2026 · Oct 8, 2026
commit 2d4290883afd936ced6542e078e513fbabeab52a
diff --git a/pkg/cli/token_usage_subagent.go b/pkg/cli/token_usage_subagent.go
@@ -461,6 +461,7 @@ func isPiSubagentModel(entry TokenUsageEntry, models []string, resolver *modelId
 
 func accumulatePiMainUsage(main *AgentUsageBreakdown, entry TokenUsageEntry) {
 	credits := tokenUsageEntryCredits(entry)
+	servedModel := modelNameWithoutProvider(entry.Model)
 	main.Requests++
 	main.InputTokens += entry.InputTokens
 	main.OutputTokens += entry.OutputTokens
@@ -469,8 +470,9 @@ func accumulatePiMainUsage(main *AgentUsageBreakdown, entry TokenUsageEntry) {
 	main.ReasoningTokens += entry.ReasoningTokens
 	main.AIC += credits
 	main.TotalApiDurationMs += entry.DurationMs
+	main.ServedModels = appendUnique(main.ServedModels, servedModel)
 	main.Models = appendAgentModelUsage(main.Models, AgentModelUsage{
-		Model: entry.Model, ResolvedModel: normalizeModelIdentity(modelNameWithoutProvider(entry.Model)),
+		Model: entry.Model, ResolvedModel: normalizeModelIdentity(servedModel),
 		Requests: 1, TokenCoreMetrics: TokenCoreMetrics{
 			InputTokens: entry.InputTokens, OutputTokens: entry.OutputTokens,
 			CacheReadTokens: entry.CacheReadTokens, CacheWriteTokens: entry.CacheWriteTokens,

diff --git a/pkg/cli/token_usage_subagent_session.go b/pkg/cli/token_usage_subagent_session.go
@@ -571,16 +571,24 @@ func (models *subagentSessionModels) observeMetrics(data sessionSubagentData) er
 }
 
 func (models *subagentSessionModels) observeAgentMetric(agentID string, metric sessionSubagentAgentMetric) error {
-	if agentID != "main" && models.agents[agentID] == nil && metric.AgentName != "" {
-		name := firstNonEmptyModel(metric.AgentDisplayName, metric.AgentName)
-		models.agents[agentID] = &SubagentModelRequest{AgentName: name, InvocationCount: 1}
-	}
 	name := firstNonEmptyModel(metric.AgentDisplayName, metric.AgentName)
 	role := "subagent"
 	if agentID == "main" {
 		name, role = "main", "main"
-	} else if name == "" && models.agents[agentID] != nil {
-		name = models.agents[agentID].AgentName
+	} else {
+		if name == "" {
+			name = agentID
+		}
+		row := models.agents[agentID]
+		if row == nil {
+			row = &SubagentModelRequest{AgentName: name}
+			models.agents[agentID] = row
+		} else if row.AgentName == "" {
+			row.AgentName = name
+		}
+		if row.RequestedModel == "" {
+			row.RequestedModel = agentMetricRequestedModel(metric)
+		}
 	}
 	agentUsage := models.agentUsage[agentID]
 	if agentUsage == nil {
@@ -602,6 +610,23 @@ func (models *subagentSessionModels) observeAgentMetric(agentID string, metric s
 	return models.addAgentMetricModelUsage(agentID, metric, agentUsage)
 }
 
+func agentMetricRequestedModel(metric sessionSubagentAgentMetric) string {
+	models := make([]string, 0, len(metric.ModelMetrics))
+	for model := range metric.ModelMetrics {
+		models = append(models, model)
+	}
+	slices.Sort(models)
+	for _, model := range models {
+		if metric.ModelMetrics[model].Requests.Count != nil && *metric.ModelMetrics[model].Requests.Count > 0 {
+			return model
+		}
+	}
+	if len(models) > 0 {
+		return models[0]
+	}
+	return ""
+}
+
 func (models *subagentSessionModels) addAgentMetricModelUsage(agentID string, metric sessionSubagentAgentMetric, agentUsage *AgentUsageBreakdown) error {
 	counts := make(map[string]int)
 	actuals := make(map[string]SubagentModelActual)
@@ -1022,8 +1047,8 @@ func addSubagentRequestGroup(grouped map[subagentModelKey]SubagentModelRequest,
 	current := *row
 	current.EffectiveModel = ""
 	current.ReasonCode = ""
-	combined := grouped[key]
-	if combined.InvocationCount == 0 {
+	combined, exists := grouped[key]
+	if !exists {
 		combined = current
 	} else {
 		combined.InvocationCount += current.InvocationCount

diff --git a/pkg/cli/token_usage_subagent_session_test.go b/pkg/cli/token_usage_subagent_session_test.go
@@ -460,6 +460,43 @@
 	require.Zero(t, summary.AgentUsage[1].AIC)
 }
 
