slack: slim down the trace reply (drop greeting, suppress unfurl) (#1278)

Now that assistant.threads.setStatus carries the "is thinking…"
indicator, the per-run greeting phrase + auto-unfurl on the LangSmith
link are just visual noise stacking on top of it. The trace reply now
posts only `<url|View trace>` + a tip, with link unfurling off so the
smith.langchain.com card no longer appears.

Adds an `unfurl_links`/`unfurl_media` knob to post_slack_thread_reply_with_ts
(default-on to preserve behaviour for every other caller).

agent/utils/slack.py

@@ -334,15 +334,24 @@ async def set_slack_assistant_status(
             return False
 
 
-async def post_slack_thread_reply_with_ts(channel_id: str, thread_ts: str, text: str) -> str | None:
+async def post_slack_thread_reply_with_ts(
+    channel_id: str,
+    thread_ts: str,
+    text: str,
+    *,
+    unfurl_links: bool = True,
+    unfurl_media: bool = True,
+) -> str | None:
     """Post a reply in a Slack thread and return its Slack timestamp."""
     if not SLACK_BOT_TOKEN:
         return None
 
-    payload = {
+    payload: dict[str, Any] = {
         "channel": channel_id,
         "thread_ts": thread_ts,
         "text": text,
+        "unfurl_links": unfurl_links,
+        "unfurl_media": unfurl_media,
     }
 
     async with httpx.AsyncClient() as http_client:
@@ -682,19 +691,6 @@ async def resolve_slack_links_in_context(
     return resolved_links_section, image_urls
 
 
-TRACE_REPLY_PHRASES: tuple[str, ...] = (
-    "Working on it!",
-    "On it!",
-    "Diving in!",
-    "Powering up!",
-    "Heads down.",
-    "Cracking knuckles...",
-    "Spinning up...",
-    "Looking...",
-    "Time to cook. 🧑‍🍳",
-    "Running to the roar!",
-)
-
 TRACE_REPLY_TIPS: tuple[str, ...] = (
     "You can message me in this thread while I'm running — I'll pick up your follow-up before my next step.",
     "Kick off another task in parallel — each one runs in its own isolated sandbox, no queuing.",
@@ -707,22 +703,22 @@ TRACE_REPLY_TIPS: tuple[str, ...] = (
 )
 
 
-def _format_trace_reply(message: str, trace_url: str | None) -> str:
+def _format_trace_reply(trace_url: str | None) -> str:
     """Format the initial trace reply with a randomly selected tip."""
     tip = random.choice(TRACE_REPLY_TIPS)
-    head = f"{message} <{trace_url}|View trace>" if trace_url else message
+    head = f"<{trace_url}|View trace>\n" if trace_url else ""
-    return f"{head}\n_Tip: {tip}_"
+    return f"{head}_Tip: {tip}_"
 
 
-async def post_slack_trace_reply(
+async def post_slack_trace_reply(channel_id: str, thread_ts: str, thread_id: str) -> str | None:
-    channel_id: str, thread_ts: str, thread_id: str, message: str | None = None
-) -> str | None:
     """Post a trace URL reply in a Slack thread and return its Slack timestamp."""
-    if message is None:
-        message = random.choice(TRACE_REPLY_PHRASES)
     trace_url = get_langsmith_trace_url(thread_id)
     return await post_slack_thread_reply_with_ts(
-        channel_id, thread_ts, _format_trace_reply(message, trace_url)
+        channel_id,
+        thread_ts,
+        _format_trace_reply(trace_url),
+        unfurl_links=False,
+        unfurl_media=False,
     )
 
 

agent/webapp.py

@@ -1021,9 +1021,7 @@ async def process_slack_pr_review_request(
     if result.get("success"):
         thread_id = result.get("thread_id")
         if isinstance(thread_id, str) and thread_id:
-            await post_slack_trace_reply(
+            await post_slack_trace_reply(channel_id, thread_ts, thread_id)
-                channel_id, thread_ts, thread_id, message="Taking a look..."
-            )
             await set_slack_assistant_status(channel_id, thread_ts)
         return
 

tests/test_github_issue_webhook.py

@@ -603,14 +603,11 @@ def test_process_slack_pr_review_request_posts_trace_reply(monkeypatch) -> None:
         captured["slack_thread_ts"] = slack_thread_ts
         return {"success": True, "thread_id": "reviewer-thread-id", "pr_url": pr_ref.url}
 
-    async def fake_post_slack_trace_reply(
+    async def fake_post_slack_trace_reply(channel_id: str, thread_ts: str, thread_id: str) -> None:
-        channel_id: str, thread_ts: str, thread_id: str, message: str = "Working on it!"
-    ) -> None:
         captured["trace_reply"] = {
             "channel_id": channel_id,
             "thread_ts": thread_ts,
             "thread_id": thread_id,
-            "message": message,
         }
 
     async def fake_set_slack_assistant_status(channel_id: str, thread_ts: str) -> bool:
@@ -641,7 +638,6 @@ def test_process_slack_pr_review_request_posts_trace_reply(monkeypatch) -> None:
         "channel_id": "C123",
         "thread_ts": "1700000000.000100",
         "thread_id": "reviewer-thread-id",
-        "message": "Taking a look...",
     }
     assert captured["status_calls"] == [
         ("C123", "1700000000.000100"),

tests/test_slack_context.py

@@ -5,7 +5,6 @@ import pytest
 from agent import webapp
 from agent.utils import slack as slack_utils
 from agent.utils.slack import (
-    TRACE_REPLY_PHRASES,
     TRACE_REPLY_TIPS,
     convert_mentions_to_slack_format,
     format_slack_messages_for_prompt,
@@ -222,15 +221,20 @@ def test_format_slack_messages_for_prompt_replaces_bot_id_mention_in_text() -> N
     assert formatted == "@alice(U123): @open-swe status update?"
 
