diff --git a/packages/chat-ui/src/api.ts b/packages/chat-ui/src/api.ts
index 2e7c5b21a..bb1f42b2f 100644
--- a/packages/chat-ui/src/api.ts
+++ b/packages/chat-ui/src/api.ts
@@ -15,6 +15,7 @@ import { parseParticipants } from "@corbits/chat/participants";
 import type { ParticipantRecord } from "@corbits/chat/participants";
 import type { WorkbenchOnboardingStep } from "@corbits/chat/blocks";
 import { UnauthenticatedError } from "@corbits/api-query";
+import { InferenceSettingsApiError } from "@corbits/inference-settings";
 import { jimmyAgentRequest } from "@workbench/templates";
 import { CHAT_STRINGS } from "./strings";
 
@@ -215,25 +216,38 @@ export class ChatApiError extends Error {
 /**
  * Plain-language copy for a failed chat request — never `error.message`
  * or `String(error)` verbatim, which for a `ChatApiError` embeds the raw
- * request path (see `request()` below). Every chat-ui/chat-adjacent
- * catch block that surfaces an error to the user should call this
- * rather than format one of its own, so the class of leak (a raw
- * `/api/...` URL or bare status code in user-facing copy) has exactly
- * one place to fix.
+ * request path (see `request()` below). `InferenceSettingsApiError`
+ * carries the envelope `userMessage` (safe to show) rather than a path,
+ * so a 500 from `getResolvedCatalog` surfaces that sentence instead of
+ * the generic fallback. Every chat-ui/chat-adjacent catch block that
+ * surfaces an error to the user should call this rather than format one
+ * of its own, so the class of leak (a raw `/api/...` URL or bare status
+ * code in user-facing copy) has exactly one place to fix.
  */
 export function describeChatError(cause: unknown, fallback: string): string {
-  if (!(cause instanceof ChatApiError)) return fallback;
-  switch (cause.status) {
+  const statused =
+    cause instanceof ChatApiError || cause instanceof InferenceSettingsApiError
+      ? cause
+      : null;
+  if (statused === null) return fallback;
+  switch (statused.status) {
     case 401:
       return "You're signed out. Sign in again to continue.";
     case 403:
       return "You don't have access to this.";
     case undefined:
       return "Couldn't reach the server. Check your connection and try again.";
-    default:
-      return cause.status >= 500
+    default: {
+      if (
+        cause instanceof InferenceSettingsApiError &&
+        statused.message.trim() !== ""
+      ) {
+        return statused.message;
+      }
+      return statused.status >= 500
         ? "Something went wrong on our end. Try again in a moment."
         : fallback;
+    }
   }
 }
 
diff --git a/packages/chat-ui/src/strings.ts b/packages/chat-ui/src/strings.ts
index 4a9790311..4017e1361 100644
--- a/packages/chat-ui/src/strings.ts
+++ b/packages/chat-ui/src/strings.ts
@@ -432,6 +432,9 @@ export const CHAT_STRINGS = {
   ) => `${canonicalName} · ${providerName}`,
   workbenchSettingsAgentDetailNoConnectedModels:
     "No connected providers yet — connect one in Shared Settings.",
+  workbenchSettingsAgentDetailCatalogError: "Couldn't load the models.",
+  workbenchSettingsAgentDetailCatalogRetryAction: "Retry",
+  workbenchSettingsAgentDetailCatalogSettingsAction: "Shared Settings",
   workbenchSettingsAgentDetailHistoryTitle: "History",
   workbenchSettingsAgentDetailHistoryHint:
     "Every change to this agent's instructions and capabilities, oldest actions first.",
diff --git a/packages/chat-ui/src/workbench-settings/agents-section.tsx b/packages/chat-ui/src/workbench-settings/agents-section.tsx
index ee45f8040..d5f8e2ee1 100644
--- a/packages/chat-ui/src/workbench-settings/agents-section.tsx
+++ b/packages/chat-ui/src/workbench-settings/agents-section.tsx
@@ -238,20 +238,29 @@ function AgentDetailEditor({
   const [catalogState, setCatalogState] = useState<CatalogState>({
     kind: "loading",
   });
+  const [catalogReloadKey, setCatalogReloadKey] = useState(0);
 
