diff --git a/internal/gateway/session_route.go b/internal/gateway/session_route.go
index 4044c96f..ffd05cb7 100644
--- a/internal/gateway/session_route.go
+++ b/internal/gateway/session_route.go
@@ -129,7 +129,7 @@ func (t *trace) sessionLatest(ctx context.Context, session string, after int64,
 		for i := len(t.routes) - 1; i >= 0; i-- {
 			if r := t.routes[i]; r.Session == session {
 				c := *r
-				c.Order = append([]Weighed(nil), r.Order...)
+				c.Order = append([]Weighed{}, r.Order...) // [] for none: the GUI reads it as a list
 				c.Left = append([]Weighed(nil), r.Left...)
 				c.Tries = append([]Try{}, r.Tries...)
 				seq, found = r.Seq, &c
diff --git a/internal/gateway/trace.go b/internal/gateway/trace.go
index 98debba0..9e9bdc04 100644
--- a/internal/gateway/trace.go
+++ b/internal/gateway/trace.go
@@ -395,7 +395,7 @@ func (t *trace) update(r *Route, f func(r *Route)) {
 		}
 		if keepRoutes {
 			c := *r
-			c.Order = append([]Weighed(nil), r.Order...)
+			c.Order = append([]Weighed{}, r.Order...) // [] for none: the GUI reads it as a list
 			c.Left = append([]Weighed(nil), r.Left...)
 			c.Tries = append([]Try{}, r.Tries...)
 			c.Usage = append([]RouteUsage(nil), r.Usage...)
@@ -421,7 +421,7 @@ func (s *Server) Trace(ctx context.Context, after int64, wait time.Duration) Tra
 		for _, r := range t.routes {
 			if r.Seq > after {
 				c := *r
-				c.Order = append([]Weighed(nil), r.Order...)
+				c.Order = append([]Weighed{}, r.Order...) // [] for none: the GUI reads it as a list
 				c.Left = append([]Weighed(nil), r.Left...)
 				c.Tries = append([]Try{}, r.Tries...)
 				c.Usage = append([]RouteUsage(nil), r.Usage...)
diff --git a/internal/gateway/trace_test.go b/internal/gateway/trace_test.go
index 1ace6c55..e8d6b09c 100644
--- a/internal/gateway/trace_test.go
+++ b/internal/gateway/trace_test.go
@@ -2,6 +2,7 @@ package gateway
 
 import (
 	"context"
+	"encoding/json"
 	"io"
 	"net/http"
 	"net/http/httptest"
@@ -113,3 +114,26 @@ func TestRetryAfterRests(t *testing.T) {
 		t.Fatalf("rest %+v", r)
 	}
 }
+
+// A route weighed with no seats tells its order as [], not null: the
+// Routing page reads it as a list, and a null one left a refused request
+// that couldn't be opened (Discord, mythfish on v0.1.810).
+func TestTraceOrderIsAList(t *testing.T) {
+	s := New()
+	r := s.trace.begin(Route{Model: "workbuddy-ai/deepseek-v4.1-flash"})
+	s.trace.update(r, func(r *Route) {
+		r.Tries = append(r.Tries, Try{ID: "workbuddy-ai", Status: 400, Error: "WorkBuddy AI: Invalid request parameters"})
+		r.Status, r.Error, r.Done = 400, "WorkBuddy AI: Invalid request parameters", true
+	})
+	st := s.Trace(context.Background(), 0, 0)
+	b, err := json.Marshal(st.Routes)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !strings.Contains(string(b), `"order":[]`) || strings.Contains(string(b), `"order":null`) {
+		t.Fatalf("trace routes = %s, want order []", b)
+	}
+	if _, c := s.trace.sessionLatest(context.Background(), "", 0, 0); c == nil || c.Order == nil {
+		t.Fatalf("session's latest route = %+v, want a non-nil order", c)
+	}
+}
diff --git a/internal/gui/assets/routing.js b/internal/gui/assets/routing.js
index 44d1f346..df897e4d 100644
--- a/internal/gui/assets/routing.js
+++ b/internal/gui/assets/routing.js
@@ -777,6 +777,14 @@
   // tried is the seat a try went to
   const tried = (r, tr) => r.order.find((x) => seat(x) === seat(tr)) || r.order.find((x) => x.id === tr.id);
   const setOf = (r) => r.order.map(seat).sort().join("\n");
+  // whole fills in the lists a route's JSON can leave null: a route the
+  // gateway weighed no seats for has "order": null, and the page reads
+  // r.order, r.tries and r.left as lists everywhere — one null threw in
+  // pick, and clicking such a request (a refused one) opened nothing
+  const whole = (r) => {
+    if (r) { r.order ||= []; r.tries ||= []; r.left ||= []; }
+    return r;
+  };
 
   // staged: the routes the stage shows — a picked one alone; else those
