refactor(commands): consolidate /switch into commands package, fix ! prefix

Move /switch model and /switch channel handling from inline loop.go
logic into cmd_switch.go using the SubCommand + Deps pattern. This
removes the OutcomePassthrough branch in handleCommand entirely.

Also replace the hardcoded "/" prefix check with commands.HasCommandPrefix
so that "!" prefixed commands are correctly routed to the Executor.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

pkg/agent/loop.go

@@ -66,8 +66,6 @@ type processOptions struct {
 const (
 	defaultResponse           = "I've completed processing but have no response to give. Increase `max_tool_iterations` in config.json."
 	sessionKeyAgentPrefix     = "agent:"
-	switchCommandToken        = "/switch"
-	commandMentionSeparator   = "@"
 	metadataKeyAccountID      = "account_id"
 	metadataKeyGuildID        = "guild_id"
 	metadataKeyTeamID         = "team_id"
@@ -121,6 +119,28 @@ func NewAgentLoop(
 			}
 			return al.channelManager.GetEnabledChannels()
 		},
+		SwitchModel: func(value string) (string, error) {
+			defaultAgent := al.registry.GetDefaultAgent()
+			if defaultAgent == nil {
+				return "", fmt.Errorf("no default agent configured")
+			}
+			oldModel := defaultAgent.Model
+			defaultAgent.Model = value
+			if al.cfg != nil {
+				al.cfg.Agents.Defaults.ModelName = value
+				al.cfg.Agents.Defaults.Model = value
+			}
+			return oldModel, nil
+		},
+		SwitchChannel: func(value string) error {
+			if al.channelManager == nil {
+				return fmt.Errorf("channel manager not initialized")
+			}
+			if _, exists := al.channelManager.GetChannel(value); !exists && value != "cli" {
+				return fmt.Errorf("channel '%s' not found or not enabled", value)
+			}
+			return nil
+		},
 	}
 	al.cmdExecutor = commands.NewExecutor(
 		commands.NewRegistry(commands.BuiltinDefinitions(deps)),
@@ -1484,10 +1504,7 @@ func (al *AgentLoop) handleCommand(
 	ctx context.Context,
 	msg bus.InboundMessage,
 ) (string, bool) {
-	// Generic command routing is delegated to the centralized commands executor.
+	if !commands.HasCommandPrefix(msg.Content) {
-	// Session lifecycle commands are intentionally out of scope for this PR layer.
-	content := strings.TrimSpace(msg.Content)
-	if !strings.HasPrefix(content, "/") {
 		return "", false
 	}
 
@@ -1520,54 +1537,10 @@ func (al *AgentLoop) handleCommand(
 			return result.Reply, true
 		}
 		return "", true
-	case commands.OutcomePassthrough:
-		parts := strings.Fields(content)
-		if len(parts) == 0 {
-			return "", false
-		}
-		cmd := parts[0]
-		if at := strings.Index(cmd, commandMentionSeparator); at > 0 {
-			cmd = cmd[:at]
-		}
-		if cmd != switchCommandToken {
-			return "", false
-		}
-
-		args := parts[1:]
-		if len(args) < 3 || args[1] != "to" {
-			return "Usage: /switch [model|channel] to <name>", true
-		}
-		target := args[0]
-		value := args[2]
-
-		switch target {
-		case "model":
-			defaultAgent := al.registry.GetDefaultAgent()
-			if defaultAgent == nil {
-				return "No default agent configured", true
-			}
-			oldModel := defaultAgent.Model
-			defaultAgent.Model = value
-			if al.cfg != nil {
-				al.cfg.Agents.Defaults.ModelName = value
-				al.cfg.Agents.Defaults.Model = value
-			}
-			return fmt.Sprintf("Switched model from %s to %s", oldModel, value), true
-		case "channel":
-			if al.channelManager == nil {
-				return "Channel manager not initialized", true
-			}
-			if _, exists := al.channelManager.GetChannel(value); !exists && value != "cli" {
-				return fmt.Sprintf("Channel '%s' not found or not enabled", value), true
-			}
-			return fmt.Sprintf("Switched target channel to %s", value), true
 	default:
-			return fmt.Sprintf("Unknown switch target: %s", target), true
-		}
-	}
-
 		return "", false
 	}
+}
 
 func mapCommandError(result commands.ExecuteResult) string {
 	if result.Command == "" {

pkg/commands/builtin.go

@@ -8,5 +8,6 @@ func BuiltinDefinitions(deps *Deps) []Definition {
 		helpCommand(deps),
 		showCommand(deps),
 		listCommand(deps),
+		switchCommand(deps),
 	}
 }

pkg/commands/cmd_switch.go

@@ -0,0 +1,59 @@
+package commands
+
+import (
+	"context"
+	"fmt"
+)
+
+func switchCommand(deps *Deps) Definition {
+	return Definition{
+		Name:        "switch",
+		Description: "Switch model or channel",
+		SubCommands: []SubCommand{
+			{
+				Name:        "model",
+				Description: "Switch to a different model",
+				ArgsUsage:   "to <name>",
+				Handler: func(_ context.Context, req Request) error {
+					if req.Reply == nil {
+						return nil
+					}
+					if deps.SwitchModel == nil {
+						return req.Reply("Command unavailable in current context.")
+					}
+					// Parse: /switch model to <value>
+					value := nthToken(req.Text, 3) // tokens: [/switch, model, to, <value>]
+					if nthToken(req.Text, 2) != "to" || value == "" {
+						return req.Reply("Usage: /switch model to <name>")
+					}
+					oldModel, err := deps.SwitchModel(value)
+					if err != nil {
+						return req.Reply(err.Error())
+					}
+					return req.Reply(fmt.Sprintf("Switched model from %s to %s", oldModel, value))
+				},
+			},
+			{
+				Name:        "channel",
+				Description: "Switch to a different channel",
+				ArgsUsage:   "to <name>",
+				Handler: func(_ context.Context, req Request) error {
+					if req.Reply == nil {
+						return nil
+					}
+					if deps.SwitchChannel == nil {
+						return req.Reply("Command unavailable in current context.")
+					}
+					value := nthToken(req.Text, 3)
+					if nthToken(req.Text, 2) != "to" || value == "" {
+						return req.Reply("Usage: /switch channel to <name>")
+					}
+					if err := deps.SwitchChannel(value); err != nil {
+						return req.Reply(err.Error())
+					}
+					return req.Reply(fmt.Sprintf("Switched target channel to %s", value))
+				},
+			},
+		},
+	}
+}

