v0.12.1

The guardrails' judge served and watched without server init.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -22,6 +22,37 @@ is only released once its **exit criterion** is met, not when its code lands.
 Until v1.0.0 the minor version is the breaking one: configuration formats and Go
 APIs change between minors without a deprecation period.
 
+## v0.12.1 — 2026-10-06
+
+The guardrails' judge, served and watched without server init: a judge
+missing, served as the wrong kind of model, or not answering is said on
+`ctl status` and the console, and `llmgw ctl guard judge enable` puts it
+right. Nothing to do to upgrade.
+
+### Added
+
+- **`llmgw ctl guard judge status` and `enable`**: each judge model the
+  policies ask, whether it is in the catalog, as a judge, with replicas
+  ready and answering — and serving the missing one, Llama Guard 3 1B on
+  CPUs under the name the policies give it, with `--replace` for a model of
+  that name that is not a judge. No more `server init` to put a judge back.
+  Also **Do → Serve the guardrails' judge** in the console.
+- **A missing or broken judge is said where it is looked for**: `llmgw ctl
+  status` and the console's Overview list each judge with a problem — not in
+  the catalog, not a judge, no replica ready, or failing to answer — and
+  what that does to requests (refused or unjudged).
+
+### Fixed
+
+- **A Llama Guard file served from the mirror page is the judge**: it was
+  added as a model clients use, under whatever name the form had, so the
+  policies never found it and refused everything they judged
+  (`guard_unavailable`). It is now added as a judge, under the name the
+  policies ask.
+- **`ctl` says so when the API answers with a page**: a command a control
+  plane does not know — the leader on an older release, through a standby —
+  failed with "invalid character '<'"; it now says which and why.
+
 ## v0.12.0 — 2026-10-06
 
 A minor version, because where the configuration lives changes: everything in

docs/admin-api.openapi.json

@@ -894,6 +894,36 @@
         }
       }
     },
+    "/api/v1/guard/judges": {
+      "get": {
+        "operationId": "getGuardJudges",
+        "summary": "The judge models the policies ask, and what is wrong with each",
+        "tags": [
+          "guard"
+        ],
+        "responses": {
+          "200": {
+            "description": "OK",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "type": "array",
+                  "items": {
+                    "$ref": "#/components/schemas/JudgeView"
+                  }
+                }
+              }
+            }
+          },
+          "401": {
+            "$ref": "#/components/responses/Unauthorized"
+          },
+          "default": {
+            "$ref": "#/components/responses/Error"
+          }
+        }
+      }
+    },
     "/api/v1/jobs": {
       "get": {
         "operationId": "getJobs",
@@ -4359,6 +4389,52 @@
           }
         }
       },
+      "JudgeView": {
+        "type": "object",
+        "description": "JudgeView is one judge model the guardrail policies ask, and whether it can answer them.",
+        "properties": {
+          "model": {
+            "type": "string"
+          },
+          "policies": {
+            "type": "array",
+            "items": {
+              "type": "string"
+            },
+            "description": "Policies are those that ask it; Closed those that refuse what it cannot read (fail: closed)."
+          },
+          "closed": {
+            "type": "array",
+            "items": {
+              "type": "string"
+            }
+          },
+          "in_catalog": {
+            "type": "boolean",
+            "description": "InCatalog is whether a model of that name is in the catalog, and Judge whether it is there as a judge (role: guard)."
+          },
+          "judge": {
+            "type": "boolean"
+          },
+          "ready_replicas": {
+            "type": "integer"
+          },
+          "wanted_replicas": {
+            "type": "integer"
+          },
+          "last_error": {
+            "type": "string",
+            "description": "LastError is its last failure to give a verdict, if any."
+          },
+          "last_error_at": {
+            "type": "string"
+          },
+          "problem": {
+            "type": "string",
+            "description": "Problem says, in words, what is wrong and what to do; empty when nothing is."
+          }
+        }
+      },
       "Live": {
         "type": "object",
         "description": "Live is one of the cluster's adapters as its node last reported it.",
@@ -5696,6 +5772,13 @@
           "control_planes": {
             "$ref": "#/components/schemas/ControlPlanes",
             "description": "ControlPlanes is the cluster's control planes when there is more than one: which leads, which stand by, and the floating address in front."
+          },
+          "judges": {
+            "type": "array",
+            "items": {
+              "$ref": "#/components/schemas/JudgeView"
+            },
+            "description": "Judges are the guardrails' judge models with something wrong."
           }
         }
       },

docs/guardrails.md

@@ -103,7 +103,23 @@ guard:
 
 Patterns find what has a shape. For what does not — violence, self-harm,
 abuse, whatever a moderation model was trained on — a policy can have a
-**judge model on the cluster** read the text:
+**judge model on the cluster** read the text.
