feat: ensure-agent + resolve npm-global CLIs without PATH

Add guided multi-select ensure-agent, resolve backend binaries via npm
prefix when not on PATH, and optionally persist npm bin in shell rc.

tests/test_ensure_agent_cmd.py

@@ -0,0 +1,99 @@
+"""Tests for ``myagents ensure-agent`` multi-select."""
+
+from __future__ import annotations
+
+from unittest.mock import patch
+
+from click.testing import CliRunner
+
+from myagents.commands.ensure_agent import ensure_agent_cmd, run_ensure_agents
+
+
+def test_ensure_agent_all_present() -> None:
+    with patch(
+        "myagents.commands.ensure_agent.backend_available", return_value=True
+    ):
+        result = CliRunner().invoke(ensure_agent_cmd, [])
+    assert result.exit_code == 0, result.output
+    assert "ready" in result.output.lower()
+
+
+def test_run_ensure_agents_noninteractive_installs_missing() -> None:
+    def available(name: str) -> bool:
+        return name != "claude"
+
+    with (
+        patch(
+            "myagents.commands.ensure_agent.backend_available",
+            side_effect=available,
+        ),
+        patch(
+            "myagents.commands.ensure_agent._is_interactive", return_value=False
+        ),
+        patch(
+            "myagents.commands.ensure_agent.ensure_backend", return_value=True
+        ) as ensure,
+    ):
+        still = run_ensure_agents()
+    assert still == []
+    assert any(c.args[0] == "claude" for c in ensure.call_args_list)
+    # Selected path uses yes=True (no second prompt).
+    assert ensure.call_args.kwargs.get("yes") is True
+
+
+def test_run_ensure_agents_interactive_select() -> None:
+    def available(name: str) -> bool:
+        return name not in ("claude", "codex")
+
+    with (
+        patch(
+            "myagents.commands.ensure_agent.backend_available",
+            side_effect=available,
+        ),
+        patch(
+            "myagents.commands.ensure_agent._is_interactive", return_value=True
+        ),
+        patch(
+            "myagents.commands.ensure_agent.Prompt.ask", return_value="1"
+        ),
+        patch(
+            "myagents.commands.ensure_agent.ensure_backend", return_value=True
+        ) as ensure,
+    ):
+        still = run_ensure_agents()
+    # Only first missing (claude) selected.
+    assert ensure.call_count == 1
+    assert ensure.call_args.args[0] == "claude"
+    assert "codex" in still
+
+
+def test_run_ensure_agents_prefer_on_enter() -> None:
+    def available(name: str) -> bool:
+        return name not in ("claude", "codex")
+
+    with (
+        patch(
+            "myagents.commands.ensure_agent.backend_available",
+            side_effect=available,
+        ),
+        patch(
+            "myagents.commands.ensure_agent._is_interactive", return_value=True
+        ),
+        patch(
+            "myagents.commands.ensure_agent.Prompt.ask", return_value=""
+        ),
+        patch(
+            "myagents.commands.ensure_agent.ensure_backend", return_value=True
+        ) as ensure,
+    ):
+        still = run_ensure_agents(prefer=["codex"])
+    assert ensure.call_count == 1
+    assert ensure.call_args.args[0] == "codex"
+    assert "claude" in still
+
+
+def test_ensure_agent_help() -> None:
+    result = CliRunner().invoke(ensure_agent_cmd, ["--help"])
+    assert result.exit_code == 0
+    assert "multi-select" in result.output.lower() or "ensure-agent" in result.output
+    assert "--yes" not in result.output

tests/test_ensure_backend.py

@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+import os
 from pathlib import Path
 from unittest.mock import patch
 
@@ -63,21 +64,31 @@ class TestEnsureBackend:
             assert launcher_mod.ensure_backend("hermes") is False
 
 
-class TestResolveInstalledBinary:
-    def test_falls_back_to_npm_global_bin(self, tmp_path: Path) -> None:
+class TestResolveBackendBinary:
+    def test_falls_back_to_npm_global_bin(self, tmp_path: Path, monkeypatch) -> None:
         bin_dir = tmp_path / "bin"
         bin_dir.mkdir()
         claude = bin_dir / "claude"
         claude.write_text("#!/bin/sh\n")
         claude.chmod(0o755)
-        cfg = launcher_mod._BACKENDS["claude"]
+        monkeypatch.delenv("CLAUDE_BIN", raising=False)
         with (
-            patch.object(
-                launcher_mod, "_resolve_backend_binary", return_value=None
-            ),
+            patch.object(launcher_mod.shutil, "which", return_value=None),
             patch.object(launcher_mod, "_npm_global_bin", return_value=bin_dir),
         ):
-            assert launcher_mod._resolve_installed_binary(cfg) == str(claude)
+            assert launcher_mod.resolve_backend_binary("claude") == str(claude)
+
+    def test_ensure_npm_bin_prepends_path(
+        self, tmp_path: Path, monkeypatch
+    ) -> None:
+        bin_dir = tmp_path / "npm-bin"
+        bin_dir.mkdir()
+        monkeypatch.setenv("PATH", "/usr/bin")
+        with patch.object(launcher_mod, "_npm_global_bin", return_value=bin_dir):
+            got = launcher_mod.ensure_npm_bin_on_path(persist=False)
+        assert got == bin_dir
+        assert str(bin_dir) in os.environ["PATH"].split(os.pathsep)
+        assert os.environ["PATH"].split(os.pathsep)[0] == str(bin_dir)
 
 
 class TestOfferInstallGuided: