Report the mode of the built-in bash in the chat add-on list

A chat with no add-on that runs commands could not tell a person
whether the server's built-in bash was off or simply not selected.
The add-on list now carries commands_host_exec (off, ask or on), a
read-only copy of the chats_host_exec setting as it applies now.

Assisted-by: Claude:claude-sonnet-5-5

core/http/endpoints/studio/addons.go

@@ -17,13 +17,13 @@ func addonList(c echo.Context, h *Handlers) error {
 	if err != nil {
 		return failFor(c, err)
 	}
-	return writeAddonList(c, list, cmds)
+	return writeAddonList(c, h, list, cmds)
 }
 
-func writeAddonList(c echo.Context, list []studiosvc.AddonInfo, cmds studiosvc.Commands) error {
+func writeAddonList(c echo.Context, h *Handlers, list []studiosvc.AddonInfo, cmds studiosvc.Commands) error {
 	out := schema.ChatsAddonList{Addons: make([]schema.ChatsAddon, 0, len(list)), Commands: string(cmds.State), CommandsReason: cmds.Reason,
 		CommandsIsolation: cmds.Isolation, CommandsProvider: cmds.Provider, CommandsConsent: cmds.Consent,
-		CommandsFallback: cmds.Fallback, CommandsFallbackReason: cmds.FallbackReason}
+		CommandsFallback: cmds.Fallback, CommandsFallbackReason: cmds.FallbackReason, CommandsHostExec: h.svc.HostExecMode()}
 	if v := cmds.ExecutionStatus; v != nil {
 		out.ExecutionStatus = &schema.ChatsExecutionStatus{Readiness: v.Readiness, Isolation: v.Isolation, Explanation: v.Explanation, UnknownReason: v.UnknownReason, Generation: v.Generation, Incarnation: v.Incarnation}
 	}
@@ -49,7 +49,7 @@ func addonOut(a studiosvc.AddonInfo) schema.ChatsAddon {
 
 // ListChatAddons lists the add-ons a chat can use.
 // @Summary List the add-ons a chat can use.
-// @Description The add-ons whose tools the signed-in user may use now, each with the chat's switch, and whether the chat can run commands at its next turn (commands: available, off, unavailable, none, or switched_off when the chat switched the built-in group shell off). When commands is available, commands_provider says who serves bash (builtin: directly on this machine with no isolation and with its network, or the add-on's ID) and commands_isolation says isolated or host; commands_consent is ask when each command waits for a yes in the chat, and commands_fallback names an add-on that would serve but does not (commands_fallback_reason: off, or why it cannot run). Without the add-on host the list is empty.
+// @Description The add-ons whose tools the signed-in user may use now, each with the chat's switch, and whether the chat can run commands at its next turn (commands: available, off, unavailable, none, or switched_off when the chat switched the built-in group shell off). When commands is available, commands_provider says who serves bash (builtin: directly on this machine with no isolation and with its network, or the add-on's ID) and commands_isolation says isolated or host; commands_consent is ask when each command waits for a yes in the chat, and commands_fallback names an add-on that would serve but does not (commands_fallback_reason: off, or why it cannot run). commands_host_exec is the mode of chats_host_exec now (off, ask or on), so a client can say that the built-in bash is off when commands is none. Without the add-on host the list is empty.
 // @Tags chats
 // @Param id path string true "conversation id"
 // @Success 200 {object} schema.ChatsAddonList "The add-ons and their switches"

core/http/endpoints/studio/draft.go

@@ -82,7 +82,7 @@ func (h *Handlers) DraftAddons(c echo.Context) error {
 	if err != nil {
 		return failFor(c, err)
 	}
-	return writeAddonList(c, list, cmds)
+	return writeAddonList(c, h, list, cmds)
 }
 
 // draftSwitches reads the switches of a draft from the query: comma-separated

core/schema/chats.go

@@ -934,6 +934,10 @@ type ChatsAddonList struct {
 	// CommandsFallbackReason says why: off, or the add-on's reason.
 	CommandsFallback       string `json:"commands_fallback,omitempty"`
 	CommandsFallbackReason string `json:"commands_fallback_reason,omitempty"`
+	// CommandsHostExec is the mode of the setting chats_host_exec as it applies
+	// now (off, ask or on), so a client can say that the built-in bash is off
+	// when no add-on runs commands. Every signed-in user may read it.
+	CommandsHostExec string `json:"commands_host_exec,omitempty"`
 }
 
 // ChatsHostExecConsent answers the card that asks to run one command on this

core/services/studio/hostbash.go

@@ -86,6 +86,10 @@ func (s *Service) hostExecMode() string {
 	return hostexec.ModeOff
 }
 
+// HostExecMode is the mode of chats_host_exec as it applies now: off, ask or
+// on. A server with no such setting reads as off.
+func (s *Service) HostExecMode() string { return s.hostExecMode() }
+
 func (s *Service) isAdmin(ctx context.Context, user string) bool {
 	if s.d.IsAdmin == nil {
 		return true // no accounts: the one person is the administrator