+
+The judge must be in the catalog under the name the policy gives, as a
+judge (`role: guard`), with a replica ready. When it is not, what the
+policy judges is refused with `guard_unavailable` (`fail: closed`) or served
+unjudged (`fail: open`), and `llmgw ctl status` and the console's Overview
+say which judge and why. To serve it:
+
+```
+llmgw ctl guard judge status           # each judge the policies ask, and what is wrong with it
+llmgw ctl guard judge enable           # Llama Guard 3 1B on CPUs, under the name the policies ask
+llmgw ctl guard judge enable --replace # when a model of that name is there, but not as a judge
+```
+
+or **Do → Serve the guardrails' judge** in the console. A Llama Guard file
+served from the mirror page is served as a judge too, under the name the
+policies ask. By hand, the catalog entry is:
 
 ```yaml
 # a catalog model (server.yaml models:, or ctl model add)

internal/cli/ctl.go

@@ -116,6 +116,13 @@ func (c *ctlClient) do(ctx context.Context, method, path string, body, out any)
 	if out == nil {
 		return nil
 	}
+	// An older control plane answers a path it does not know with its
+	// dashboard: a page, which read as JSON said only "invalid character '<'".
+	if strings.HasPrefix(resp.Header.Get("Content-Type"), "text/html") {
+		return fmt.Errorf("%s %s answered with a page, not the API: the control plane answering "+
+			"(the leader, through a standby) does not know it — is it on an older release? "+
+			"llmgw ctl status says which it runs", method, path)
+	}
 	return json.NewDecoder(resp.Body).Decode(out)
 }
 

internal/cli/ctl_config_test.go

@@ -0,0 +1,22 @@
+package cli
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+)
+
+func TestAPageInsteadOfTheAPIIsSaidPlainly(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		w.Header().Set("Content-Type", "text/html; charset=utf-8")
+		_, _ = w.Write([]byte("<!doctype html><title>llmgw</title>"))
+	}))
+	defer srv.Close()
+	c := newCtlClient(strings.TrimPrefix(srv.URL, "http://"), "")
+	var out map[string]any
+	err := c.get(t.Context(), "/api/v1/settings", &out)
+	if err == nil || !strings.Contains(err.Error(), "older release") || strings.Contains(err.Error(), "invalid character") {
+		t.Errorf("%v", err)
+	}
+}

internal/cli/guard.go

@@ -24,6 +24,7 @@ func newGuardCmd(client func() *ctlClient, asJSON *bool) *cobra.Command {
 			"Targets are written org:Acme, team:Acme/ml, project:Acme/ml/training (or\n" +
 			"with IDs), key:KEY-ID or user:USER-ID. An attachment applies at once.",
 	}
+	c.AddCommand(newGuardJudgeCmd(client, asJSON))
 	c.AddCommand(&cobra.Command{
 		Use:   "list",
 		Short: "The policies, and where each is attached",

internal/cli/guard_judge.go

@@ -0,0 +1,189 @@
+package cli
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"strings"
+	"time"
+
+	"github.com/spf13/cobra"
+
+	"gitea.mynodes.xyz/ilker/llmgw/internal/control/adminapi"
+	"gitea.mynodes.xyz/ilker/llmgw/internal/control/modelserve"
+)
+
+// The judge the guardrails are installed with: Meta's Llama Guard 3 1B,
+// from the repository server init fetches it from.
+const (
+	guardModelRepo = "QuantFactory/Llama-Guard-3-1B-GGUF"
+	guardModelFile = "Llama-Guard-3-1B.Q4_K_M.gguf"
+)
+
+func newGuardJudgeCmd(client func() *ctlClient, asJSON *bool) *cobra.Command {
+	c := &cobra.Command{
+		Use:   "judge",
+		Short: "The judge models the policies ask: whether each can answer, and serving one",
+		Long: "A policy with a judge has a model read what patterns cannot. The judge must\n" +
+			"be in the catalog under the name the policy gives, as a judge (role:\n" +
+			"guard), with a replica ready; otherwise what the policy judges is refused\n" +
+			"(fail: closed, guard_unavailable) or served unjudged (fail: open).",
+	}
+	c.AddCommand(newGuardJudgeStatusCmd(client, asJSON), newGuardJudgeEnableCmd(client))
+	return c
+}
+
+func newGuardJudgeStatusCmd(client func() *ctlClient, asJSON *bool) *cobra.Command {
+	return &cobra.Command{
+		Use:   "status",
+		Short: "Each judge the policies ask, and what is wrong with it",
+		Args:  cobra.NoArgs,
+		RunE: func(cmd *cobra.Command, _ []string) error {
+			var js []adminapi.JudgeView
+			if err := client().get(cmd.Context(), "/api/v1/guard/judges", &js); err != nil {
+				return err
+			}
+			if *asJSON {
+				return emitJSON(js)
+			}
+			out := cmd.OutOrStdout()
+			if len(js) == 0 {
+				fmt.Fprintln(out, "no policy asks a judge")
+				return nil
+			}
+			w := tabTo(out)
+			fmt.Fprintln(w, "JUDGE\tPOLICIES\tIN CATALOG\tAS JUDGE\tREADY\tSTATE")
+			for _, j := range js {
+				state := "answering"
+				if j.Problem != "" {
+					state = j.Problem
+				}
+				fmt.Fprintf(w, "%s\t%s\t%s\t%s\t%d/%d\t%s\n", j.Model, strings.Join(j.Policies, ","),
+					yesNo(j.InCatalog), yesNo(j.Judge), j.Ready, j.Wanted, state)
+			}
+			if err := w.Flush(); err != nil {
+				return err
+			}
+			strays, _ := strayJudges(cmd, client, js)
+			for _, s := range strays {
+				fmt.Fprintf(out, "\n%s looks like a judge's weights but is served as a model clients use, and no "+
+					"policy asks it: llmgw ctl model remove %s\n", s, s)
+			}
+			return nil
+		},
+	}
+}
+
+// strayJudges are models whose weights are a judge's but which are in the
+// catalog as models clients use, under a name no policy asks: what serving
+// Llama Guard from the mirror page did before it knew better.
