feat: add interactive model download and empty-model fallback to init

Prompts user to download recommended model during jarvis init.
Adds --no-download flag for CI. Shows helpful message when no
model fits available memory. Adds exo/nexa next-steps text.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/openjarvis/cli/init_cmd.py

@@ -10,10 +10,12 @@ from rich.console import Console
 from rich.markup import escape
 from rich.panel import Panel
 
+from openjarvis.cli.model import find_model_spec, hf_download, ollama_pull
 from openjarvis.core.config import (
     DEFAULT_CONFIG_DIR,
     DEFAULT_CONFIG_PATH,
     detect_hardware,
+    estimated_download_gb,
     generate_default_toml,
     generate_minimal_toml,
     recommend_engine,
@@ -132,10 +134,58 @@ def _next_steps_text(engine: str, model: str = "") -> str:
             "\n"
             "  Run `jarvis doctor` to verify your setup."
         ),
+        "exo": (
+            "Next steps:\n\n"
+            "  1. Install and start Exo:\n"
+            "     pip install exo\n"
+            "     exo\n\n"
+            "  2. Try it out:\n"
+            "     jarvis ask \"Hello\"\n\n"
+            "  Run `jarvis doctor` to verify your setup."
+        ),
+        "nexa": (
+            "Next steps:\n\n"
+            "  1. Install and start Nexa:\n"
+            "     pip install nexaai\n"
+            "     nexa server\n\n"
+            "  2. Try it out:\n"
+            "     jarvis ask \"Hello\"\n\n"
+            "  Run `jarvis doctor` to verify your setup."
+        ),
     }
     return steps.get(engine, steps["ollama"])
 
 
+def _do_download(engine: str, model: str, spec, console: Console) -> None:
+    """Dispatch model download based on engine type."""
+    import os
+    if engine == "ollama":
+        host = os.environ.get("OLLAMA_HOST", "http://localhost:11434").rstrip("/")
+        ollama_pull(host, model, console)
+    elif engine == "llamacpp":
+        repo = spec.metadata.get("hf_repo", "")
+        gguf = spec.metadata.get("gguf_file", "")
+        if repo and gguf:
+            console.print(f"  Downloading [cyan]{gguf}[/cyan] from {repo}...")
+            hf_download(repo, gguf, console)
+        else:
+            console.print(f"  [yellow]No GGUF download info for {model}[/yellow]")
+    elif engine == "mlx":
+        mlx_repo = spec.metadata.get("mlx_repo", "")
+        if mlx_repo:
+            console.print(f"  Downloading [cyan]{mlx_repo}[/cyan]...")
+            hf_download(mlx_repo, None, console)
+        else:
+            console.print(f"  [yellow]No MLX repo info for {model}[/yellow]")
+    elif engine in ("vllm", "sglang"):
+        console.print(
+            f"  [cyan]{model}[/cyan] will download automatically when "
+            f"{engine} starts serving it."
+        )
+    else:
+        console.print(f"  Download {model} through the {engine} interface.")
+
+
 @click.command()
 @click.option(
     "--force", is_flag=True, help="Overwrite existing config without prompting."
@@ -157,11 +207,15 @@ def _next_steps_text(engine: str, model: str = "") -> str:
     default=None,
     help="Inference engine to use (skips interactive selection).",
 )
+@click.option(
+    "--no-download", is_flag=True, default=False, help="Skip the model download prompt."
+)
 def init(
     force: bool,
     config: Optional[Path],
     full_config: bool = False,
     engine: Optional[str] = None,
+    no_download: bool = False,
 ) -> None:
     """Detect hardware and generate ~/.openjarvis/config.toml."""
     console = Console()
@@ -286,8 +340,24 @@ def init(
 
     selected_engine = engine or recommend_engine(hw)
     model = recommend_model(hw, selected_engine)
-    if model:
-        console.print(f"\n  [bold]Recommended model:[/bold] {model}")
+
+    if not model:
+        console.print(
+            "\n  [yellow]! Not enough memory to run any local model.[/yellow]\n"
+            "  Consider a cloud engine or a machine with more RAM."
+        )
+    else:
+        spec = find_model_spec(model)
+        size_gb = estimated_download_gb(spec.parameter_count_b) if spec else 0
+        console.print(
+            f"\n  [bold]Recommended model:[/bold] {model} (~{size_gb:.1f} GB estimated)"
+        )
+
+        if not no_download and spec:
+            prompt = f"  Download {model} (~{size_gb:.1f} GB estimated) now?"
+            if click.confirm(prompt, default=True):
+                _do_download(selected_engine, model, spec, console)
+
     console.print()
     console.print(
         Panel(