 
-def test_post_slack_trace_reply_picks_random_phrase_when_no_message(
+def test_post_slack_trace_reply_emits_tip_only_when_no_trace_url(
     monkeypatch: pytest.MonkeyPatch,
 ) -> None:
-    posted: list[str] = []
+    posted: list[dict] = []
 
     async def fake_post_slack_thread_reply_with_ts(
-        channel_id: str, thread_ts: str, text: str
+        channel_id: str,
+        thread_ts: str,
+        text: str,
+        *,
+        unfurl_links: bool = True,
+        unfurl_media: bool = True,
     ) -> str | None:
-        posted.append(text)
+        posted.append({"text": text, "unfurl_links": unfurl_links, "unfurl_media": unfurl_media})
         return "1.1"
 
     monkeypatch.setattr(
@@ -241,35 +245,44 @@ def test_post_slack_trace_reply_picks_random_phrase_when_no_message(
     asyncio.run(post_slack_trace_reply("C123", "1.0", "thread-id"))
 
     assert len(posted) == 1
-    head, _, tip_line = posted[0].partition("\n")
+    text = posted[0]["text"]
-    assert head in TRACE_REPLY_PHRASES
+    assert text.startswith("_Tip: ") and text.endswith("_")
-    assert tip_line.startswith("_Tip: ") and tip_line.endswith("_")
+    assert any(tip in text for tip in TRACE_REPLY_TIPS)
-    assert any(tip in tip_line for tip in TRACE_REPLY_TIPS)
+    assert posted[0]["unfurl_links"] is False
+    assert posted[0]["unfurl_media"] is False
 
 
-def test_post_slack_trace_reply_uses_explicit_message_when_provided(
+def test_post_slack_trace_reply_includes_trace_link_and_tip(
     monkeypatch: pytest.MonkeyPatch,
 ) -> None:
-    posted: list[str] = []
+    posted: list[dict] = []
 
     async def fake_post_slack_thread_reply_with_ts(
-        channel_id: str, thread_ts: str, text: str
+        channel_id: str,
+        thread_ts: str,
+        text: str,
+        *,
+        unfurl_links: bool = True,
+        unfurl_media: bool = True,
     ) -> str | None:
-        posted.append(text)
+        posted.append({"text": text, "unfurl_links": unfurl_links, "unfurl_media": unfurl_media})
         return "1.1"
 
     monkeypatch.setattr(
         slack_utils, "post_slack_thread_reply_with_ts", fake_post_slack_thread_reply_with_ts
     )
-    monkeypatch.setattr(slack_utils, "get_langsmith_trace_url", lambda thread_id: None)
+    monkeypatch.setattr(slack_utils, "get_langsmith_trace_url", lambda thread_id: "https://smith/x")
 
-    asyncio.run(post_slack_trace_reply("C123", "1.0", "thread-id", message="Taking a look..."))
+    asyncio.run(post_slack_trace_reply("C123", "1.0", "thread-id"))
 
     assert len(posted) == 1
-    head, _, tip_line = posted[0].partition("\n")
+    text = posted[0]["text"]
-    assert head == "Taking a look..."
+    head, _, tip_line = text.partition("\n")
+    assert head == "<https://smith/x|View trace>"
     assert tip_line.startswith("_Tip: ") and tip_line.endswith("_")
     assert any(tip in tip_line for tip in TRACE_REPLY_TIPS)
+    assert posted[0]["unfurl_links"] is False
+    assert posted[0]["unfurl_media"] is False
 
 
 def test_select_slack_context_messages_detects_username_mention() -> None:
@@ -516,14 +529,11 @@ def _setup_slack_mention_fakes(
         captured["active_thread_id"] = thread_id
         return False
 
-    async def fake_post_slack_trace_reply(
+    async def fake_post_slack_trace_reply(channel_id: str, thread_ts: str, thread_id: str) -> None:
-        channel_id: str, thread_ts: str, thread_id: str, message: str | None = None
-    ) -> None:
         captured["trace_reply"] = {
             "channel_id": channel_id,
             "thread_ts": thread_ts,
             "thread_id": thread_id,
-            "message": message,
         }
 
     class _FakeRunsClient:
@@ -597,7 +607,6 @@ def test_process_slack_mention_creates_thread_first_run_with_trace_reply(
         "channel_id": "C123",
         "thread_ts": thread_ts,
         "thread_id": expected_thread_id,
-        "message": None,
     }
 
     run_create = captured["run_create"]