provider: a Codex warm-up asks the account's cheapest model (#604) — warmModel took a model with mini in its id or else the first listed, and a GPT-6 account lists no mini and starts with the flagship gpt-6.1-sol. warmPick takes the cheapest by list price (the model's own, else models.dev's openai price), and with no price known a mini, then a luna (GPT-6's cheap one), then the first. TestWarmPick.

internal/provider/codex_warmup.go

@@ -350,7 +350,7 @@ func warmCodexLogin(ctx context.Context, user string) error {
 }
 
 // warmModel is the model a warm-up asks, and at what effort: the account's
-// smallest (a mini) or else the first it lists, at low.
+// cheapest (warmPick), at low.
 func warmModel(user string) (model, effort string, err error) {
 	ms, _, ok := catalog.Live(accountModels("codex", user))
 	if !ok {
@@ -362,10 +362,7 @@ func warmModel(user string) (model, effort string, err error) {
 	if len(ms) == 0 {
 		return "", "", errors.New("no Codex model is known yet")
 	}
-	m := ms[0]
-	if i := slices.IndexFunc(ms, func(m catalog.Model) bool { return strings.Contains(m.ID, "mini") }); i >= 0 {
-		m = ms[i]
-	}
+	m := warmPick(ms, func(id string) (catalog.Price, bool) { return catalog.PricedBy([]string{"openai"}, id) })
 	switch {
 	case slices.Contains(m.Efforts, "low"):
 		effort = "low"
@@ -375,6 +372,34 @@ func warmModel(user string) (model, effort string, err error) {
 	return m.ID, effort, nil
 }
 
+// warmPick is the cheapest of an account's models, by its list price where
+// models.dev has one (#604: GPT-6's cheap one is gpt-6-luna; the list
+// has no mini and starts with the flagship gpt-6.1-sol); with no price
+// known, a mini, else a luna, else the first it lists.
+func warmPick(ms []catalog.Model, price func(id string) (catalog.Price, bool)) catalog.Model {
+	best, cost := -1, 0.0
+	for i, m := range ms {
+		p, ok := catalog.Price{}, false
+		if m.Price != nil {
+			p, ok = *m.Price, true
+		} else {
+			p, ok = price(m.ID)
+		}
+		if c := p.Input + p.Output; ok && c > 0 && (best < 0 || c < cost) {
+			best, cost = i, c
+		}
+	}
+	if best >= 0 {
+		return ms[best]
+	}
+	for _, word := range []string{"mini", "luna"} {
+		if i := slices.IndexFunc(ms, func(m catalog.Model) bool { return strings.Contains(m.ID, word) }); i >= 0 {
+			return ms[i]
+		}
+	}
+	return ms[0]
+}
+
 // warmCodex sends one "hi" to the ChatGPT backend as a Codex account's
 // requests go (codexBody: Codex's instructions, not stored), and reads the
 // reply to its end.

internal/provider/codex_warmup_test.go

@@ -12,6 +12,8 @@ import (
 	"sync"
 	"testing"
 	"time"
+
+	"github.com/yetone/magpie/internal/catalog"
 )
 
 const (
@@ -280,3 +282,38 @@ func TestCodexWarmRequest(t *testing.T) {
 		t.Fatalf("not kept: %v", CodexWarmed())
 	}
 }
+
+// #604: the warm-up asks the cheapest model, by price where it is known,
+// else a mini, else a luna, else the first listed.
+func TestWarmPick(t *testing.T) {
+	ids := func(ids ...string) []catalog.Model {
+		ms := make([]catalog.Model, len(ids))
+		for i, id := range ids {
+			ms[i] = catalog.Model{ID: id}
+		}
+		return ms
+	}
+	prices := map[string]catalog.Price{
+		"gpt-6.1-sol": {Input: 2, Output: 10}, "gpt-6-astra": {Input: 10, Output: 50},
+		"gpt-6-luna": {Input: 0.1, Output: 0.5}, "gpt-5.6-luna": {Input: 0.2, Output: 1.2},
+	}
+	priced := func(id string) (catalog.Price, bool) { p, ok := prices[id]; return p, ok }
+	none := func(string) (catalog.Price, bool) { return catalog.Price{}, false }
+	gpt6 := ids("gpt-6.1-sol", "gpt-6-astra", "gpt-6-sol", "gpt-6-luna", "gpt-5.6-sol", "gpt-5.6-terra", "gpt-5.6-luna", "gpt-5.5")
+	for _, c := range []struct {
+		name  string
+		ms    []catalog.Model
+		price func(string) (catalog.Price, bool)
+		want  string
+	}{
+		{"priced", gpt6, priced, "gpt-6-luna"},
+		{"no prices: a luna", gpt6, none, "gpt-6-luna"},
+		{"no prices: a mini first", ids("gpt-5-codex", "gpt-5-codex-mini", "gpt-6-luna"), none, "gpt-5-codex-mini"},
+		{"no prices, no cheap name", ids("gpt-6.1-sol", "gpt-6-sol"), none, "gpt-6.1-sol"},
+		{"the model's own price first", []catalog.Model{{ID: "gpt-6.1-sol"}, {ID: "x", Price: &catalog.Price{Input: 0.01, Output: 0.01}}}, priced, "x"},
+	} {
+		if got := warmPick(c.ms, c.price).ID; got != c.want {
+			t.Errorf("%s: %s, want %s", c.name, got, c.want)
+		}
+	}
+}