+func TestCopilotAgentMetricsWithoutLifecycleRetainAttribution(t *testing.T) {
+	root := t.TempDir()
+	require.NoError(t, os.MkdirAll(filepath.Join(root, "usage"), 0o755))
+	content := subagentSessionHeader +
+		subagentSessionRecord(`{"type":"session.init","data":{"sourceEngine":"copilot","sessionId":"metrics-only"}}`) +
+		subagentSessionRecord(`{"type":"session.shutdown","data":{"agentMetrics":`+strings.ReplaceAll(copilotSubagentIntegrationMetrics, "\n", "")+`}}`)
+	require.NoError(t, os.WriteFile(filepath.Join(root, "usage", "aw_session.jsonl"), []byte(content), 0o644))
+
+	_, _, parsedAgents, found, err := readSessionSubagentModelsDetailed(root)
+	require.NoError(t, err)
+	require.True(t, found)
+	require.Len(t, parsedAgents, 4)
+	summary := &TokenUsageSummary{}
+	augmentSubagentModelAttribution(root, summary)
+
+	require.Len(t, summary.AgentUsage, 4)
+	agents := make(map[string]AgentUsageBreakdown, len(summary.AgentUsage))
+	for _, agent := range summary.AgentUsage {
+		agents[agent.AgentName] = agent
+	}
+	require.InDelta(t, 389.122, agents["main"].AIC, 0.000001)
+	require.InDelta(t, 494.207, agents["subagent-research"].AIC, 0.000001)
+	require.InDelta(t, 40.977, agents["awf-routing"].AIC, 0.000001)
+	require.InDelta(t, 9.141, agents["ghaw-issues"].AIC, 0.000001)
+	require.Len(t, summary.SubagentModelRequests, 3)
+	for _, request := range summary.SubagentModelRequests {
+		require.Zero(t, request.InvocationCount)
+		require.Zero(t, request.CompletedCount)
+		require.Zero(t, request.FailedCount)
+		require.Zero(t, request.IncompleteCount)
+		require.Equal(t, "opus", request.RequestedModel)
+	}
+	require.Len(t, summary.SubagentModelActuals, 1)
+	require.Equal(t, 60, summary.SubagentModelActuals[0].Requests)
+	require.Equal(t, TokenCoreMetrics{InputTokens: 6000, OutputTokens: 600, CacheReadTokens: 60, CacheWriteTokens: 120}, summary.SubagentModelActuals[0].TokenCoreMetrics)
+}
+
 func TestPiUnifiedFixtureAttributesInterleavedRequestsFromFirewallEvents(t *testing.T) {
 	fixture := filepath.Join("testdata", "subagent_attribution", "pi-interleaved")
 	_, actuals, agents, found, err := readSessionSubagentModelsDetailed(fixture)
@@ -476,22 +513,28 @@
 	require.Equal(t, "z-1", entries[0].RequestID)

 	resolver := newModelIdentityResolver("")
 	agents = resolveAgentUsageModels(agents, resolver, tokenUsageEntryModels(entries)...)
 	summary := &TokenUsageSummary{AgentUsage: agents, AICFound: true, TotalAIC: 2.35}
 	matchPiAgentUsageCredits(summary, entries, resolver)
 	reconcileAgentUsageCredits(summary, entries)
 
 	creditsByAgent := make(map[string]float64)
 	requestsByAgent := make(map[string]int)
+	var mainAgent *AgentUsageBreakdown
 	for _, agent := range summary.AgentUsage {
 		creditsByAgent[agent.AgentName] = agent.AIC
 		requestsByAgent[agent.AgentName] = agent.Requests
+		if agent.AgentType == "main" {
+			mainAgent = &agent
+		}
 	}
 	require.InDelta(t, 0.9, creditsByAgent["a-reader"], 0.000001)
 	require.InDelta(t, 1.2, creditsByAgent["z-reader"], 0.000001)
 	require.InDelta(t, 0.25, creditsByAgent["main"], 0.000001)
 	require.Equal(t, 2, requestsByAgent["a-reader"])
 	require.Equal(t, 2, requestsByAgent["z-reader"])
 	require.Equal(t, 1, requestsByAgent["main"])
+	require.NotNil(t, mainAgent)
+	require.Equal(t, []string{"gpt-5.6-luna"}, mainAgent.ServedModels)
 	require.Empty(t, summary.Warnings)
 }