pkg/commands/cmd_switch_test.go

@@ -0,0 +1,238 @@
+package commands
+
+import (
+	"context"
+	"fmt"
+	"testing"
+)
+
+func TestSwitchModel_Success(t *testing.T) {
+	deps := &Deps{
+		SwitchModel: func(value string) (string, error) {
+			return "old-model", nil
+		},
+	}
+	ex := NewExecutor(NewRegistry(BuiltinDefinitions(deps)))
+
+	var reply string
+	res := ex.Execute(context.Background(), Request{
+		Text: "/switch model to gpt-4",
+		Reply: func(text string) error {
+			reply = text
+			return nil
+		},
+	})
+	if res.Outcome != OutcomeHandled {
+		t.Fatalf("outcome=%v, want=%v", res.Outcome, OutcomeHandled)
+	}
+	want := "Switched model from old-model to gpt-4"
+	if reply != want {
+		t.Fatalf("reply=%q, want=%q", reply, want)
+	}
+}
+
+func TestSwitchModel_MissingToKeyword(t *testing.T) {
+	deps := &Deps{
+		SwitchModel: func(value string) (string, error) {
+			return "old", nil
+		},
+	}
+	ex := NewExecutor(NewRegistry(BuiltinDefinitions(deps)))
+
+	var reply string
+	res := ex.Execute(context.Background(), Request{
+		Text: "/switch model gpt-4",
+		Reply: func(text string) error {
+			reply = text
+			return nil
+		},
+	})
+	if res.Outcome != OutcomeHandled {
+		t.Fatalf("outcome=%v, want=%v", res.Outcome, OutcomeHandled)
+	}
+	if reply != "Usage: /switch model to <name>" {
+		t.Fatalf("reply=%q, want usage message", reply)
+	}
+}
+
+func TestSwitchModel_MissingValue(t *testing.T) {
+	deps := &Deps{
+		SwitchModel: func(value string) (string, error) {
+			return "old", nil
+		},
+	}
+	ex := NewExecutor(NewRegistry(BuiltinDefinitions(deps)))
+
+	var reply string
+	res := ex.Execute(context.Background(), Request{
+		Text: "/switch model to",
+		Reply: func(text string) error {
+			reply = text
+			return nil
+		},
+	})
+	if res.Outcome != OutcomeHandled {
+		t.Fatalf("outcome=%v, want=%v", res.Outcome, OutcomeHandled)
+	}
+	if reply != "Usage: /switch model to <name>" {
+		t.Fatalf("reply=%q, want usage message", reply)
+	}
+}
+
+func TestSwitchModel_Error(t *testing.T) {
+	deps := &Deps{
+		SwitchModel: func(value string) (string, error) {
+			return "", fmt.Errorf("model not found")
+		},
+	}
+	ex := NewExecutor(NewRegistry(BuiltinDefinitions(deps)))
+
+	var reply string
+	res := ex.Execute(context.Background(), Request{
+		Text: "/switch model to bad-model",
+		Reply: func(text string) error {
+			reply = text
+			return nil
+		},
+	})
+	if res.Outcome != OutcomeHandled {
+		t.Fatalf("outcome=%v, want=%v", res.Outcome, OutcomeHandled)
+	}
+	if reply != "model not found" {
+		t.Fatalf("reply=%q, want error message", reply)
+	}
+}
+
+func TestSwitchModel_NilDep(t *testing.T) {
+	deps := &Deps{}
+	ex := NewExecutor(NewRegistry(BuiltinDefinitions(deps)))
+
+	var reply string
+	res := ex.Execute(context.Background(), Request{
+		Text: "/switch model to gpt-4",
+		Reply: func(text string) error {
+			reply = text
+			return nil
+		},
+	})
+	if res.Outcome != OutcomeHandled {
+		t.Fatalf("outcome=%v, want=%v", res.Outcome, OutcomeHandled)
+	}
+	if reply != "Command unavailable in current context." {
+		t.Fatalf("reply=%q, want unavailable message", reply)
+	}
+}
+
+func TestSwitchChannel_Success(t *testing.T) {
+	deps := &Deps{
+		SwitchChannel: func(value string) error {
+			return nil
+		},
+	}
+	ex := NewExecutor(NewRegistry(BuiltinDefinitions(deps)))
+
+	var reply string
+	res := ex.Execute(context.Background(), Request{
+		Text: "/switch channel to telegram",
+		Reply: func(text string) error {
+			reply = text
+			return nil
+		},
+	})
+	if res.Outcome != OutcomeHandled {