tests/cli/test_init_guidance.py

@@ -20,7 +20,7 @@ class TestInitShowsNextSteps:
             mock.patch("openjarvis.cli.init_cmd.DEFAULT_CONFIG_DIR", config_dir),
             mock.patch("openjarvis.cli.init_cmd.DEFAULT_CONFIG_PATH", config_path),
         ):
-            result = CliRunner().invoke(cli, ["init", "--engine", "llamacpp"])
+            result = CliRunner().invoke(cli, ["init", "--engine", "llamacpp", "--no-download"])
         assert result.exit_code == 0
         assert "Getting Started" in result.output
         assert "jarvis ask" in result.output
@@ -34,7 +34,7 @@ class TestInitShowsNextSteps:
             mock.patch("openjarvis.cli.init_cmd.DEFAULT_CONFIG_DIR", config_dir),
             mock.patch("openjarvis.cli.init_cmd.DEFAULT_CONFIG_PATH", config_path),
         ):
-            result = CliRunner().invoke(cli, ["init", "--engine", "llamacpp"])
+            result = CliRunner().invoke(cli, ["init", "--engine", "llamacpp", "--no-download"])
         assert result.exit_code == 0
         assert "[engine]" in result.output
         assert "[intelligence]" in result.output
@@ -93,7 +93,7 @@ class TestMinimalConfig:
             mock.patch("openjarvis.cli.init_cmd.DEFAULT_CONFIG_DIR", config_dir),
             mock.patch("openjarvis.cli.init_cmd.DEFAULT_CONFIG_PATH", config_path),
         ):
-            result = CliRunner().invoke(cli, ["init", "--engine", "ollama"])
+            result = CliRunner().invoke(cli, ["init", "--engine", "ollama", "--no-download"])
         assert result.exit_code == 0
         content = config_path.read_text()
         # Minimal config should be short
@@ -110,10 +110,87 @@ class TestMinimalConfig:
             mock.patch("openjarvis.cli.init_cmd.DEFAULT_CONFIG_DIR", config_dir),
             mock.patch("openjarvis.cli.init_cmd.DEFAULT_CONFIG_PATH", config_path),
         ):
-            result = CliRunner().invoke(cli, ["init", "--full", "--engine", "ollama"])
+            result = CliRunner().invoke(cli, ["init", "--full", "--engine", "ollama", "--no-download"])
         assert result.exit_code == 0
         content = config_path.read_text()
         # Full config should have many sections
         assert "[engine.ollama]" in content
         assert "[server]" in content
         assert "[security]" in content
+
+
+class TestInitDownloadPrompt:
+    def test_init_shows_download_prompt(self, tmp_path: Path) -> None:
+        config_dir = tmp_path / ".openjarvis"
+        config_path = config_dir / "config.toml"
+        with (
+            mock.patch("openjarvis.cli.init_cmd.DEFAULT_CONFIG_DIR", config_dir),
+            mock.patch("openjarvis.cli.init_cmd.DEFAULT_CONFIG_PATH", config_path),
+        ):
+            result = CliRunner().invoke(cli, ["init", "--engine", "ollama"], input="n\n")
+        assert result.exit_code == 0
+        assert "Download" in result.output and "now?" in result.output
+
+    def test_init_no_download_flag_skips_prompt(self, tmp_path: Path) -> None:
+        config_dir = tmp_path / ".openjarvis"
+        config_path = config_dir / "config.toml"
+        with (
+            mock.patch("openjarvis.cli.init_cmd.DEFAULT_CONFIG_DIR", config_dir),
+            mock.patch("openjarvis.cli.init_cmd.DEFAULT_CONFIG_PATH", config_path),
+        ):
+            result = CliRunner().invoke(cli, ["init", "--engine", "ollama", "--no-download"])
+        assert result.exit_code == 0
+        assert "Download" not in result.output or "now?" not in result.output
+
+
+class TestInitEmptyModelFallback:
+    def test_init_no_model_shows_warning(self, tmp_path: Path) -> None:
+        config_dir = tmp_path / ".openjarvis"
+        config_path = config_dir / "config.toml"
+        with (
+            mock.patch("openjarvis.cli.init_cmd.DEFAULT_CONFIG_DIR", config_dir),
+            mock.patch("openjarvis.cli.init_cmd.DEFAULT_CONFIG_PATH", config_path),
+            mock.patch("openjarvis.cli.init_cmd.recommend_model", return_value=""),
+        ):
+            result = CliRunner().invoke(cli, ["init", "--engine", "llamacpp"])
+        assert result.exit_code == 0
+        assert "Not enough memory" in result.output or "not enough memory" in result.output
+
+
+class TestNextStepsExoNexa:
+    def test_next_steps_exo(self) -> None:
+        text = _next_steps_text("exo")
+        assert "exo" in text.lower()
+        assert "jarvis ask" in text
+        assert "ollama" not in text.lower()
+
+    def test_next_steps_nexa(self) -> None:
+        text = _next_steps_text("nexa")
+        assert "nexa" in text.lower()
+        assert "jarvis ask" in text
+        assert "ollama" not in text.lower()
+
+
+class TestInitDownloadDispatch:
+    def test_init_ollama_download_calls_ollama_pull(self, tmp_path: Path) -> None:
+        config_dir = tmp_path / ".openjarvis"
+        config_path = config_dir / "config.toml"
+        with (
+            mock.patch("openjarvis.cli.init_cmd.DEFAULT_CONFIG_DIR", config_dir),
+            mock.patch("openjarvis.cli.init_cmd.DEFAULT_CONFIG_PATH", config_path),
+            mock.patch("openjarvis.cli.init_cmd.ollama_pull", return_value=True) as mock_pull,
+        ):
+            result = CliRunner().invoke(cli, ["init", "--engine", "ollama"], input="y\n")
+        assert result.exit_code == 0
+        mock_pull.assert_called_once()
+
+    def test_init_vllm_shows_auto_download_message(self, tmp_path: Path) -> None:
+        config_dir = tmp_path / ".openjarvis"
+        config_path = config_dir / "config.toml"
+        with (
+            mock.patch("openjarvis.cli.init_cmd.DEFAULT_CONFIG_DIR", config_dir),
+            mock.patch("openjarvis.cli.init_cmd.DEFAULT_CONFIG_PATH", config_path),
+        ):
+            result = CliRunner().invoke(cli, ["init", "--engine", "vllm"], input="y\n")
+        assert result.exit_code == 0
+        assert "automatically" in result.output