diff --git a/agent/utils/slack.py b/agent/utils/slack.py
index 2439e05f..04134a53 100644
--- a/agent/utils/slack.py
+++ b/agent/utils/slack.py
@@ -444,57 +444,6 @@ async def post_slack_thread_reply(channel_id: str, thread_ts: str, text: str) ->
     return message_ts is not None
 
 
-async def post_slack_top_level_message_with_ts(
-    channel_id: str,
-    text: str,
-    *,
-    unfurl_links: bool = True,
-    unfurl_media: bool = True,
-    blocks: list[dict[str, Any]] | None = None,
-) -> tuple[str | None, str | None]:
-    """Post a fresh top-level message to a channel and return its ts and error."""
-    if not SLACK_BOT_TOKEN:
-        return None, "missing_slack_bot_token"
-
-    payload: dict[str, Any] = {
-        "channel": channel_id,
-        "text": text,
-        "unfurl_links": unfurl_links,
-        "unfurl_media": unfurl_media,
-    }
-    if blocks:
-        payload["blocks"] = blocks
-
-    async with httpx.AsyncClient() as http_client:
-        try:
-            response = await http_client.post(
-                f"{SLACK_API_BASE_URL}/chat.postMessage",
-                headers=_slack_headers(),
-                json=payload,
-            )
-            if response.status_code == 429:
-                retry_after = response.headers.get("Retry-After")
-                logger.warning("Slack chat.postMessage rate limited (retry-after=%s)", retry_after)
-                if retry_after:
-                    return None, f"rate_limited: {retry_after}"
-                return None, "rate_limited"
-            response.raise_for_status()
-            data = response.json()
-            if not data.get("ok"):
-                error = data.get("error")
-                logger.warning("Slack chat.postMessage failed: %s", error)
-                if error == "ratelimited":
-                    return None, "rate_limited"
-                return None, error
-            message_ts = data.get("ts")
-            if isinstance(message_ts, str) and message_ts:
-                return message_ts, None
-            return None, None
-        except httpx.HTTPError as exc:
-            logger.exception("Slack chat.postMessage request failed")
-            return None, f"http_error: {type(exc).__name__}"
-
-
 async def post_slack_ephemeral_message(
     channel_id: str, user_id: str, text: str, thread_ts: str | None = None
 ) -> bool:
diff --git a/tests/test_slack_thread_reply_tool.py b/tests/test_slack_thread_reply_tool.py
index df05327d..8fa1683e 100644
--- a/tests/test_slack_thread_reply_tool.py
+++ b/tests/test_slack_thread_reply_tool.py
@@ -175,16 +175,16 @@ def _channel_only_config() -> dict[str, Any]:
     return {"configurable": {"slack_thread": {"channel_id": "C9"}}}
 
 
-def test_slack_thread_reply_requires_channel_id(monkeypatch: pytest.MonkeyPatch) -> None:
+async def test_slack_thread_reply_requires_channel_id(monkeypatch: pytest.MonkeyPatch) -> None:
     monkeypatch.setattr(slack_reply_tool, "get_config", lambda: {"configurable": {}})
 
-    result = slack_reply_tool.slack_thread_reply("hello")
+    result = await slack_reply_tool.slack_thread_reply("hello")
 
     assert result["success"] is False
     assert result["error"] == "Missing slack_thread.channel_id in config"
 
 
-def test_slack_thread_reply_posts_top_level_when_no_thread_ts(
+async def test_slack_thread_reply_posts_top_level_when_no_thread_ts(
     monkeypatch: pytest.MonkeyPatch,
 ) -> None:
     captured: dict[str, Any] = {}
@@ -205,14 +205,14 @@ def test_slack_thread_reply_posts_top_level_when_no_thread_ts(
     monkeypatch.setattr(slack_reply_tool, "post_slack_top_level_message_with_ts", fake_top_level)
     monkeypatch.setattr(slack_reply_tool, "post_slack_thread_reply_with_ts", fail_thread_reply)
 
-    result = slack_reply_tool.slack_thread_reply("Scheduled report")
+    result = await slack_reply_tool.slack_thread_reply("Scheduled report")
 
     assert result == {"success": True}
     assert captured["channel_id"] == "C9"
     assert captured["text"] == "Scheduled report"
 
 
-def test_slack_thread_reply_top_level_surfaces_not_in_channel(
+async def test_slack_thread_reply_top_level_surfaces_not_in_channel(
     monkeypatch: pytest.MonkeyPatch,
 ) -> None:
     async def fake_top_level(
@@ -226,7 +226,7 @@ def test_slack_thread_reply_top_level_surfaces_not_in_channel(
     monkeypatch.setattr(slack_reply_tool, "get_config", _channel_only_config)
     monkeypatch.setattr(slack_reply_tool, "post_slack_top_level_message_with_ts", fake_top_level)
 
-    result = slack_reply_tool.slack_thread_reply("Scheduled report")
+    result = await slack_reply_tool.slack_thread_reply("Scheduled report")
 
     assert result["success"] is False
     assert result["slack_error"] == "not_in_channel"