+func strayJudges(cmd *cobra.Command, client func() *ctlClient, js []adminapi.JudgeView) ([]string, error) {
+	var models []adminapi.ModelView
+	if err := client().get(cmd.Context(), "/api/v1/models", &models); err != nil {
+		return nil, err
+	}
+	asked := map[string]bool{}
+	for _, j := range js {
+		asked[j.Model] = true
+	}
+	var out []string
+	for _, m := range models {
+		if !asked[m.Name] && strings.Contains(strings.ToLower(m.Source), "llama-guard") {
+			out = append(out, m.Name)
+		}
+	}
+	return out, nil
+}
+
+func newGuardJudgeEnableCmd(client func() *ctlClient) *cobra.Command {
+	var (
+		model, repo, file string
+		replicas, cores   int
+		replace, detach   bool
+	)
+	c := &cobra.Command{
+		Use:   "enable",
+		Short: "Serve the judge the policies ask, as a judge: Llama Guard 3 1B on CPUs",
+		Long: "Fetches Llama Guard 3 1B into the mirror (once), adds it to the catalog under\n" +
+			"the name the policies give its judge, as a judge (role: guard,\n" +
+			"format llamaguard3), on CPUs so it takes no card, and waits for a replica\n" +
+			"to answer. With no --model, the judge the policies ask that is missing.\n\n" +
+			"A model of that name already in the catalog as a model clients use is\n" +
+			"refused; --replace removes it first. An offline cluster gets its judge\n" +
+			"from its bundle with server init.",
+		Example: "  llmgw ctl guard judge enable\n" +
+			"  llmgw ctl guard judge enable --replace",
+		Args: cobra.NoArgs,
+		RunE: func(cmd *cobra.Command, _ []string) error {
+			ctx := cmd.Context()
+			out := cmd.OutOrStdout()
+			var js []adminapi.JudgeView
+			if err := client().get(ctx, "/api/v1/guard/judges", &js); err != nil {
+				return err
+			}
+			var target *adminapi.JudgeView
+			for i, j := range js {
+				if (model != "" && j.Model == model) || (model == "" && (!j.InCatalog || !j.Judge)) {
+					target = &js[i]
+					break
+				}
+			}
+			switch {
+			case target == nil && model != "":
+				target = &adminapi.JudgeView{Model: model}
+				fmt.Fprintf(out, "no policy asks %s yet; it is served, and a policy's judge.model names it\n", model)
+			case target == nil && len(js) == 0:
+				return errors.New("no policy asks a judge: give one a judge (llmgw ctl config edit, guard.policies.<name>.judge.model)")
+			case target == nil:
+				fmt.Fprintln(out, "every judge the policies ask is in the catalog, as a judge")
+				return nil
+			}
+			if target.InCatalog && target.Judge {
+				fmt.Fprintf(out, "%s is in the catalog as a judge already; llmgw ctl guard judge status says how it is\n", target.Model)
+				return nil
+			}
+			if target.InCatalog && !target.Judge {
+				if !replace {
+					return fmt.Errorf("%s is in the catalog as a model clients use, not as a judge: "+
+						"--replace removes it and serves it again as a judge", target.Model)
+				}
+				var res map[string]string
+				if err := client().delete(ctx, "/api/v1/models/"+target.Model, &res); err != nil {
+					return fmt.Errorf("removing %s: %w", target.Model, err)
+				}
+				fmt.Fprintf(out, "%s removed\n", target.Model)
+			}
+			req := modelserve.Request{
+				Repo: repo, File: file, Name: target.Model, GuardFormat: "llamaguard3",
+				Description: "The guardrails' judge: reads prompts and answers for unsafe content. Not offered to clients.",
+				CPU:         true, Replicas: replicas, CPUCores: cores,
+				CtxPool: 8192, ContextLength: 4096,
+			}
+			body, _ := json.Marshal(req)
+			var job modelserve.Job
+			if err := client().patient(30*time.Second).post(ctx, "/api/v1/models/serve", body, &job); err != nil {
+				return err
+			}
+			if detach {
+				return detached(cmd, job)
+			}
+			if err := followJob(cmd, client, job, "is the judge"); err != nil {
+				return err
+			}
+			if strays, _ := strayJudges(cmd, client, js); len(strays) > 0 {
+				fmt.Fprintf(out, "\nno policy asks %s, served from a judge's weights as a model clients use: "+
+					"llmgw ctl model remove %s\n", strings.Join(strays, ", "), strings.Join(strays, " "))
+			}
+			return nil
+		},
+	}
+	f := c.Flags()
+	f.StringVar(&model, "model", "", "the judge to serve (default: the one the policies ask that is missing)")
+	f.StringVar(&repo, "repo", guardModelRepo, "the registry repository its weights come from")
+	f.StringVar(&file, "file", guardModelFile, "the file in it")
+	f.IntVar(&replicas, "replicas", 2, "replicas: every judged request waits on one")
+	f.IntVar(&cores, "cores", 4, "CPU cores a replica computes on")
+	f.BoolVar(&replace, "replace", false, "remove a model of that name that is not a judge first")
+	f.BoolVar(&detach, "detach", false, "start it and return; llmgw ctl jobs follows it")
+	return c
+}

internal/cli/server.go

@@ -361,7 +361,8 @@ func newServerCmd() *cobra.Command {
 				evals = newEvalService(cfg, rt, admin, log)
 				api.SetEval(evals)
 				if st := rt.Store(); st != nil && gate != nil {
-					api.SetGuard(&adminapi.GuardAdmin{Library: gate.Library, Store: st, Invalidate: gate.Invalidate})
+					api.SetGuard(&adminapi.GuardAdmin{Library: gate.Library, Store: st, Invalidate: gate.Invalidate,
+						JudgeErrors: gate.JudgeErrors})
 				}
 				if st := rt.Store(); st != nil {
 					// Removing a node revokes its certificate.

