diff --git a/graphify/__main__.py b/graphify/__main__.py
index 6d2545bcd..fa453e971 100644
--- a/graphify/__main__.py
+++ b/graphify/__main__.py
@@ -861,7 +861,11 @@ def _run_cli() -> None:
         print("Usage: graphify <command>")
         print()
         print("Commands:")
-        print("  install [--platform P]  copy skill to platform config dir (claude|windows|codebuddy|codex|opencode|aider|amp|agents|claw|droid|trae|trae-cn|gemini|cursor|antigravity|hermes|kiro|pi|devin|copilot|kilo|kimi)")
+        # Derive the list from the same source as `graphify install` usage
+        # (_print_install_usage) so the two can never drift apart, rather than
+        # hand-maintaining it (amp, copilot, antigravity-windows had been missed, #4655).
+        _platform_values = "|".join([*_PLATFORM_CONFIG, "gemini", "cursor"])
+        print(f"  install [--platform P]  copy skill to platform config dir ({_platform_values})")
         print("  uninstall               remove graphify from all detected platforms in one shot")
         print("    --purge                 also delete graphify-out/ directory")
         print("  path \"A\" \"B\"            shortest path between two nodes in graph.json")
diff --git a/tests/test_cli_help.py b/tests/test_cli_help.py
index 49d73cdb1..93c60d486 100644
--- a/tests/test_cli_help.py
+++ b/tests/test_cli_help.py
@@ -39,3 +39,28 @@ def test_help_lists_prs_provider_and_export_formats():
     # Silent hook internals — deliberately excluded from user-facing help.
     assert "hook-check" not in out
     assert "hook-guard" not in out
+
+
+def test_help_lists_every_install_platform():
+    """#4655: the `install [--platform P]` line must advertise every accepted
+    `--platform` value. It is derived from the same source as `graphify install`
+    usage (`[*_PLATFORM_CONFIG, "gemini", "cursor"]`), so this guards against the
+    list silently drifting again (amp, copilot, kilo, kimi, antigravity-windows
+    had all gone missing)."""
+    import re
+
+    from graphify.install import _PLATFORM_CONFIG
+
+    r = subprocess.run(
+        [PYTHON, "-m", "graphify", "--help"],
+        capture_output=True,
+        text=True,
+    )
+    assert r.returncode == 0, f"--help should exit 0: {r.stderr}"
+    m = re.search(r"install \[--platform P\][^(]*\(([^)]*)\)", r.stdout)
+    assert m, "could not find the install --platform list in `graphify --help`"
+    listed = set(m.group(1).split("|"))
+    for platform_name in [*_PLATFORM_CONFIG, "gemini", "cursor"]:
+        assert platform_name in listed, (
+            f"`graphify --help` must list the --platform value {platform_name!r} (#4655)"
+        )