   // playing, and each agent's latest while it lingers, a few agents at most
@@ -1168,7 +1176,7 @@
       const res = await fetch("/api/gateway/route?id=" + encodeURIComponent(id) + "&day=" + encodeURIComponent(time.slice(0, 10)));
       if (res.status === 404) throw new Error(t("Routing history for this request is no longer available."));
       if (!res.ok) throw new Error(await res.text());
-      r = await res.json();
+      r = whole(await res.json());
       noteAccounts(r);
     }
     day = routes.has(id) ? "" : r.time.slice(0, 10);
@@ -1277,7 +1285,7 @@
       const res = await (await fetch("/api/gateway/history?day=" + encodeURIComponent(d || ""))).json();
       days = res.days || [];
       noteAccounts(res.routes);
-      if (d && d === day) { past = res.routes || []; pastCut = !!res.cut; }
+      if (d && d === day) { past = (res.routes || []).map(whole); pastCut = !!res.cut; }
     } catch {}
     renderHist(); // shown once there are days, though none are live
   }
@@ -2096,7 +2104,7 @@
         const fresh = [];
         for (const r of d.routes) {
           if (!routes.has(r.id) && !first) fresh.push(r.id);
-          routes.set(r.id, r);
+          routes.set(r.id, whole(r));
         }
         for (const id of [...routes.keys()].sort((a, b) => a - b).slice(0, -60)) routes.delete(id);
         loaded = true;
diff --git a/internal/gui/tests/routing-failed-open.test.cjs b/internal/gui/tests/routing-failed-open.test.cjs
new file mode 100644
index 00000000..e4c17013
--- /dev/null
+++ b/internal/gui/tests/routing-failed-open.test.cjs
@@ -0,0 +1,100 @@
+// Run with Node's test runner and Playwright on the module path; see README.md.
+// A request the gateway weighed no seats for comes with "order": null (Go's
+// nil slice), and clicking it in the Routing page's list did nothing: pick
+// read r.order as a list and threw before the story was drawn (Discord,
+// mythfish on v0.1.810: "workbuddy-ai/deepseek-v4.1-flash • 400 · 失败 6.5 秒",
+// WorkBuddy AI: Invalid request parameters). Live and in a kept day, the
+// failed request opens and its story gives the vendor's words.
+const assert = require("node:assert/strict");
+const fs = require("node:fs/promises");
+const path = require("node:path");
+const { test } = require("node:test");
+const { chromium, webkit } = require("playwright");
+
+const assets = path.resolve(__dirname, "../assets");
+const now = new Date();
+const day = [now.getFullYear(), now.getMonth() + 1, now.getDate()].map((n) => String(n).padStart(2, "0")).join("-");
+const at = (i) => new Date(now.getTime() - (i + 1) * 60e3).toISOString();
+const vendor = "WorkBuddy AI: Invalid request parameters";
+const key = { id: "workbuddy-ai", provider: "workbuddy-ai", name: "WorkBuddy AI", kind: "provider", model: "deepseek-v4.1-flash" };
+const base = (i) => ({ id: 100 - i, seq: 100 - i, time: at(i), agent: "codex", model: "workbuddy-ai/deepseek-v4.1-flash", provider: "workbuddy-ai", done: true });
+// newest first: one that answered, then the 400 with no order, as the report's
+const routes = [
+  { ...base(0), order: [key], tries: [{ id: key.id, model: key.model, start: at(0), done: true, status: 200, ms: 900 }], status: 200, ms: 900 },
+  { ...base(1), order: null, tries: [{ id: key.id, model: key.model, start: at(1), done: true, status: 400, ms: 6500, error: vendor }], status: 400, ms: 6500, error: vendor },
+];
+
+function serve(lang, live) {
+  const state = { agents: [{ id: "codex", name: "Codex", path: "/test/config.toml", fields: [] }], profiles: [], settings: { lang, theme: "light" } };
+  return async (route) => {
+    const url = new URL(route.request().url());
+    const json = (data) => route.fulfill({ json: data });
+    if (url.pathname === "/boot.js") return route.fulfill({ contentType: "text/javascript", body: `window.bootPrefs = {lang:"${lang}",theme:"light",web:true};` });
+    if (url.pathname === "/wails/runtime.js") return route.fulfill({ contentType: "text/javascript", body: "export const Window = {};" });