   useEffect(() => {
     let cancelled = false;
+    setCatalogState({ kind: "loading" });
     getResolvedCatalog(tenantId)
       .then((models) => {
         if (!cancelled) setCatalogState({ kind: "ready", models });
       })
-      .catch(() => {
-        if (!cancelled) setCatalogState({ kind: "error" });
+      .catch((cause: unknown) => {
+        if (cancelled) return;
+        setCatalogState({
+          kind: "error",
+          message: describeChatError(
+            cause,
+            CHAT_STRINGS.workbenchSettingsAgentDetailCatalogError,
+          ),
+        });
       });
     return () => {
       cancelled = true;
     };
-  }, [tenantId]);
+  }, [tenantId, catalogReloadKey]);
 
   useEffect(() => {
     let cancelled = false;
@@ -345,6 +354,7 @@ function AgentDetailEditor({
         agent={agent}
         detail={state.detail}
         catalogState={catalogState}
+        onRetryCatalog={() => setCatalogReloadKey((value) => value + 1)}
         onChanged={(detail) => setState({ kind: "ready", detail })}
       />
 
@@ -430,7 +440,7 @@ type ModelOption = { readonly canonicalName: string; readonly label: string };
 
 type CatalogState =
   | { readonly kind: "loading" }
-  | { readonly kind: "error" }
+  | { readonly kind: "error"; readonly message: string }
   | { readonly kind: "ready"; readonly models: readonly ModelInfo[] };
 
 /** Only a model with at least one offering is actually launchable for this
@@ -479,6 +489,7 @@ function ModelSelect({
   agent,
   detail,
   catalogState,
+  onRetryCatalog,
   onChanged,
 }: {
   readonly tenantId: string;
@@ -486,6 +497,7 @@ function ModelSelect({
   readonly agent: WorkbenchAgent;
   readonly detail: AgentDetail;
   readonly catalogState: CatalogState;
+  readonly onRetryCatalog: () => void;
   readonly onChanged: (detail: AgentDetail) => void;
 }) {
   const [saving, setSaving] = useState(false);
@@ -534,7 +546,11 @@ function ModelSelect({
       <select
         value={detail.model ?? ""}
         onChange={(event) => handleChange(event.target.value)}
-        disabled={saving || catalogState.kind === "loading"}
+        disabled={
+          saving ||
+          catalogState.kind === "loading" ||
+          catalogState.kind === "error"
+        }
       >
         {detail.model === undefined ? (
           <option value="">
@@ -557,6 +573,26 @@ function ModelSelect({
           {CHAT_STRINGS.workbenchSettingsAgentDetailNoConnectedModels}
         </p>
       ) : null}
+      {catalogState.kind === "error" ? (
+        <>
+          <p className="chat-dialog-error" role="alert">
+            {catalogState.message}
+          </p>
+          <div className="chat-settings-field-actions">
+            <Button
+              type="button"
+              variant="outline"
+              size="sm"
+              onClick={onRetryCatalog}
+            >
+              {CHAT_STRINGS.workbenchSettingsAgentDetailCatalogRetryAction}
+            </Button>
+            <a href="/settings/connections">
+              {CHAT_STRINGS.workbenchSettingsAgentDetailCatalogSettingsAction}
+            </a>
+          </div>
+        </>
+      ) : null}
       {error !== null ? (
         <p className="chat-dialog-error" role="alert">
           {error}
diff --git a/packages/chat-ui/test/agents-section.test.tsx b/packages/chat-ui/test/agents-section.test.tsx
index d3d1f90ed..d5fc8c6ff 100644
--- a/packages/chat-ui/test/agents-section.test.tsx
+++ b/packages/chat-ui/test/agents-section.test.tsx
@@ -70,6 +70,14 @@ function stubFetch(options: {
   readonly catalogModels?: readonly (ModelFixture & {
     readonly offerings: readonly OfferingFixture[];
   })[];
+  /** When true, every catalog (`/models`) read fails. */
+  readonly catalogFails?: boolean;
+  /** HTTP status for a failing catalog read (default 500). */
+  readonly catalogFailStatus?: number;
+  /** When true, a failing catalog read throws (network), not an HTTP envelope. */
+  readonly catalogNetworkFails?: boolean;
+  /** Fail the first N catalog reads, then succeed — used to exercise Retry. */
+  readonly catalogFailUntil?: number;
   readonly addCapabilityFails?: boolean;
   readonly restoreFails?: boolean;
   readonly onSave?: (
@@ -100,6 +108,7 @@ function stubFetch(options: {
       offerings: [{ providerName: "anthropic" }],
     },
   ];
+  let catalogCalls = 0;
 