+		t.Fatalf("outcome=%v, want=%v", res.Outcome, OutcomeHandled)
+	}
+	want := "Switched target channel to telegram"
+	if reply != want {
+		t.Fatalf("reply=%q, want=%q", reply, want)
+	}
+}
+
+func TestSwitchChannel_Error(t *testing.T) {
+	deps := &Deps{
+		SwitchChannel: func(value string) error {
+			return fmt.Errorf("channel '%s' not found", value)
+		},
+	}
+	ex := NewExecutor(NewRegistry(BuiltinDefinitions(deps)))
+
+	var reply string
+	res := ex.Execute(context.Background(), Request{
+		Text: "/switch channel to unknown",
+		Reply: func(text string) error {
+			reply = text
+			return nil
+		},
+	})
+	if res.Outcome != OutcomeHandled {
+		t.Fatalf("outcome=%v, want=%v", res.Outcome, OutcomeHandled)
+	}
+	if reply != "channel 'unknown' not found" {
+		t.Fatalf("reply=%q, want error message", reply)
+	}
+}
+
+func TestSwitchChannel_NilDep(t *testing.T) {
+	deps := &Deps{}
+	ex := NewExecutor(NewRegistry(BuiltinDefinitions(deps)))
+
+	var reply string
+	res := ex.Execute(context.Background(), Request{
+		Text: "/switch channel to telegram",
+		Reply: func(text string) error {
+			reply = text
+			return nil
+		},
+	})
+	if res.Outcome != OutcomeHandled {
+		t.Fatalf("outcome=%v, want=%v", res.Outcome, OutcomeHandled)
+	}
+	if reply != "Command unavailable in current context." {
+		t.Fatalf("reply=%q, want unavailable message", reply)
+	}
+}
+
+func TestSwitch_BangPrefix(t *testing.T) {
+	deps := &Deps{
+		SwitchModel: func(value string) (string, error) {
+			return "old", nil
+		},
+	}
+	ex := NewExecutor(NewRegistry(BuiltinDefinitions(deps)))
+
+	var reply string
+	res := ex.Execute(context.Background(), Request{
+		Text: "!switch model to gpt-4",
+		Reply: func(text string) error {
+			reply = text
+			return nil
+		},
+	})
+	if res.Outcome != OutcomeHandled {
+		t.Fatalf("! prefix: outcome=%v, want=%v", res.Outcome, OutcomeHandled)
+	}
+	if reply != "Switched model from old to gpt-4" {
+		t.Fatalf("! prefix: reply=%q, want success message", reply)
+	}
+}
+
+func TestSwitch_NoSubCommand(t *testing.T) {
+	deps := &Deps{}
+	ex := NewExecutor(NewRegistry(BuiltinDefinitions(deps)))
+
+	var reply string
+	res := ex.Execute(context.Background(), Request{
+		Text: "/switch",
+		Reply: func(text string) error {
+			reply = text
+			return nil
+		},
+	})
+	if res.Outcome != OutcomeHandled {
+		t.Fatalf("outcome=%v, want=%v", res.Outcome, OutcomeHandled)
+	}
+	// Should get usage message from executor's sub-command routing
+	if reply == "" {
+		t.Fatal("expected usage reply for bare /switch")
+	}
+}

pkg/commands/deps.go

@@ -11,4 +11,6 @@ type Deps struct {
 	GetModelInfo       func() (name, provider string)
 	ListAgentIDs       func() []string
 	GetEnabledChannels func() []string
+	SwitchModel        func(value string) (oldModel string, err error)
+	SwitchChannel      func(value string) error
 }

pkg/commands/dispatcher.go

@@ -65,6 +65,26 @@ func secondToken(input string) string {
 	return parts[1]
 }
 
+// HasCommandPrefix returns true if the input starts with a recognized
+// command prefix (e.g. "/" or "!").
+func HasCommandPrefix(input string) bool {
+	token := firstToken(input)
+	if token == "" {
+		return false
+	}
+	_, ok := trimCommandPrefix(token)
+	return ok
+}
+
+// nthToken returns the 0-indexed token from whitespace-split input.
+func nthToken(input string, n int) string {
+	parts := strings.Fields(strings.TrimSpace(input))
+	if n >= len(parts) {
+		return ""
+	}
+	return parts[n]
+}
+
 func normalizeCommandName(name string) string {
 	return strings.ToLower(strings.TrimSpace(name))
 }