+    if (url.pathname === "/api/state") return json(state);
+    if (url.pathname === "/api/plugins") return json({ plugins: [] });
+    if (url.pathname === "/api/gateway/trace") {
+      if (url.searchParams.get("wait")) await new Promise((r) => setTimeout(r, 20e3));
+      return json({ mine: true, now: now.toISOString(), seq: 1, totals: { requests: 0, rerouted: 0, errors: 0 }, routes: live ? structuredClone(routes) : [] });
+    }
+    if (url.pathname === "/api/gateway/history") {
+      const d = url.searchParams.get("day");
+      return json({ cut: false, days: live ? [] : [{ day, requests: routes.length }], routes: d && !live ? structuredClone(routes) : [] });
+    }
+    if (url.pathname === "/api/groups") return json({ groups: [] });
+    if (url.pathname === "/api/providers") return json({ providers: [], excluded: [], presets: [], gateway: { running: true, window: true } });
+    if (url.pathname.startsWith("/api/")) return json({});
+    const file = path.join(assets, url.pathname === "/" ? "index.html" : url.pathname);
+    const contentType = { ".html": "text/html", ".js": "text/javascript", ".css": "text/css", ".svg": "image/svg+xml", ".png": "image/png" }[path.extname(file)];
+    await route.fulfill({ body: await fs.readFile(file), contentType });
+  };
+}
+
+const want = {
+  en: { head: "How the request at", said: "It said: " + vendor },
+  zh: { head: "的请求是怎么路由的", said: "原话：" + vendor },
+};
+
+for (const engine of (process.env.BROWSER ? [process.env.BROWSER] : ["chromium", "webkit"])) {
+  for (const lang of ["en", "zh"]) {
+    for (const live of [true, false]) {
+      test(`${engine} ${lang} ${live ? "live" : "kept day"}: a failed request with no order opens`, async (t) => {
+        const browser = await (engine === "webkit" ? webkit.launch() : chromium.launch({ channel: "chromium" }));
+        const context = await browser.newContext({ viewport: { width: 1100, height: 760 }, reducedMotion: "reduce" });
+        const page = await context.newPage();
+        page.setDefaultTimeout(5000);
+        const errors = [];
+        page.on("pageerror", (e) => errors.push(e.message));
+        await page.route("**/*", serve(lang, live));
+        t.after(async () => {
+          if (process.env.ARTIFACT_DIR) {
+            await fs.mkdir(process.env.ARTIFACT_DIR, { recursive: true });
+            await page.screenshot({ path: path.join(process.env.ARTIFACT_DIR, `${engine}-${lang}-${live ? "live" : "day"}-failed-open.png`), fullPage: true });
+          }
+          await browser.close();
+        });
+        await page.goto("http://magpie.test/?view=routing");
+        if (!live) await page.locator(".rt-day").nth(1).click();
+        await page.locator(".rt-req").nth(routes.length - 1).waitFor();
+
+        const row = page.locator(".rt-req").nth(1);
+        assert.match(await row.textContent(), /400/);
+        const was = await row.evaluate((e) => e.getBoundingClientRect().top);
+        await row.click();
+        await page.waitForTimeout(400);
+        assert(Math.abs((await row.evaluate((e) => e.getBoundingClientRect().top)) - was) <= 1, "picking the request moved the page");
+        assert.equal(await row.getAttribute("aria-pressed"), "true");
+        assert(!(await page.locator(".rt-log").evaluate((e) => e.hidden)), "the story is hidden");
+        assert((await page.locator(".rt-log-head").textContent()).includes(want[lang].head));
+        const got = await page.locator(".rt-steps li").evaluateAll((ls) => ls.map((l) => [l.className, l.textContent]));
+        assert.deepEqual(got.filter(([c]) => c === "aside said").map(([, s]) => s), [want[lang].said], JSON.stringify(got));
+
+        // and back to the one that answered
+        await page.locator(".rt-req").nth(0).click();
+        await page.waitForTimeout(300);
+        assert.equal(await page.locator(".rt-req").nth(0).getAttribute("aria-pressed"), "true");
+        assert.deepEqual(errors, []);
+      });
+    }
+  }
+}