GUI: multi-field provider credentials and add-model family dropdown

Test button and saved pill follow the required-secret field (or the first field for
cloud providers); Bedrock/Vertex add-model rows get a family selector.

surfaces/gui/src/components/ModelChecklist.test.tsx

@@ -0,0 +1,72 @@
+// Add-model family dropdown for the cloud-account providers: the family choice folds
+// into the model id (`bedrock:claude/…`, `vertex:openweight/…`); plain providers keep
+// the bare add-model row.
+import { afterEach, describe, expect, it, vi } from "vitest";
+import { cleanup, fireEvent, render, screen } from "@testing-library/react";
+import { ModelChecklist } from "./ModelChecklist";
+
+vi.mock("../api", () => ({
+  addModel: vi.fn(async (id: string) => ({ ok: true, models: [id], model: id })),
+  removeModel: vi.fn(async () => ({ ok: true, models: [], model: "" })),
+  setDefaultModel: vi.fn(async () => ({ ok: true })),
+  getSettings: vi.fn(async () => ({ models: [], model: "" })),
+}));
+
+import { addModel } from "../api";
+
+afterEach(() => {
+  cleanup();
+  vi.clearAllMocks();
+});
+
+const KNOWN = ["openai", "anthropic", "bedrock", "vertex", "openrouter"];
+
+function renderList(provider: string) {
+  return render(
+    <ModelChecklist
+      provider={provider}
+      knownProviders={KNOWN}
+      suggested={[]}
+      curated={[]}
+      defaultModel=""
+      onChanged={() => {}}
+    />,
+  );
+}
+
+function addTyped(id: string) {
+  fireEvent.change(screen.getByPlaceholderText("Add another model…"), {
+    target: { value: id },
+  });
+  fireEvent.click(screen.getByText("Add"));
+}
+
+describe("ModelChecklist add-model family dropdown", () => {
+  it("folds the selected vertex family into the id", async () => {
+    renderList("vertex");
+    fireEvent.change(screen.getByTestId("mlist-family"), {
+      target: { value: "openweight" },
+    });
+    addTyped("meta/llama-4-maverick-17b-128e-instruct-maas");
+    expect(addModel).toHaveBeenCalledWith(
+      "vertex:openweight/meta/llama-4-maverick-17b-128e-instruct-maas",
+    );
+  });
+
+  it("defaults bedrock to the Claude family and keeps a typed family verbatim", async () => {
+    renderList("bedrock");
+    addTyped("anthropic.claude-sonnet-4-6-v1:0");
+    expect(addModel).toHaveBeenCalledWith(
+      "bedrock:claude/anthropic.claude-sonnet-4-6-v1:0",
+    );
+    addTyped("other/amazon.nova-2-pro-v1:0");
+    expect(addModel).toHaveBeenLastCalledWith("bedrock:other/amazon.nova-2-pro-v1:0");
+  });
+
+  it("shows no family dropdown for plain providers", async () => {
+    renderList("openrouter");
+    expect(screen.queryByTestId("mlist-family")).toBeNull();
+    addTyped("z-ai/glm-5.2");
+    expect(addModel).toHaveBeenCalledWith("openrouter:z-ai/glm-5.2");
+  });
+});

surfaces/gui/src/components/ModelChecklist.tsx

@@ -1,6 +1,22 @@
 import { useState } from "react";
 import { addModel, getSettings, removeModel, setDefaultModel } from "../api";
 
+// Cloud-account providers dispatch by a family segment baked into the model id
+// (`bedrock:claude/…`, `vertex:openweight/…`). The add-model row shows a dropdown so
+// users pick the family instead of memorizing the prefix; curated matrix ids already
+// carry theirs.
+const MODEL_FAMILIES: Record<string, { value: string; label: string }[]> = {
+  bedrock: [
+    { value: "claude", label: "Claude family" },
+    { value: "other", label: "Other models" },
+  ],
+  vertex: [
+    { value: "gemini", label: "Gemini family" },
+    { value: "claude", label: "Claude family" },
+    { value: "openweight", label: "Open-weight" },
+  ],
+};
+
 // One provider's models as a checklist: tick = shown in the composer's model picker (the
 // curated list), the black "default" badge marks the model new sessions use, and hovering any
 // other row reveals "Make default". A free-type row below adds models by hand, so brand-new
@@ -23,6 +39,8 @@ export function ModelChecklist({
   onChanged: (next: { models: string[]; model: string }) => void;
 }) {
   const [draft, setDraft] = useState("");
+  const families = MODEL_FAMILIES[provider];
+  const [family, setFamily] = useState(families?.[0]?.value || "");
 
   const provOf = (id: string) => {
     const i = id.indexOf(":");
@@ -52,8 +70,12 @@ export function ModelChecklist({
     await refresh();
   };
   const add = async () => {
-    const typed = draft.trim();
+    let typed = draft.trim();
     if (!typed) return;
+    // Fold the family choice into the id unless the user already typed one.
+    if (families && !families.some((f) => typed.startsWith(`${f.value}/`))) {
+      typed = `${family}/${typed}`;
+    }
     const res = await addModel(prefixed(typed));
     if (res.ok) {
       setDraft("");
@@ -90,6 +112,20 @@ export function ModelChecklist({
         );
       })}
       <div className="mlist-add">
+        {families && (
+          <select
+            value={family}
+            onChange={(e) => setFamily(e.target.value)}
+            aria-label="Model family"
+            data-testid="mlist-family"
+          >
+            {families.map((f) => (
+              <option key={f.value} value={f.value}>
+                {f.label}
+              </option>
+            ))}
+          </select>
+        )}
         <input
           placeholder="Add another model…"
           value={draft}