diff --git a/Gradata/src/gradata/cli.py b/Gradata/src/gradata/cli.py
index a752674a..9a4d0eb9 100644
--- a/Gradata/src/gradata/cli.py
+++ b/Gradata/src/gradata/cli.py
@@ -1843,6 +1843,16 @@ def cmd_hooks(args):
     """Manage Claude Code hook integration."""
     action = args.action
     if action == "install":
+        ide = getattr(args, "ide", "claude-code")
+        if ide != "claude-code":
+            # The legacy one-command installer calls `gradata hooks install
+            # --ide <host>`. Claude Code keeps using the richer hook installer
+            # below; other hosts are wired through the adapter-based install
+            # path used by `gradata install --agent <host>`.
+            args.agent = ide
+            _cmd_install_agent(args)
+            return
+
         from gradata.hooks.claude_code import install_hook
 
         project_dir = getattr(args, "project_dir", None)
@@ -2157,6 +2167,12 @@ def main():
 
     p_hooks = sub.add_parser("hooks", help="Manage Claude Code hook integration")
     p_hooks.add_argument("action", choices=["install", "uninstall", "status"], help="Hook action")
+    p_hooks.add_argument(
+        "--ide",
+        choices=["claude-code", "codex"],
+        default="claude-code",
+        help="IDE/agent to wire up for one-command installers (default: claude-code)",
+    )
     p_hooks.add_argument(
         "--profile",
         choices=["minimal", "standard", "strict"],
diff --git a/Gradata/tests/test_install_smoke_matrix.py b/Gradata/tests/test_install_smoke_matrix.py
new file mode 100644
index 00000000..3b7c1a24
--- /dev/null
+++ b/Gradata/tests/test_install_smoke_matrix.py
@@ -0,0 +1,184 @@
+from __future__ import annotations
+
+import json
+import os
+import shutil
+import subprocess
+import sys
+from pathlib import Path
+
+import pytest
+
+
+REPO_ROOT = Path(__file__).resolve().parents[1]
+INSTALLER_JS = REPO_ROOT / "gradata-install" / "bin" / "gradata-install.js"
+
+
+def _cli_env(home: Path, brain: Path) -> dict[str, str]:
+    env = os.environ.copy()
+    for key in list(env):
+        if key.startswith("GRADATA_"):
+            env.pop(key, None)
+    env.update(
+        {
+            "HOME": str(home),
+            "USERPROFILE": str(home),
+            "XDG_CONFIG_HOME": str(home / ".config"),
+            "BRAIN_DIR": str(brain),
+            "PYTHONPATH": str(REPO_ROOT / "src"),
+        }
+    )
+    return env
+
+
+SHOW_HN_SLASH_COMMAND_SKIP = (
+    "GRA-1680: legacy slash-command/one-command installer only accepts "
+    "claude-code and codex before Show HN; use `gradata install --agent <host>` "
+    "for this host until it is promoted into the slash-command path."
+)
+
+
+@pytest.mark.parametrize(
+    ("ide", "expected_config", "expected_text"),
+    [
+        ("claude-code", ".claude/settings.json", "gradata.hooks.inject_brain_rules"),
+        ("codex", ".codex/config.toml", "gradata:codex"),
+        pytest.param(
+            "hermes",
+            ".hermes/config.yaml",
+            "pre_tool_call",
+            marks=pytest.mark.skip(reason=SHOW_HN_SLASH_COMMAND_SKIP),
+        ),
+        pytest.param(
+            "opencode",
+            ".config/opencode/config.json",
+            "preTool",
+            marks=pytest.mark.skip(reason=SHOW_HN_SLASH_COMMAND_SKIP),
+        ),
+    ],
+)
+def test_hooks_install_smoke_matrix_for_show_hn_hosts(
+    tmp_path: Path, ide: str, expected_config: str, expected_text: str
+) -> None:
+    """Slash-command hook install smoke matrix used by Show HN completion notes.
+
+    Runs with a mocked HOME/BRAIN_DIR so it proves the installer writes the
+    host-specific hook config without touching a developer's real agent config.
