fix(pricing): correct gpt-5.6-sol rates and add the daybreak blue alias

copilot.go

@@ -558,7 +558,7 @@ func (CopilotHarness) DefaultModels() []ModelDefault {
 	// entry as the default. Dotted Anthropic IDs are distinct from Claude Code's
 	// hyphenated IDs.
 	return []ModelDefault{
-		{Name: "GPT-5.6 Sol", ID: "gpt-5.6-sol"},
+		{Name: "GPT-5.6 Sol", ID: modelGPT56SolID},
 		{Name: "Claude Sonnet 5", ID: modelClaudeSonnet5ID},
 		{Name: "Claude Opus 5", ID: modelClaudeOpus5ID, Tier: modelTierMax},
 		{Name: "Claude Opus 4.8", ID: "claude-opus-4.8"},

harness.go

@@ -18,6 +18,8 @@ const (
 	modelGPT54MiniID     = "gpt-5.4-mini"
 	modelGPT54ID         = "gpt-5.4"
 	modelGPT55ID         = "gpt-5.5"
+	modelGPT56SolID      = "gpt-5.6-sol"
+	modelDaybreakBlueID  = "gpt-daybreak-blue-latest"
 
 	modelTierMid  = "mid"
 	modelTierHigh = "high"

pricing.go

@@ -12,7 +12,7 @@ type modelPrice struct {
 // no dollar amount. Rows for backends that report cost directly remain here so
 // tests can require every default model to have a known price.
 //
-// Prices are USD rates per million tokens as of 2026-08. Copilot-only rows use
+// Prices are USD rates per million tokens. Copilot-only rows use
 // the token prices returned by CLI 1.0.80's models.list, converting one AI
 // credit to $0.01. Update this table with each backend's DefaultModels list.
 //
@@ -38,7 +38,9 @@ var modelPricing = map[string]modelPrice{
 	"claude-haiku-4.5":  {In: 1.00, Out: 5.00, CachedIn: 0.10, CacheWrite: 1.25},
 
 	// OpenAI
-	"gpt-5.6-sol":     {In: 2.00, Out: 10.00, CachedIn: 0.20, CacheWrite: 2.50},
+	// Sol's promotional standard rates apply at least through 2026-11-21; recheck then.
+	// https://developers.openai.com/api/docs/pricing
+	modelGPT56SolID:   {In: 4.00, Out: 20.00, CachedIn: 0.40, CacheWrite: 5.00},
 	"gpt-5.6-terra":   {In: 2.00, Out: 12.00, CachedIn: 0.20, CacheWrite: 2.50},
 	"gpt-5.6-luna":    {In: 0.20, Out: 1.20, CachedIn: 0.02, CacheWrite: 0.25},
 	modelGPT55ID:      {In: 5.00, Out: 30.00, CachedIn: 0.50},
@@ -68,7 +70,13 @@ const perMillion = 1e6
 // subset. CacheWriteTokens is separate only for models with a dedicated write
 // rate; it remains ordinary input when CacheWrite is zero.
 func CostFromUsage(model string, usage Usage) float64 {
-	price, ok := modelPricing[normalizeModelID(model)]
+	model = normalizeModelID(model)
+	// Daybreak Blue currently aliases Sol and shares its pricing.
+	// https://developers.openai.com/api/docs/models/gpt-daybreak-blue-latest
+	if model == modelDaybreakBlueID {
+		model = modelGPT56SolID
+	}
+	price, ok := modelPricing[model]
 	if !ok {
 		return 0
 	}

pricing_test.go

@@ -0,0 +1,39 @@
+package harness
+
+import (
+	"math"
+	"testing"
+)
+
+func TestCostFromUsage_gpt56SolAndDaybreakBasePricing(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name  string
+		usage Usage
+		want  float64
+	}{
+		{"uncached input", Usage{InputTokens: 100_000}, 0.40},
+		{"output", Usage{OutputTokens: 10_000}, 0.20},
+		{"cache reads", Usage{InputTokens: 100_000, CacheReadTokens: 100_000}, 0.04},
+		{"cache writes", Usage{InputTokens: 100_000, CacheWriteTokens: 100_000}, 0.50},
+		{"standard scan", Usage{InputTokens: 100_000, OutputTokens: 10_000}, 0.60},
+		{"mixed", Usage{InputTokens: 100_000, OutputTokens: 10_000, CacheReadTokens: 10_000, CacheWriteTokens: 20_000}, 0.584},
+	}
+	for _, model := range []struct{ name, id string }{
+		{"sol", "gpt-5.6-sol"},
+		{"sol_normalized", "openai/gpt-5.6-sol[1m]"},
+		{"daybreak", "gpt-daybreak-blue-latest"},
+		{"daybreak_normalized", "openai/gpt-daybreak-blue-latest[1m]"},
+	} {
+		t.Run(model.name, func(t *testing.T) {
+			for _, tt := range tests {
+				t.Run(tt.name, func(t *testing.T) {
+					if got := CostFromUsage(model.id, tt.usage); math.Abs(got-tt.want) > 1e-9 {
+						t.Errorf("CostFromUsage(%q, %+v) = %v, want %v", model.id, tt.usage, got, tt.want)
+					}
+				})
+			}
+		})
+	}
+}