   globalThis.fetch = (async (input: RequestInfo | URL, init?: RequestInit) => {
     const path = typeof input === "string" ? input : String(input);
@@ -127,6 +136,29 @@ function stubFetch(options: {
       return json({ settings: {}, contextWindow: 20 });
     }
     if (/\/models$/.test(path)) {
+      catalogCalls += 1;
+      const catalogShouldFail =
+        options.catalogFails === true ||
+        options.catalogNetworkFails === true ||
+        options.catalogFailStatus !== undefined ||
+        (options.catalogFailUntil !== undefined &&
+          catalogCalls <= options.catalogFailUntil);
+      if (catalogShouldFail) {
+        if (options.catalogNetworkFails === true) {
+          throw new TypeError("Failed to fetch");
+        }
+        const status = options.catalogFailStatus ?? 500;
+        return json(
+          {
+            error: {
+              code: status === 401 ? "unauthenticated" : "internal",
+              userMessage: status === 401 ? "signed out boom" : "catalog boom",
+              refId: "ref_catalog",
+            },
+          },
+          status,
+        );
+      }
       return json(
         catalogModels.map((model, index) => ({
           id: `model_${String(index)}`,
@@ -859,6 +891,93 @@ describe("Agents section — Model select (CL-6272.3)", () => {
     expect(modelSelect(el)?.value).toBe("");
     expect(modelSelect(el)?.options[0]?.textContent).toBe("No model set");
   });
+
+  test("a catalog load failure reads as an error, not an empty picker (CL-6831)", async () => {
+    stubFetch({ catalogFails: true });
+    const el = mount(baseProps());
+    await settle();
+    openAgent(el, "myra");
+    await settle();
+
+    const select = modelSelect(el);
+    expect(select?.disabled).toBe(true);
+
+    const alert = el.querySelector(".chat-dialog-error")?.textContent;
+    expect(alert).toBe("catalog boom");
+    expect(alert).not.toBe("Couldn't load the models.");
+    expect(el.textContent).not.toContain(
+      "No connected providers yet — connect one in Shared Settings.",
+    );
+    expect(el.textContent).not.toContain("No connected providers yet");
+
+    expect(findButton(el, "Retry")).toBeDefined();
+    const settingsHop = el.querySelector(
+      'a[href="/settings/connections"]',
+    ) as HTMLAnchorElement | null;
+    expect(settingsHop).not.toBeNull();
+    expect(settingsHop?.textContent).toBe("Shared Settings");
+  });
+
+  test("a catalog 401 reads as signed-out copy, not the envelope or generic fallback", async () => {
+    stubFetch({ catalogFailStatus: 401 });
+    const el = mount(baseProps());
+    await settle();
+    openAgent(el, "myra");
+    await settle();
+
+    const alert = el.querySelector(".chat-dialog-error")?.textContent;
+    expect(alert).toBe("You're signed out. Sign in again to continue.");
+    expect(alert).not.toBe("signed out boom");
+    expect(alert).not.toBe("Couldn't load the models.");
+  });
+
+  test("a catalog network failure reads as a connection error, not the generic fallback", async () => {
+    stubFetch({ catalogNetworkFails: true });
+    const el = mount(baseProps());
+    await settle();
+    openAgent(el, "myra");
+    await settle();
+
+    const alert = el.querySelector(".chat-dialog-error")?.textContent;
+    expect(alert).toBe(
+      "Couldn't reach the server. Check your connection and try again.",
+    );
+    expect(alert).not.toBe("Couldn't load the models.");
+  });
+
+  test("Retry after a catalog load failure recovers the picker", async () => {
+    stubFetch({
+      catalogFailUntil: 1,
+      catalogModels: [
+        {
+          canonicalName: "anthropic/claude-sonnet",
+          displayName: "Claude Sonnet",
+          offerings: [{ providerName: "anthropic" }],
+        },
+      ],
+    });
+    const el = mount(baseProps());
+    await settle();
+    openAgent(el, "myra");
+    await settle();
+
+    expect(modelSelect(el)?.disabled).toBe(true);
+    expect(el.querySelector(".chat-dialog-error")?.textContent).toBe(
+      "catalog boom",
+    );
+
+    act(() => {
+      findButton(el, "Retry")?.click();
+    });
+    await settle();
+
+    expect(el.querySelector(".chat-dialog-error")).toBeNull();
+    const select = modelSelect(el);
+    expect(select?.disabled).toBe(false);
+    expect(
+      Array.from(select?.options ?? []).map((option) => option.textContent),
+    ).toContain("Claude Sonnet · Anthropic");
+  });
 });
 
