feat: add /plan command (#1372)

* feat: add /plan command

* refactor: back /plan with bundled skill

* docs: document /plan skill

tests/test_cli_plan_command.py

@@ -0,0 +1,66 @@
+"""Tests for the /plan CLI slash command."""
+
+from unittest.mock import MagicMock, patch
+
+from agent.skill_commands import scan_skill_commands
+from cli import HermesCLI
+
+
+def _make_cli():
+    cli_obj = HermesCLI.__new__(HermesCLI)
+    cli_obj.config = {}
+    cli_obj.console = MagicMock()
+    cli_obj.agent = None
+    cli_obj.conversation_history = []
+    cli_obj.session_id = "sess-123"
+    cli_obj._pending_input = MagicMock()
+    return cli_obj
+
+
+def _make_plan_skill(skills_dir):
+    skill_dir = skills_dir / "plan"
+    skill_dir.mkdir(parents=True, exist_ok=True)
+    (skill_dir / "SKILL.md").write_text(
+        """---
+name: plan
+description: Plan mode skill.
+---
+
+# Plan
+
+Use the current conversation context when no explicit instruction is provided.
+Save plans under $HERMES_HOME/plans.
+"""
+    )
+
+
+class TestCLIPlanCommand:
+    def test_plan_command_queues_plan_skill_message(self, tmp_path, monkeypatch):
+        monkeypatch.setenv("HERMES_HOME", str(tmp_path))
+        cli_obj = _make_cli()
+
+        with patch("tools.skills_tool.SKILLS_DIR", tmp_path):
+            _make_plan_skill(tmp_path)
+            scan_skill_commands()
+            result = cli_obj.process_command("/plan Add OAuth login")
+
+        assert result is True
+        cli_obj._pending_input.put.assert_called_once()
+        queued = cli_obj._pending_input.put.call_args[0][0]
+        assert "Plan mode skill" in queued
+        assert "Add OAuth login" in queued
+        assert str(tmp_path / "plans") in queued
+        assert "Runtime note:" in queued
+
+    def test_plan_without_args_uses_skill_context_guidance(self, tmp_path, monkeypatch):
+        monkeypatch.setenv("HERMES_HOME", str(tmp_path))
+        cli_obj = _make_cli()
+
+        with patch("tools.skills_tool.SKILLS_DIR", tmp_path):
+            _make_plan_skill(tmp_path)
+            scan_skill_commands()
+            cli_obj.process_command("/plan")
+
+        queued = cli_obj._pending_input.put.call_args[0][0]
+        assert "current conversation context" in queued
+        assert "conversation-plan" in queued