internal/cli/status.go

@@ -153,6 +153,13 @@ func printSummary(cmd *cobra.Command, s adminapi.Summary) {
 		fmt.Fprintf(out, "STORE     %s\n", strings.Join(parts, ", "))
 	}
 
+	if len(s.Judges) > 0 {
+		fmt.Fprintln(out, "\nGUARDRAILS' JUDGE")
+		for _, j := range s.Judges {
+			fmt.Fprintf(out, "  %s: %s\n", j.Model, j.Problem)
+		}
+	}
+
 	if len(s.Parked) > 0 {
 		fmt.Fprintln(out, "\nPARKED — failed every time they started; not retried until fixed")
 		for _, p := range s.Parked {

internal/cli/tui_actions.go

@@ -679,6 +679,8 @@ func (m *consoleModel) doEntry() tea.Cmd {
 			}}
 	case cBackup:
 		return m.runAfter("server", "backup", "--config="+m.file)
+	case cJudge:
+		return m.runAfter("ctl", server, "guard", "judge", "enable", "--replace")
 	}
 	return nil
 }

internal/cli/tui_console.go

@@ -59,6 +59,7 @@ const (
 	cAddControl
 	cReplicate
 	cServe
+	cJudge
 	cUpgrade
 	cRestartAll
 	cBackup
@@ -68,7 +69,7 @@ const (
 )
 
 var consoleLabels = [cCount]string{"Overview", "Monitor", "Nodes", "GPUs", "Models", "Replicas", "Usage", "Quotas", "Guardrails", "Federation", "Mirror", "Jobs", "Logs", "Accounts", "API keys", "Organizations", "Audit", "Manual",
-	"server.yaml", "Add a node", "Add a control plane", "Replicate the store", "Serve a model", "Upgrade the cluster",
+	"server.yaml", "Add a node", "Add a control plane", "Replicate the store", "Serve a model", "Serve the guardrails' judge", "Upgrade the cluster",
 	"Restart all replicas", "Back up now", "Wipe this machine", "Leave"}
 
 // consoleAction is what is done once the screen closes: each runs its own
@@ -496,7 +497,7 @@ func (m consoleModel) key(k tea.KeyMsg) (tea.Model, tea.Cmd) {
 				return m.leave()
 			case cWipe:
 				return m.askWipe()
-			case cUpgrade, cRestartAll, cBackup:
+			case cUpgrade, cRestartAll, cBackup, cJudge:
 				return m, m.doEntry()
 			case cOverview:
 				return m, nil
@@ -1299,6 +1300,9 @@ func (m consoleModel) panel() (title, body, keys string) {
 		item = "\n  Moves the store onto two machines under Patroni, replicated,\n  so losing one loses nothing.\n\n  " +
 			sDim.Render("On the command line:") +
 			"\n  sudo --preserve-env=SSH_AUTH_SOCK llmgw server init \\\n    --patroni <user>@<a> --patroni <user>@<b> --no-mirror --no-node --no-model"
+	case cJudge:
+		item = "\n  Serves the model the guardrail policies ask as their judge — Llama\n  Guard 3 1B on CPUs, under the name the policies give it — so what they\n  judge is not refused (guard_unavailable). A model of that name that is\n  not a judge is replaced. Overview says when a judge is missing.\n\n  " +
+			sDim.Render("On the command line:") + "\n  llmgw ctl guard judge status\n  llmgw ctl guard judge enable --replace"
 	case cUpgrade:
 		item = "\n  Moves the cluster to a release: this machine first, then each node\n  in turn. Engines keep serving; a node that does not come back stops it.\n\n  " +
 			sDim.Render("On the command line:") + "\n  sudo llmgw ctl upgrade VERSION"

internal/control/adminapi/guard.go

@@ -28,6 +28,8 @@ type GuardAdmin struct {
 	Library    func() guard.Config
 	Store      GuardStore
 	Invalidate func()
+	// JudgeErrors are each judge's last failure to give a verdict.
+	JudgeErrors func() map[string]guard.JudgeError
 }
 
 // SetGuard enables the guard endpoints.
