feat(content): universal anti-soup guard on every agent free-text field

tests/unit/gateway/test_content_actions.py

@@ -678,7 +678,7 @@ async def test_notify_explicit_task_not_found_rejected() -> None:
     env = await ca.notify(
         agent_id=agent_id,
         target="be-dev-1",
-        text="hi",
+        text="Please review the assembled PR before merge.",
         priority="normal",
         task_id=uuid4(),
     )
@@ -803,7 +803,10 @@ async def test_progress_unknown_plan_step_invalid_state_lists_valid() -> None:
     actions = ContentActions(_make_deps(task=task))
 
     env = await actions.progress(
-        agent_id=agent_id, task_id=t.id, message="?", plan_step="bogus"
+        agent_id=agent_id,
+        task_id=t.id,
+        message="Finished the auth refactor step.",
+        plan_step="bogus",
     )
     body = env.as_dict()
     assert body["error"] == "invalid_state", body

tests/unit/gateway/test_content_soup_guard.py

@@ -0,0 +1,37 @@
+"""Universal anti-soup guard — no filler/placeholder text in ANY agent field.
+
+``ContentActions._reject_soup`` is applied to every free-text content tool
+(say/dm/note/progress/notify/pitch) so soup lands nowhere. It returns a
+remediation Envelope (never a raw 422 — that trips the do-server circuit
+breaker), or None when the text is substantive.
+"""
+
+from __future__ import annotations
+
+import pytest
+from roboco.services.gateway.content_actions import ContentActions
+
+_guard = ContentActions._reject_soup
+
+
+@pytest.mark.parametrize("soup", ["", "   ", "asdf", "...", "wip", "tbd", "x", "-"])
+def test_rejects_placeholders_and_filler(soup: str) -> None:
+    assert _guard(soup, field="message", min_chars=2) is not None
+
+
+def test_accepts_substantive_text() -> None:
+    assert _guard("LGTM — merging after CI.", field="message", min_chars=2) is None
+    assert _guard("ok", field="message", min_chars=2) is None  # terse but real
+
+
+def test_min_chars_enforced_per_field() -> None:
+    # A note must be a sentence, not a fragment.
+    assert _guard("hi", field="note", min_chars=8) is not None
+    assert _guard("Reviewed the auth refactor.", field="note", min_chars=8) is None
+
+
+def test_returns_remediation_envelope() -> None:
+    env = _guard("asdf", field="progress update", min_chars=5)
+    assert env is not None
+    assert env.error is not None
+    assert "progress update" in (env.remediate or "")