fix(agent): normalize subagent openrouter model ids

pkg/agent/loop.go

@@ -285,7 +285,11 @@ func registerSharedTools(
 		spawnEnabled := cfg.Tools.IsToolEnabled("spawn")
 		spawnStatusEnabled := cfg.Tools.IsToolEnabled("spawn_status")
 		if (spawnEnabled || spawnStatusEnabled) && cfg.Tools.IsToolEnabled("subagent") {
-			subagentManager := tools.NewSubagentManager(provider, agent.Model, agent.Workspace)
+			subagentManager := tools.NewSubagentManager(
+				provider,
+				resolveSubagentDefaultModel(agent),
+				agent.Workspace,
+			)
 			subagentManager.SetLLMOptions(agent.MaxTokens, agent.Temperature)
 
 			// Set the spawner that links into AgentLoop's turnState
@@ -377,6 +381,16 @@ func registerSharedTools(
 	}
 }
 
+func resolveSubagentDefaultModel(agent *AgentInstance) string {
+	if agent == nil {
+		return ""
+	}
+	if len(agent.Candidates) > 0 && strings.TrimSpace(agent.Candidates[0].Model) != "" {
+		return strings.TrimSpace(agent.Candidates[0].Model)
+	}
+	return agent.Model
+}
+
 func (al *AgentLoop) Run(ctx context.Context) error {
 	al.running.Store(true)
 

pkg/agent/subagent_default_model_test.go

@@ -0,0 +1,36 @@
+package agent
+
+import (
+	"testing"
+
+	"github.com/sipeed/picoclaw/pkg/providers"
+)
+
+func TestResolveSubagentDefaultModel(t *testing.T) {
+	t.Run("prefers resolved candidate model", func(t *testing.T) {
+		agent := &AgentInstance{
+			Model: "openrouter/minimax/minimax-m2.5",
+			Candidates: []providers.FallbackCandidate{
+				{Provider: "openrouter", Model: "minimax/minimax-m2.5"},
+			},
+		}
+
+		if got := resolveSubagentDefaultModel(agent); got != "minimax/minimax-m2.5" {
+			t.Fatalf("resolveSubagentDefaultModel() = %q, want %q", got, "minimax/minimax-m2.5")
+		}
+	})
+
+	t.Run("falls back to raw agent model when no candidates exist", func(t *testing.T) {
+		agent := &AgentInstance{Model: "claude-sonnet-4.6"}
+
+		if got := resolveSubagentDefaultModel(agent); got != "claude-sonnet-4.6" {
+			t.Fatalf("resolveSubagentDefaultModel() = %q, want %q", got, "claude-sonnet-4.6")
+		}
+	})
+
+	t.Run("returns empty string for nil agent", func(t *testing.T) {
+		if got := resolveSubagentDefaultModel(nil); got != "" {
+			t.Fatalf("resolveSubagentDefaultModel(nil) = %q, want empty string", got)
+		}
+	})
+}