agent: Pi offers xhigh and max for models that have them

Pi shows xhigh and max only for models whose thinkingLevelMap names them,
and magpie wrote just "reasoning", so a model whose top level is max (GLM-5.3,
DeepSeek) stopped at high and a max setting was sent as high (#5). Checked on
the wire: --thinking max sent reasoning_effort high before, max after. Picking
the model or thinking level in magpie again rewrites Pi's models.json.

internal/agent/agents.go

@@ -163,7 +163,11 @@ func magpieProviderJSON(shape string) any {
 		var ms []map[string]any
 		for _, m := range models {
 			// reasoning lets Pi offer its thinking levels for the model
-			ms = append(ms, map[string]any{"id": m.ID, "name": m.Name, "reasoning": len(m.Efforts) > 0})
+			e := map[string]any{"id": m.ID, "name": m.Name, "reasoning": len(m.Efforts) > 0}
+			if levels := piThinkingLevels(m.Efforts); levels != nil {
+				e["thinkingLevelMap"] = levels
+			}
+			ms = append(ms, e)
 		}
 		if ms == nil {
 			ms = []map[string]any{}
@@ -173,6 +177,22 @@ func magpieProviderJSON(shape string) any {
 	return nil
 }
 
+// piThinkingLevels is the thinkingLevelMap for a model's efforts. Pi offers
+// xhigh and max only for models that map them, so without it a model whose
+// top level is max stopped at high in Pi.
+func piThinkingLevels(efforts []string) map[string]any {
+	var levels map[string]any
+	for _, e := range efforts {
+		if e == "xhigh" || e == "max" {
+			if levels == nil {
+				levels = map[string]any{}
+			}
+			levels[e] = e
+		}
+	}
+	return levels
+}
+
 func opencode(home, cfg string) *Agent {
 	dir := filepath.Join(cfg, "opencode")
 	path := filepath.Join(dir, "opencode.json")

internal/agent/pi_test.go

@@ -0,0 +1,23 @@
+package agent
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestPiThinkingLevels(t *testing.T) {
+	for _, c := range []struct {
+		efforts []string
+		want    map[string]any
+	}{
+		{[]string{"low", "high", "max"}, map[string]any{"max": "max"}},
+		{[]string{"low", "medium", "high", "xhigh"}, map[string]any{"xhigh": "xhigh"}},
+		{[]string{"none", "low", "high", "xhigh", "max"}, map[string]any{"xhigh": "xhigh", "max": "max"}},
+		{[]string{"low", "medium", "high"}, nil},
+		{nil, nil},
+	} {
+		if got := piThinkingLevels(c.efforts); !reflect.DeepEqual(got, c.want) {
+			t.Errorf("%v: got %v, want %v", c.efforts, got, c.want)
+		}
+	}
+}