+    """
+    home = tmp_path / "home"
+    brain = tmp_path / "brain"
+    project = tmp_path / "project"
+    brain.mkdir(parents=True)
+    project.mkdir()
+
+    result = subprocess.run(
+        [
+            sys.executable,
+            "-m",
+            "gradata.cli",
+            "hooks",
+            "install",
+            "--ide",
+            ide,
+            "--project-dir",
+            str(project),
+        ],
+        cwd=REPO_ROOT,
+        env=_cli_env(home, brain),
+        text=True,
+        capture_output=True,
+        check=False,
+    )
+
+    assert result.returncode == 0, result.stderr or result.stdout
+    config = home / expected_config
+    assert config.is_file(), f"missing {ide} config at {config}"
+    text = config.read_text(encoding="utf-8")
+    assert expected_text in text
+    if ide != "claude-code":
+        assert str(brain) in text
+
+    if ide == "claude-code":
+        # Claude's richer hook installer should also copy/register the bundled
+        # JS assets when project-dir is supplied.
+        assert (project / ".claude/hooks/user-prompt/handoff-watchdog.js").is_file()
+        data = json.loads(text)
+        assert "PreToolUse" in data.get("hooks", {})
+
+
+@pytest.mark.skipif(shutil.which("node") is None, reason="node runtime not installed")
+@pytest.mark.parametrize(
+    ("ide", "expected_hook_args"),
+    [
+        ("claude-code", ["hooks", "install"]),
+        ("codex", ["hooks", "install", "--ide", "codex"]),
+        pytest.param(
+            "hermes",
+            ["hooks", "install", "--ide", "hermes"],
+            marks=pytest.mark.skip(reason=SHOW_HN_SLASH_COMMAND_SKIP),
+        ),
+        pytest.param(
+            "opencode",
+            ["hooks", "install", "--ide", "opencode"],
+            marks=pytest.mark.skip(reason=SHOW_HN_SLASH_COMMAND_SKIP),
+        ),
+    ],
+)
+def test_one_command_installer_routes_hook_install_matrix(
+    tmp_path: Path, ide: str, expected_hook_args: list[str]
+) -> None:
+    """Legacy one-command installer smoke: Claude + Codex reach hook install.
+
+    Python/package installation is stubbed so the test is deterministic and
+    offline; the assertion is on the actual hook command the JS wrapper invokes.
+    """
+    fake_bin = tmp_path / "bin"
+    fake_bin.mkdir()
+    calls = tmp_path / "calls.jsonl"
+
+    _write_executable(
+        fake_bin / "python3",
+        """#!/bin/sh
+printf '%s\n' "python3 $*" >> "$GRADATA_INSTALL_SMOKE_CALLS"
+if [ "$*" = "--version" ]; then
+  printf '%s\n' "Python 3.11.9"
+fi
+exit 0
+""",
+    )
+    _write_executable(
+        fake_bin / "gradata",
+        """#!/bin/sh
+printf '%s\n' "gradata $*" >> "$GRADATA_INSTALL_SMOKE_CALLS"
+exit 0
+""",
+    )
+
+    env = os.environ.copy()
+    env.update(
+        {
+            "HOME": str(tmp_path / "home"),
+            "USERPROFILE": str(tmp_path / "home"),
+            "PATH": str(fake_bin),
+            "GRADATA_INSTALL_SMOKE_CALLS": str(calls),
+        }
+    )
+
+    result = subprocess.run(
+        [shutil.which("node") or "node", str(INSTALLER_JS), "install", "--ide", ide],
+        cwd=REPO_ROOT,
+        env=env,
+        text=True,
+        capture_output=True,
+        check=False,
+    )
+
+    assert result.returncode == 0, result.stderr or result.stdout
+    assert f"[gradata-install] Target IDE: {ide}" in result.stdout
+    recorded = calls.read_text(encoding="utf-8").splitlines()
+    assert "gradata " + " ".join(expected_hook_args) in recorded
+
+
+def _write_executable(path: Path, text: str) -> None:
+    path.write_text(text, encoding="utf-8")
+    path.chmod(0o755)