@@ -198,6 +200,7 @@ type GuardAttachmentRequest struct {
 }
 
 func (a *API) registerGuard(mux Mux) {
+	mux.HandleFunc("GET /api/v1/guard/judges", a.listJudges)
 	mux.HandleFunc("GET /api/v1/guard", func(w http.ResponseWriter, r *http.Request) {
 		if a.guard == nil {
 			writeError(w, http.StatusNotImplemented, "no guard policies: define them under guard in the cluster's settings (llmgw ctl config edit)")

internal/control/adminapi/judges.go

@@ -0,0 +1,124 @@
+package adminapi
+
+import (
+	"fmt"
+	"net/http"
+	"slices"
+	"sort"
+	"time"
+
+	"gitea.mynodes.xyz/ilker/llmgw/internal/control/reconciler"
+	"gitea.mynodes.xyz/ilker/llmgw/internal/guard"
+)
+
+// JudgeView is one judge model the guardrail policies ask, and whether it
+// can answer them.
+type JudgeView struct {
+	Model string `json:"model"`
+	// Policies are those that ask it; Closed those that refuse what it
+	// cannot read (fail: closed).
+	Policies []string `json:"policies"`
+	Closed   []string `json:"closed,omitempty"`
+	// InCatalog is whether a model of that name is in the catalog, and
+	// Judge whether it is there as a judge (role: guard).
+	InCatalog bool `json:"in_catalog"`
+	Judge     bool `json:"judge"`
+	Ready     int  `json:"ready_replicas"`
+	Wanted    int  `json:"wanted_replicas"`
+	// LastError is its last failure to give a verdict, if any.
+	LastError   string     `json:"last_error,omitempty"`
+	LastErrorAt *time.Time `json:"last_error_at,omitempty"`
+	// Problem says, in words, what is wrong and what to do; empty when
+	// nothing is.
+	Problem string `json:"problem,omitempty"`
+}
+
+// judgeErrorFresh is how recent a judge's failure must be to count as a
+// problem now.
+const judgeErrorFresh = 5 * time.Minute
+
+// Judges are the judge models the policies in force ask, each with what is
+// wrong with it, if anything.
+func (a *API) Judges() []JudgeView {
+	if a.guard == nil || a.guard.Library == nil {
+		return nil
+	}
+	lib := a.guard.Library()
+	byModel := map[string]*JudgeView{}
+	for name, p := range lib.Policies {
+		if p.Judge == nil || p.Judge.Model == "" {
+			continue
+		}
+		v := byModel[p.Judge.Model]
+		if v == nil {
+			v = &JudgeView{Model: p.Judge.Model}
+			byModel[p.Judge.Model] = v
+		}
+		v.Policies = append(v.Policies, name)
+		if p.Fail == "closed" && p.Mode != "shadow" {
+			v.Closed = append(v.Closed, name)
+		}
+	}
+	ready := map[string]int{}
+	for _, rep := range a.ctl.Reconciler().Replicas() {
+		if rep.State == reconciler.Ready {
+			ready[rep.Model]++
+		}
+	}
+	var errs map[string]guard.JudgeError
+	if a.guard.JudgeErrors != nil {
+		errs = a.guard.JudgeErrors()
+	}
+	out := make([]JudgeView, 0, len(byModel))
+	for _, v := range byModel {
+		sort.Strings(v.Policies)
+		sort.Strings(v.Closed)
+		if m, ok := a.ctl.Catalog().Resolve(v.Model); ok && m.Name == v.Model {
+			v.InCatalog, v.Judge = true, m.IsGuard()
+			v.Wanted, v.Ready = m.Scaling.Min, ready[m.Name]
+		}
+		if e, ok := errs[v.Model]; ok {
+			at := e.At
+			v.LastError, v.LastErrorAt = e.Err, &at
+		}
+		v.Problem = judgeProblem(*v)
+		out = append(out, *v)
+	}
+	slices.SortFunc(out, func(x, y JudgeView) int {
+		switch {
+		case x.Model < y.Model:
+			return -1
+		case x.Model > y.Model:
+			return 1
+		}
+		return 0
+	})
+	return out
+}
+
+func judgeProblem(v JudgeView) string {
+	consequence := "requests its policies judge are served unjudged"
+	if len(v.Closed) > 0 {
+		consequence = "requests its policies judge are refused (guard_unavailable)"
+	}
+	switch {
+	case !v.InCatalog:
+		return fmt.Sprintf("not in the catalog, so %s: llmgw ctl guard judge enable", consequence)
+	case !v.Judge:
+		return fmt.Sprintf("in the catalog as a model clients use, not as a judge (role: guard), so %s: "+
+			"llmgw ctl guard judge enable --replace", consequence)
+	case v.Ready == 0:
+		return fmt.Sprintf("no replica ready, so %s: llmgw ctl replicas --model %s", consequence, v.Model)
+	case v.LastErrorAt != nil && time.Since(*v.LastErrorAt) < judgeErrorFresh:
+		return fmt.Sprintf("gave no verdict %s ago (%s)", time.Since(*v.LastErrorAt).Round(time.Second), v.LastError)
+	}
+	return ""
+}
+
+func (a *API) listJudges(w http.ResponseWriter, _ *http.Request) {
+	if a.guard == nil {
+		writeError(w, http.StatusNotImplemented, "no guard policies: define them under guard in the cluster's settings (llmgw ctl config edit)")
+		return
+	}
+	writeJSON(w, http.StatusOK, a.Judges())
+}

internal/control/adminapi/judges_test.go

@@ -0,0 +1,66 @@
+package adminapi
+
+import (
+	"strings"
+	"testing"
+	"time"
+
+	"gitea.mynodes.xyz/ilker/llmgw/internal/control/catalog"
+	"gitea.mynodes.xyz/ilker/llmgw/internal/guard"
+)
+
+func TestEachJudgeSaysWhatIsWrongWithIt(t *testing.T) {
+	models := append(testModels(),
+		// Served from the mirror page before it knew better: a model
+		// clients use, under the judge's name.
