fix(ui): model/eval picker shows no list when CLI model discovery fails

packages/core/src/services/copilot.ts

@@ -58,8 +58,31 @@ export async function assertCopilotCliReady(): Promise<CopilotCliConfig> {
 export async function listCopilotModels(): Promise<string[]> {
   const config = await assertCopilotCliReady();
   const [cmd, args] = buildExecArgs(config, ["--help"]);
-  const { stdout } = await execFileAsync(cmd, args, { timeout: 5000 });
-  return extractModelChoices(stdout);
+  let stdout = "";
+  let stderr = "";
+  let execError: unknown = null;
+  try {
+    const result = await execFileAsync(cmd, args, { timeout: 5000 });
+    stdout = result.stdout;
+    stderr = result.stderr;
+  } catch (err) {
+    // Some CLIs exit with a non-zero code for --help; try to extract from stderr
+    execError = err;
+    const e = err as { stderr?: string; stdout?: string };
+    stdout = e.stdout ?? "";
+    stderr = e.stderr ?? "";
+  }
+  const fromStdout = extractModelChoices(stdout);
+  if (fromStdout.length > 0) return fromStdout;
+  const fromStderr = extractModelChoices(stderr);
+  if (fromStderr.length > 0) return fromStderr;
+  if (execError) {
+    const e = execError as Error & { stderr?: string; stdout?: string };
+    const details = e.stderr || e.stdout;
+    const detailMsg = details ? `\nCopilot CLI output:\n${details}` : "";
+    throw new Error(`Failed to list Copilot models: ${e.message}${detailMsg}`);
+  }
+  return [];
 }
 
 export function buildExecArgs(config: CopilotCliConfig, extraArgs: string[]): [string, string[]] {
@@ -274,7 +297,7 @@ async function isHeadlessCompatible(config: CopilotCliConfig): Promise<boolean>
   }
 }
 
-function extractModelChoices(helpText: string): string[] {
+export function extractModelChoices(helpText: string): string[] {
   const lines = helpText.split("\n");
   let captured = "";
 

src/services/__tests__/copilot.test.ts

@@ -0,0 +1,37 @@
+import { extractModelChoices } from "@agentrc/core/services/copilot";
+import { describe, expect, it } from "vitest";
+
+describe("extractModelChoices", () => {
+  it("extracts model names from a single-line --help output", () => {
+    const help =
+      '  --model <model>  Model to use (choices: "claude-sonnet-4.5", "claude-sonnet-4", "gpt-4.1")';
+    expect(extractModelChoices(help)).toEqual(["claude-sonnet-4.5", "claude-sonnet-4", "gpt-4.1"]);
+  });
+
+  it("extracts model names when choices span multiple lines", () => {
+    const help = [
+      '  --model <model>  Model to use (choices: "claude-sonnet-4.5",',
+      '                   "claude-sonnet-4", "gpt-4.1")'
+    ].join("\n");
+    expect(extractModelChoices(help)).toEqual(["claude-sonnet-4.5", "claude-sonnet-4", "gpt-4.1"]);
+  });
+
+  it("returns empty array when --model line is absent", () => {
+    const help = "  --output <file>  Output file\n  --quiet           Suppress output";
+    expect(extractModelChoices(help)).toEqual([]);
+  });
+
+  it("returns empty array for empty string", () => {
+    expect(extractModelChoices("")).toEqual([]);
+  });
+
+  it("returns empty array when choices keyword is missing", () => {
+    const help = "  --model <model>  Model to use (default: claude-sonnet-4.5)";
+    expect(extractModelChoices(help)).toEqual([]);
+  });
+
+  it("handles help text written to stderr (same format)", () => {
+    const stderr = '  --model <model>  Model (choices: "gpt-5", "gpt-4.1", "claude-sonnet-4.5")';
+    expect(extractModelChoices(stderr)).toEqual(["gpt-5", "gpt-4.1", "claude-sonnet-4.5"]);
+  });
+});

src/ui/tui.tsx

@@ -273,18 +273,18 @@ export function AgentRCTui({ repoPath, skipAnimation = false }: Props): React.JS
     listCopilotModels()
       .then((models) => {
         if (!active) return;
-        setAvailableModels(models);
-        if (models.length === 0) return;
+        const list = models.length > 0 ? models : PREFERRED_MODELS;
+        setAvailableModels(list);
         setEvalModel((current) =>
-          models.includes(current) ? current : pickBestModel(models, current)
+          list.includes(current) ? current : pickBestModel(list, current)
         );
         setJudgeModel((current) =>
-          models.includes(current) ? current : pickBestModel(models, current)
+          list.includes(current) ? current : pickBestModel(list, current)
         );
       })
       .catch(() => {
         if (!active) return;
-        setAvailableModels([]);
+        setAvailableModels(PREFERRED_MODELS);
       });
     return () => {
       active = false;