fix(agentex): Slack gateway — empty ack body + clearer breadcrumb attribution

agentex/openapi.yaml

@@ -2563,10 +2563,7 @@ paths:
           description: Successful Response
           content:
             application/json:
-              schema:
-                additionalProperties: true
-                type: object
-                title: Response Slack Commands Slack Commands Post
+              schema: {}
   /slack/interactions:
     post:
       tags:
@@ -2578,10 +2575,7 @@ paths:
           description: Successful Response
           content:
             application/json:
-              schema:
-                additionalProperties: true
-                type: object
-                title: Response Slack Interactions Slack Interactions Post
+              schema: {}
   /tracker/{tracker_id}:
     get:
       tags:

agentex/src/api/routes/slack.py

@@ -6,13 +6,22 @@
 secrets microservice. Delegates all logic to SlackGatewayUseCase.
 """
 
-from fastapi import APIRouter, BackgroundTasks, Request
+from fastapi import APIRouter, BackgroundTasks, Request, Response
+from fastapi.responses import JSONResponse
 
 from src.domain.use_cases.slack_gateway_use_case import DSlackGatewayUseCase
 
 router = APIRouter(prefix="/slack", tags=["Slack"])
 
 
+def _slack_ack(result: dict) -> Response:
+    """Serialize a slash-command / interaction response for Slack. An ack-only result
+    (empty dict) becomes a truly EMPTY 200 body — Slack renders a bare ``{}`` JSON body
+    as a stray message, so "show nothing" must send no body, not ``{}``. A non-empty
+    result (ephemeral message / response_action) is sent as JSON."""
+    return JSONResponse(result) if result else Response(status_code=200)
+
+
 @router.post("/events", summary="Slack Events API ingress for the @agent app")
 async def slack_events(
     request: Request,
@@ -31,26 +40,30 @@ async def slack_events(
 async def slack_commands(
     request: Request,
     use_case: DSlackGatewayUseCase,
-) -> dict:
+) -> Response:
     # Slash commands are application/x-www-form-urlencoded, not JSON. Read the raw
     # body first (needed for signature verification), then parse the form.
     body = await request.body()
     form = dict(await request.form())
     headers = {k.lower(): v for k, v in request.headers.items()}
-    return await use_case.handle_slash_command(body=body, headers=headers, form=form)
+    return _slack_ack(
+        await use_case.handle_slash_command(body=body, headers=headers, form=form)
+    )
 
 
 @router.post("/interactions", summary="Slack interactivity ingress (modals, shortcuts)")
 async def slack_interactions(
     request: Request,
     background: BackgroundTasks,
     use_case: DSlackGatewayUseCase,
-) -> dict:
+) -> Response:
     # Interactions are form-encoded with a JSON `payload` field. Raw body first (for
     # signature verification), then the form. The turn runs out-of-band like events.
     body = await request.body()
     form = dict(await request.form())
     headers = {k.lower(): v for k, v in request.headers.items()}
-    return await use_case.handle_interaction(
-        body=body, headers=headers, form=form, background=background
+    return _slack_ack(
+        await use_case.handle_interaction(
+            body=body, headers=headers, form=form, background=background
+        )
     )

agentex/src/domain/use_cases/slack_gateway_use_case.py

@@ -531,7 +531,7 @@ async def _submit_agents_modal(
                         "elements": [
                             {
                                 "type": "mrkdwn",
-                                "text": f"via <@{user}> through *{agent}*",
+                                "text": f"<@{user}> asked *{agent}*",
                             }
                         ],
                     },

agentex/tests/unit/api/test_slack_routes.py

@@ -0,0 +1,23 @@
+"""Slack route ack helper: an ack-only result (empty dict) must be a TRULY EMPTY 200
+body — Slack renders a bare ``{}`` JSON body as a stray message, so "show nothing" has
+to send no body, not ``{}``. A non-empty result is sent as JSON."""
+
+import json
+
+import pytest
+from fastapi.responses import JSONResponse
+from src.api.routes.slack import _slack_ack
+
+
+@pytest.mark.unit
+class TestSlackAck:
+    def test_empty_result_is_empty_200_body(self):
+        resp = _slack_ack({})
+        assert resp.status_code == 200
+        assert resp.body == b""  # not b"{}" — nothing for Slack to render
+
+    def test_non_empty_result_is_json(self):
+        payload = {"response_type": "ephemeral", "text": "hi"}
+        resp = _slack_ack(payload)
+        assert isinstance(resp, JSONResponse)
+        assert json.loads(resp.body) == payload