+		catalog.Model{Name: "shield", Source: "/s", Scaling: catalog.Scaling{Min: 1, Max: 1},
+			Profiles: []catalog.Profile{{Name: "cpu", Engine: "llamacpp"}}},
+		catalog.Model{Name: "llama-guard-3-1b", Source: "/g", Role: catalog.RoleGuard,
+			Guard: &catalog.GuardModel{Format: "llamaguard3"}, Scaling: catalog.Scaling{Min: 2, Max: 2},
+			Profiles: []catalog.Profile{{Name: "cpu", Engine: "llamacpp"}}})
+	a, _ := setup(t, models)
+	lib := guard.Config{Default: []string{"baseline"}, Policies: map[string]guard.Policy{
+		"baseline": {Fail: "closed", Judge: &guard.JudgePolicy{Model: "llama-guard-3-1b", Input: "block"}},
+		"strict":   {Fail: "closed", Judge: &guard.JudgePolicy{Model: "missing-judge", Input: "block"}},
+		"shield":   {Fail: "open", Judge: &guard.JudgePolicy{Model: "shield", Input: "flag"}},
+	}}
+	a.SetGuard(&GuardAdmin{Library: func() guard.Config { return lib }})
+
+	var js []JudgeView
+	if code := call(t, a, "GET", "/api/v1/guard/judges", "", &js); code != 200 || len(js) != 3 {
+		t.Fatalf("%d %+v", code, js)
+	}
+	by := map[string]JudgeView{}
+	for _, j := range js {
+		by[j.Model] = j
+	}
+	if j := by["missing-judge"]; j.InCatalog || !strings.Contains(j.Problem, "not in the catalog") ||
+		!strings.Contains(j.Problem, "refused") {
+		t.Errorf("missing: %+v", j)
+	}
+	if j := by["shield"]; !j.InCatalog || j.Judge || !strings.Contains(j.Problem, "--replace") ||
+		!strings.Contains(j.Problem, "unjudged") {
+		t.Errorf("not a judge: %+v", j)
+	}
+	if j := by["llama-guard-3-1b"]; !j.Judge || j.Wanted != 2 || !strings.Contains(j.Problem, "no replica ready") {
+		t.Errorf("not running: %+v", j)
+	}
+
+	var s Summary
+	call(t, a, "GET", "/api/v1/summary", "", &s)
+	if len(s.Judges) != 3 {
+		t.Errorf("the summary does not carry the judges' problems: %+v", s.Judges)
+	}
+
+	// A judge that failed lately says so, once it is otherwise fine.
+	at := time.Now()
+	v := JudgeView{Model: "x", InCatalog: true, Judge: true, Ready: 1, LastError: "deadline exceeded", LastErrorAt: &at}
+	if p := judgeProblem(v); !strings.Contains(p, "deadline exceeded") {
+		t.Errorf("a recent failure: %q", p)
+	}
+	old := at.Add(-time.Hour)
+	v.LastErrorAt = &old
+	if p := judgeProblem(v); p != "" {
+		t.Errorf("an old failure still counts: %q", p)
+	}
+}

internal/control/adminapi/routes.go

@@ -254,6 +254,8 @@ var Routes = []Route{
 			{Name: "since", Description: "How far back: 90m, 24h, 7d; 24h when absent."},
 		},
 		Response: GuardEventsView{}},
+	{Method: "GET", Path: "/api/v1/guard/judges", Summary: "The judge models the policies ask, and what is wrong with each",
+		Response: []JudgeView{}},
 	{Method: "POST", Path: "/api/v1/guard/attachments", Summary: "Attach a guardrail policy",
 		Request: GuardAttachmentRequest{}, Response: guard.Attachment{}},
 	{Method: "DELETE", Path: "/api/v1/guard/attachments", Summary: "Detach a guardrail policy",

internal/control/adminapi/summary.go

@@ -42,6 +42,8 @@ type Summary struct {
 	// ControlPlanes is the cluster's control planes when there is more than
 	// one: which leads, which stand by, and the floating address in front.
 	ControlPlanes ControlPlanes `json:"control_planes,omitzero"`
+	// Judges are the guardrails' judge models with something wrong.
+	Judges []JudgeView `json:"judges,omitempty"`
 }
 
 // StoreMember is one member of a replicated store, as its Patroni reports it.
