diff --git a/tests/gateway/test_discord_sync_limit.py b/tests/gateway/test_discord_sync_limit.py
new file mode 100644
index 00000000000..ca8f298f80f
--- /dev/null
+++ b/tests/gateway/test_discord_sync_limit.py
@@ -0,0 +1,140 @@
+"""Test Discord slash command sync respects the 100-command hard limit."""
+
+from types import SimpleNamespace
+from unittest.mock import AsyncMock, MagicMock, patch
+import sys
+
+import pytest
+
+from gateway.config import PlatformConfig
+
+
+def _ensure_discord_mock():
+    if "discord" in sys.modules and hasattr(sys.modules["discord"], "__file__"):
+        return
+    if sys.modules.get("discord") is None:
+        discord_mod = MagicMock()
+        discord_mod.Intents.default.return_value = MagicMock()
+        sys.modules["discord"] = discord_mod
+        sys.modules["discord.ext"] = MagicMock()
+        sys.modules["discord.ext.commands"] = MagicMock()
+
+
+_ensure_discord_mock()
+
+from plugins.platforms.discord.adapter import DiscordAdapter
+
+
+class _FakeTreeCommand:
+    """Minimal command stub matching discord.py tree command API."""
+
+    def __init__(self, name: str, command_type: int = 1):
+        self.name = name
+        self.type = command_type
+
+    def to_dict(self, _tree):
+        return {"name": self.name, "type": self.type}
+
+
+@pytest.fixture
+def adapter():
+    """Create a Discord adapter with mocked Discord client."""
+    _ensure_discord_mock()
+    config = PlatformConfig(enabled=True, token="fake-token")
+    adapter = DiscordAdapter(config)
+
+    # Mock the Discord client and tree
+    adapter._client = MagicMock()
+    adapter._client.tree = MagicMock()
+    adapter._client.http = AsyncMock()
+    adapter._client.application_id = "test_app_id"
+
+    adapter._sleep_between_command_sync_mutations = AsyncMock()
+    adapter._existing_command_to_payload = MagicMock(side_effect=lambda cmd: {"name": cmd.name})
+    adapter._canonicalize_app_command_payload = MagicMock(side_effect=lambda p: p)
+    adapter._patchable_app_command_payload = MagicMock(side_effect=lambda p: p)
+
+    return adapter
+
+
+@pytest.mark.asyncio
+async def test_safe_sync_deletes_before_creating():
+    """Sync must delete obsolete commands BEFORE creating new ones.
+
+    Discord's 100-command limit is enforced when trying to upsert. If we
+    have 100 commands on Discord, try to add 1 new one, and haven't deleted
+    any yet, Discord rejects with error 30032.
+
+    The fix: identify and delete obsolete commands first, then create/update.
+    This ensures we never temporarily exceed 100 during the sync operation.
+
+    This is a regression guard for the samuraiheart bug where sync would fail
+    with error 30032 even though the registration code properly capped at 100.
+    """
+    _ensure_discord_mock()
+    config = PlatformConfig(enabled=True, token="fake-token")
+    adapter = DiscordAdapter(config)
+
+    adapter._client = MagicMock()
+    adapter._client.tree = MagicMock()
+    adapter._client.http = AsyncMock()
+    adapter._client.application_id = "test_app_id"
+    adapter._sleep_between_command_sync_mutations = AsyncMock()
+    adapter._existing_command_to_payload = MagicMock(side_effect=lambda cmd: {"name": cmd.name})
+    adapter._canonicalize_app_command_payload = MagicMock(side_effect=lambda p: p)
+    adapter._patchable_app_command_payload = MagicMock(side_effect=lambda p: p)
+
+    # Simulate having 100 commands on Discord, with 1 that's no longer desired
+    # and 1 new command that should be created.
+    # Existing on Discord: cmd_0, cmd_1, ..., cmd_99 (100 total)
+    # Desired locally: cmd_1, cmd_2, ..., cmd_99, cmd_new (100 total)
+    # So: delete cmd_0 (1 deletion), create cmd_new (1 creation)
+
+    existing_commands = [
+        SimpleNamespace(id=f"id_{i}", name=f"cmd_{i}", type=1)
+        for i in range(100)
+    ]
+    adapter._client.tree.fetch_commands = AsyncMock(return_value=existing_commands)
+
+    adapter._client.tree.get_commands = MagicMock(
+        return_value=[
+            _FakeTreeCommand(name=f"cmd_{i}", command_type=1)
+            for i in range(1, 100)
+        ] + [_FakeTreeCommand(name="cmd_new", command_type=1)]
+    )
+
+    # Track the order of mutations
+    mutation_log = []
+
+    async def mock_delete(*args):
+        mutation_log.append(("delete", args[-1]))
+
+    async def mock_upsert(*args):
+        mutation_log.append(("create", args[-1].get("name")))
+
+    adapter._client.http.delete_global_command = mock_delete
+    adapter._client.http.upsert_global_command = mock_upsert
+    adapter._client.http.edit_global_command = AsyncMock()
+
+    # Call sync
+    await adapter._safe_sync_slash_commands()
+
+    # Verify that:
+    # 1. A deletion happened (cmd_0)
+    # 2. It happened BEFORE any creation
+    # 3. The creation of cmd_new happened AFTER deletion
+    deletes = [m for m in mutation_log if m[0] == "delete"]
+    creates = [m for m in mutation_log if m[0] == "create"]
+
+    assert len(deletes) >= 1, "At least one command should be deleted"
+    assert len(creates) >= 1, "At least one command should be created"
+
+    # The key assertion: all deletions should come before all creations.
+    # Find the index of the last delete and the first create.
+    last_delete_idx = max(i for i, m in enumerate(mutation_log) if m[0] == "delete")
+    first_create_idx = min(i for i, m in enumerate(mutation_log) if m[0] == "create")
+
+    assert last_delete_idx < first_create_idx, (
+        f"Deletions must happen before creations to avoid exceeding 100-command limit. "
+        f"Last delete at index {last_delete_idx}, first create at index {first_create_idx}"
+    )