 describe("Agents section — History", () => {
diff --git a/packages/chat-ui/test/api.test.ts b/packages/chat-ui/test/api.test.ts
index 2094503cf..0685467cd 100644
--- a/packages/chat-ui/test/api.test.ts
+++ b/packages/chat-ui/test/api.test.ts
@@ -5,9 +5,11 @@
 import { afterEach, describe, expect, test } from "bun:test";
 
 import { UnauthenticatedError } from "@corbits/api-query";
+import { InferenceSettingsApiError } from "@corbits/inference-settings";
 import {
   ChatApiError,
   createWorkbench,
+  describeChatError,
   runDisplayName,
   inviteAgent,
   JIMMY_QUICK_CREATE,
@@ -745,3 +747,52 @@ describe("runDisplayName", () => {
     ).toBe("Untitled agent");
   });
 });
+
+describe("describeChatError", () => {
+  const fallback = "Couldn't load the models.";
+
+  test("surfaces an InferenceSettingsApiError envelope userMessage on 500", () => {
+    expect(
+      describeChatError(
+        new InferenceSettingsApiError("catalog boom", 500),
+        fallback,
+      ),
+    ).toBe("catalog boom");
+  });
+
+  test("maps an InferenceSettingsApiError 401 the same way as ChatApiError", () => {
+    expect(
+      describeChatError(
+        new InferenceSettingsApiError("signed out boom", 401),
+        fallback,
+      ),
+    ).toBe("You're signed out. Sign in again to continue.");
+    expect(describeChatError(new ChatApiError("boom", 401), fallback)).toBe(
+      "You're signed out. Sign in again to continue.",
+    );
+  });
+
+  test("maps a network InferenceSettingsApiError the same way as ChatApiError", () => {
+    expect(
+      describeChatError(
+        new InferenceSettingsApiError("Failed to fetch"),
+        fallback,
+      ),
+    ).toBe("Couldn't reach the server. Check your connection and try again.");
+    expect(
+      describeChatError(new ChatApiError("Failed to fetch"), fallback),
+    ).toBe("Couldn't reach the server. Check your connection and try again.");
+  });
+
+  test("never leaks a ChatApiError path on 500", () => {
+    expect(
+      describeChatError(
+        new ChatApiError(
+          "The server answered 500 for /api/tenants/tnt_1/models.",
+          500,
+        ),
+        fallback,
+      ),
+    ).toBe("Something went wrong on our end. Try again in a moment.");
+  });
+});