diff --git a/tests/test_plugin_cli_registration.py b/tests/test_plugin_cli_registration.py
new file mode 100644
index 0000000000..8dd8b193cb
--- /dev/null
+++ b/tests/test_plugin_cli_registration.py
@@ -0,0 +1,225 @@
+"""Tests for plugin CLI registration system.
+
+Covers:
+  - PluginContext.register_cli_command()
+  - PluginManager._cli_commands storage
+  - get_plugin_cli_commands() convenience function
+  - Memory plugin CLI discovery (discover_plugin_cli_commands)
+  - Honcho register_cli() builds correct argparse tree
+"""
+
+import argparse
+import os
+import sys
+from pathlib import Path
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+from hermes_cli.plugins import (
+    PluginContext,
+    PluginManager,
+    PluginManifest,
+    get_plugin_cli_commands,
+)
+
+
+# ── PluginContext.register_cli_command ─────────────────────────────────────
+
+
+class TestRegisterCliCommand:
+    def _make_ctx(self):
+        mgr = PluginManager()
+        manifest = PluginManifest(name="test-plugin")
+        return PluginContext(manifest, mgr), mgr
+
+    def test_registers_command(self):
+        ctx, mgr = self._make_ctx()
+        setup = MagicMock()
+        handler = MagicMock()
+        ctx.register_cli_command(
+            name="mycmd",
+            help="Do something",
+            setup_fn=setup,
+            handler_fn=handler,
+            description="Full description",
+        )
+        assert "mycmd" in mgr._cli_commands
+        entry = mgr._cli_commands["mycmd"]
+        assert entry["name"] == "mycmd"
+        assert entry["help"] == "Do something"
+        assert entry["setup_fn"] is setup
+        assert entry["handler_fn"] is handler
+        assert entry["plugin"] == "test-plugin"
+
+    def test_overwrites_on_duplicate(self):
+        ctx, mgr = self._make_ctx()
+        ctx.register_cli_command("x", "first", MagicMock())
+        ctx.register_cli_command("x", "second", MagicMock())
+        assert mgr._cli_commands["x"]["help"] == "second"
+
+    def test_handler_optional(self):
+        ctx, mgr = self._make_ctx()
+        ctx.register_cli_command("nocb", "test", MagicMock())
+        assert mgr._cli_commands["nocb"]["handler_fn"] is None
+
+
+class TestGetPluginCliCommands:
+    def test_returns_dict(self):
+        mgr = PluginManager()
+        mgr._cli_commands["foo"] = {"name": "foo", "help": "bar"}
+        with patch("hermes_cli.plugins.get_plugin_manager", return_value=mgr):
+            cmds = get_plugin_cli_commands()
+        assert cmds == {"foo": {"name": "foo", "help": "bar"}}
+        # Top-level is a copy — adding to result doesn't affect manager
+        cmds["new"] = {"name": "new"}
+        assert "new" not in mgr._cli_commands
+
+
+# ── Memory plugin CLI discovery ───────────────────────────────────────────
+
+
+class TestMemoryPluginCliDiscovery:
+    def test_discovers_plugin_with_register_cli(self, tmp_path, monkeypatch):
+        """A memory plugin dir with cli.py containing register_cli is discovered."""
+        plugin_dir = tmp_path / "testplugin"
+        plugin_dir.mkdir()
+        (plugin_dir / "__init__.py").write_text("pass\n")
+        (plugin_dir / "cli.py").write_text(
+            "def register_cli(subparser):\n"
+            "    subparser.add_argument('--test')\n"
+            "\n"
+            "def testplugin_command(args):\n"
+            "    pass\n"
+        )
+        (plugin_dir / "plugin.yaml").write_text(
+            "name: testplugin\ndescription: A test plugin\n"
+        )
+
+        # Patch _MEMORY_PLUGINS_DIR to our tmp dir
+        import plugins.memory as pm
+        original_dir = pm._MEMORY_PLUGINS_DIR
+
+        # Clear any cached module to force reimport
+        mod_key = "plugins.memory.testplugin.cli"
+        sys.modules.pop(mod_key, None)
+
+        monkeypatch.setattr(pm, "_MEMORY_PLUGINS_DIR", tmp_path)
+        try:
+            cmds = pm.discover_plugin_cli_commands()
+        finally:
+            monkeypatch.setattr(pm, "_MEMORY_PLUGINS_DIR", original_dir)
+            sys.modules.pop(mod_key, None)
+
+        assert len(cmds) == 1
+        assert cmds[0]["name"] == "testplugin"
+        assert cmds[0]["help"] == "A test plugin"
+        assert callable(cmds[0]["setup_fn"])
+        assert cmds[0]["handler_fn"].__name__ == "testplugin_command"
+
+    def test_skips_plugin_without_register_cli(self, tmp_path, monkeypatch):
+        """A memory plugin with cli.py but no register_cli is skipped."""