@@ -149,6 +151,11 @@ const idleThreshold = 10 * time.Minute
 // Summary builds the fleet summary.
 func (a *API) Summary() Summary {
 	s := Summary{Version: version.Version}
+	for _, j := range a.Judges() {
+		if j.Problem != "" {
+			s.Judges = append(s.Judges, j)
+		}
+	}
 	if a.storeStatus != nil {
 		members, err := a.storeStatus()
 		s.Store = members

internal/guard/gate.go

@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"log/slog"
+	"maps"
 	"regexp"
 	"sort"
 	"strings"
@@ -43,6 +44,9 @@ type Gate struct {
 	m      *gateMetrics
 	// alarm is told each time a judge gives no verdict; nil tells no one.
 	alarm func(model string, err error)
+	// lastErr is each judge's last failure to give a verdict.
+	errMu   sync.Mutex
+	lastErr map[string]JudgeError
 
 	mu       sync.Mutex
 	attached map[string][]string // "scope/id" → policy names
@@ -448,11 +452,30 @@ func (g *Gate) Input(ctx context.Context, s Subject, body []byte) (Verdict, erro
 func (g *Gate) SetJudgeAlarm(f func(model string, err error)) { g.alarm = f }
 
 func (g *Gate) judgeFailed(model string, err error) {
+	g.errMu.Lock()
+	if g.lastErr == nil {
+		g.lastErr = map[string]JudgeError{}
+	}
+	g.lastErr[model] = JudgeError{Err: err.Error(), At: g.now()}
+	g.errMu.Unlock()
 	if g.alarm != nil {
 		g.alarm(model, err)
 	}
 }
 
+// JudgeError is a judge's last failure to give a verdict.
+type JudgeError struct {
+	Err string
+	At  time.Time
+}
+
+// JudgeErrors are each judge's last failure to give a verdict, by model.
+func (g *Gate) JudgeErrors() map[string]JudgeError {
+	g.errMu.Lock()
+	defer g.errMu.Unlock()
+	return maps.Clone(g.lastErr)
+}
+
 func judgeFinding(p Policy, action string, res judgment, err error) finding {
 	if err != nil {
 		// Unanswered: closed stops it, open lets it through, said.

internal/web/account.go

@@ -88,8 +88,10 @@ type AccountPages struct {
 	oidc *oidcLogin
 	// audit records every change made through these pages; nil records none.
 	audit audit.Sink
-	// hasGuard is set when /admin/guard is registered.
-	hasGuard bool
+	// hasGuard is set when /admin/guard is registered, and guardLibrary
+	// with it: the policies in force, whose judges the mirror page serves.
+	hasGuard     bool
+	guardLibrary func() guard.Config
 	// guardFor names the guardrail policies in force for someone, and
 	// whether they keep nothing; nil when there are none.
 	guardFor func(guard.Subject) (string, bool)

internal/web/admin_guard.go

@@ -50,7 +50,7 @@ var guardWindows = map[string]time.Duration{"24h": 24 * time.Hour, "7d": 7 * 24
 // RegisterAdminGuard mounts /admin/guard: what the guardrails did, where, by
 // which policy — names and counts, never text.
 func (p *AccountPages) RegisterAdminGuard(mux *http.ServeMux, s GuardAdminSource, library func() guard.Config) {
-	p.hasGuard = true
+	p.hasGuard, p.guardLibrary = true, library
 	mux.HandleFunc("GET /admin/guard", p.adminOnly(func(w http.ResponseWriter, r *http.Request, admin store.User) {
 		ctx, l := r.Context(), langOf(r)
 		lib := library()

internal/web/admin_mirror.go

@@ -324,10 +324,14 @@ func (p *AccountPages) RegisterAdminMirror(mux *http.ServeMux, d MirrorDeps) {
 				if err != nil {
 					return "", err
 				}
+				// A judge's weights are served as a judge, under the name the
+				// policies ask: served as a model clients use, the policies
+				// never find it and refuse every request they judge.
+				judge, renamed := p.asJudge(&model)
 				// The CPU while GPUs sit free is a choice to make on purpose:
 				// made by default, it was a model running at a tenth of the
-				// speed with nothing saying why.
-				if model.Profiles[0].CPUOnly() && r.FormValue("cpu_ok") == "" {
+				// speed with nothing saying why. A judge is meant for the CPU.
+				if !judge && model.Profiles[0].CPUOnly() && r.FormValue("cpu_ok") == "" {
 					if n := freeGPUs(p.fleet); n > 0 {
 						return "", errors.New(l.N("serve.err.cpu_with_free_gpus", int64(n), model.Name))
 					}
@@ -346,8 +350,15 @@ func (p *AccountPages) RegisterAdminMirror(mux *http.ServeMux, d MirrorDeps) {
 				}
 				// Placed on the next pass, not now: saying it is serving would
 				// be wrong for however long the weights take to reach a node.