+        plugin_dir = tmp_path / "noplugin"
+        plugin_dir.mkdir()
+        (plugin_dir / "__init__.py").write_text("pass\n")
+        (plugin_dir / "cli.py").write_text("def some_other_fn():\n    pass\n")
+
+        import plugins.memory as pm
+        original_dir = pm._MEMORY_PLUGINS_DIR
+        monkeypatch.setattr(pm, "_MEMORY_PLUGINS_DIR", tmp_path)
+        try:
+            cmds = pm.discover_plugin_cli_commands()
+        finally:
+            monkeypatch.setattr(pm, "_MEMORY_PLUGINS_DIR", original_dir)
+            sys.modules.pop("plugins.memory.noplugin.cli", None)
+
+        assert len(cmds) == 0
+
+    def test_skips_plugin_without_cli_py(self, tmp_path, monkeypatch):
+        """A memory plugin dir without cli.py is skipped."""
+        plugin_dir = tmp_path / "nocli"
+        plugin_dir.mkdir()
+        (plugin_dir / "__init__.py").write_text("pass\n")
+
+        import plugins.memory as pm
+        original_dir = pm._MEMORY_PLUGINS_DIR
+        monkeypatch.setattr(pm, "_MEMORY_PLUGINS_DIR", tmp_path)
+        try:
+            cmds = pm.discover_plugin_cli_commands()
+        finally:
+            monkeypatch.setattr(pm, "_MEMORY_PLUGINS_DIR", original_dir)
+
+        assert len(cmds) == 0
+
+
+# ── Honcho register_cli ──────────────────────────────────────────────────
+
+
+class TestHonchoRegisterCli:
+    def test_builds_subcommand_tree(self):
+        """register_cli creates the expected subparser tree."""
+        from plugins.memory.honcho.cli import register_cli
+
+        parser = argparse.ArgumentParser()
+        register_cli(parser)
+
+        # Verify key subcommands exist by parsing them
+        args = parser.parse_args(["status"])
+        assert args.honcho_command == "status"
+
+        args = parser.parse_args(["peer", "--user", "alice"])
+        assert args.honcho_command == "peer"
+        assert args.user == "alice"
+
+        args = parser.parse_args(["mode", "tools"])
+        assert args.honcho_command == "mode"
+        assert args.mode == "tools"
+
+        args = parser.parse_args(["tokens", "--context", "500"])
+        assert args.honcho_command == "tokens"
+        assert args.context == 500
+
+        args = parser.parse_args(["--target-profile", "coder", "status"])
+        assert args.target_profile == "coder"
+        assert args.honcho_command == "status"
+
+    def test_setup_redirects_to_memory_setup(self):
+        """hermes honcho setup redirects to memory setup."""
+        from plugins.memory.honcho.cli import register_cli
+
+        parser = argparse.ArgumentParser()
+        register_cli(parser)
+        args = parser.parse_args(["setup"])
+        assert args.honcho_command == "setup"
+
+    def test_mode_choices_are_recall_modes(self):
+        """Mode subcommand uses recall mode choices (hybrid/context/tools)."""
+        from plugins.memory.honcho.cli import register_cli
+
+        parser = argparse.ArgumentParser()
+        register_cli(parser)
+
+        # Valid recall modes should parse
+        for mode in ("hybrid", "context", "tools"):
+            args = parser.parse_args(["mode", mode])
+            assert args.mode == mode
+
+        # Old memoryMode values should fail
+        with pytest.raises(SystemExit):
+            parser.parse_args(["mode", "honcho"])
+
+
+# ── ProviderCollector no-op ──────────────────────────────────────────────
+
+
+class TestProviderCollectorCliNoop:
+    def test_register_cli_command_is_noop(self):
+        """_ProviderCollector.register_cli_command is a no-op (doesn't crash)."""
+        from plugins.memory import _ProviderCollector
+
+        collector = _ProviderCollector()
+        collector.register_cli_command(
+            name="test", help="test", setup_fn=lambda s: None
+        )
+        # Should not store anything — CLI is discovered via file convention
+        assert not hasattr(collector, "_cli_commands")