-				return l.T("serve.msg.added", model.Name,
-					l.N("serve.replicas_n", int64(model.Scaling.Min)), describeServe(l, model)), nil
+				msg := l.T("serve.msg.added", model.Name,
+					l.N("serve.replicas_n", int64(model.Scaling.Min)), describeServe(l, model))
+				switch {
+				case renamed != "":
+					msg += " " + l.T("serve.msg.judge_renamed", renamed, model.Name)
+				case judge:
+					msg += " " + l.T("serve.msg.judge", model.Name)
+				}
+				return msg, nil
 			}))
 	}
 

internal/web/admin_mirror_test.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"gitea.mynodes.xyz/ilker/llmgw/internal/control/catalog"
+	"gitea.mynodes.xyz/ilker/llmgw/internal/guard"
 	"io"
 	"log/slog"
 	"net/http"
@@ -745,3 +746,23 @@ func TestASafetensorsSetIsFetchedWithWhatTheEngineReadsBesideIt(t *testing.T) {
 		t.Errorf("the companions are not said; got %s", body)
 	}
 }
+
+func TestAJudgesWeightsAreServedAsTheJudgeThePoliciesAsk(t *testing.T) {
+	p := &AccountPages{guardLibrary: func() guard.Config {
+		return guard.Config{Policies: map[string]guard.Policy{
+			"baseline": {Judge: &guard.JudgePolicy{Model: "llama-guard-3-1b"}},
+		}}
+	}}
+	m := catalog.Model{Name: "llama-guard", Source: "http://10.0.0.146:8081/llama-guard/x/Llama-Guard-3-1B.Q4_K_M.gguf",
+		RoutingProfile: "chat"}
+	judge, renamed := p.asJudge(&m)
+	if !judge || renamed != "llama-guard" || m.Name != "llama-guard-3-1b" || !m.IsGuard() ||
+		m.Guard.Format != "llamaguard3" || m.RoutingProfile != "" {
+		t.Errorf("judge %v renamed %q: %+v", judge, renamed, m)
+	}
+
+	plain := catalog.Model{Name: "qwen", Source: "http://m/qwen.gguf", RoutingProfile: "chat"}
+	if judge, _ := p.asJudge(&plain); judge || plain.IsGuard() || plain.Name != "qwen" {
+		t.Errorf("a model clients use became a judge: %+v", plain)
+	}
+}

internal/web/admin_serve.go

@@ -585,3 +585,36 @@ func argInt(args []string, flag string) int {
 	}
 	return 0
 }
+
+// isJudgeWeights is whether a source is a guard model's weights: Llama
+// Guard, which reads a conversation and says whether it is safe.
+func isJudgeWeights(source string) bool {
+	return strings.Contains(strings.ToLower(source), "llama-guard")
+}
+
+// asJudge makes a model built from the serve form a judge when its weights
+// are one's: role guard, Llama Guard's format, under the name the policies
+// give their judge when they give one and the form gave another. It says
+// whether it did, and the name the form gave when it was changed.
+func (p *AccountPages) asJudge(m *catalog.Model) (judge bool, renamed string) {
+	if !isJudgeWeights(m.Source) {
+		return false, ""
+	}
+	m.Role, m.Guard, m.RoutingProfile = catalog.RoleGuard, &catalog.GuardModel{Format: "llamaguard3"}, ""
+	if p.guardLibrary == nil {
+		return true, ""
+	}
+	asked := map[string]bool{}
+	for _, pol := range p.guardLibrary().Policies {
+		if pol.Judge != nil && pol.Judge.Model != "" {
+			asked[pol.Judge.Model] = true
+		}
+	}
+	if asked[m.Name] || len(asked) != 1 {
+		return true, ""
+	}
+	for name := range asked {
+		renamed, m.Name = m.Name, name
+	}
+	return true, renamed
+}

internal/web/locales/en/serve.json

@@ -77,5 +77,7 @@
   "serve.err.cpu_with_free_gpus.other": "this fleet has %d GPUs free and %s was set to run on the CPU; choose a GPU placement, or tick \"run on the CPU anyway\"",
   "serve.msg.added": "%s added to the catalog, %s: %s; it is placed on the next pass",
   "serve.replicas_n.one": "%d replica",
-  "serve.replicas_n.other": "%d replicas"
+  "serve.replicas_n.other": "%d replicas",
+  "serve.msg.judge": "It is the guardrails' judge (role: guard): policies naming %s ask it; clients do not see it.",
+  "serve.msg.judge_renamed": "Its weights are a judge's, so it is the guardrails' judge (role: guard), named %[2]s as the policies ask rather than %[1]s."
 }

internal/web/locales/tr/serve.json

@@ -74,5 +74,7 @@
   "serve.err.placement": "%q geçerli bir yerleşim değil",
   "serve.err.cpu_with_free_gpus.other": "bu kümede %d GPU boşta, %s ise CPU üzerinde çalışacak biçimde ayarlandı; bir GPU yerleşimi seçin ya da \"yine de CPU üzerinde çalıştır\" kutusunu işaretleyin",
   "serve.msg.added": "%s kataloğa eklendi, %s: %s; bir sonraki geçişte yerleştirilecek",
-  "serve.replicas_n.other": "%d replika"
+  "serve.replicas_n.other": "%d replika",
+  "serve.msg.judge": "Guardrail'lerin judge modeli olarak eklendi (role: guard): %s adını veren politikalar ona soruyor; istemciler görmüyor.",
+  "serve.msg.judge_renamed": "Ağırlıkları bir judge modelinin olduğu için guardrail judge'ı olarak eklendi (role: guard); adı %[1]s yerine politikaların istediği gibi %[2]s."
 }