feat(honcho): explain why when honcho_profile returns an empty card

Closed PR #5137 addressed the retrieval path (peer cards via get_card()
instead of the session-scoped lookup that returned empty for per-session
messaging flows) — that architectural fix is already in main as
_fetch_peer_card / _fetch_peer_context.

What never got fixed is the user-visible side: honcho_profile returning
a flat 'No profile facts available yet.' leaves the model to guess at
why.  The model then often surfaces it to the user as a cryptic error.

Adds a diagnostic hint next to the existing 'result' message, enumerating
the likely causes in rough order of frequency:

  1. Observation disabled for this peer (user_observe_me/others off)
  2. Peer card hasn't accumulated yet (fresh peer / dialectic cadence
     hasn't fired enough turns — cards build over time)
  3. Generic fallback: self-hosted Honcho < 3.x lacks peer cards

The hint also suggests alternative tools (honcho_reasoning / honcho_search)
so the model can route around the empty card rather than giving up.

Schema description updated so the model knows the hint field exists and
that an empty card is NOT an error state.

7 tests cover the hint paths: warmup, observation-disabled for user + ai,
generic fallback, populated card still returns plain result (no hint),
alternative-tool suggestion present.

tests/honcho_plugin/test_empty_profile_hint.py

@@ -0,0 +1,85 @@
+"""Tests for honcho_profile's empty-card hint (#5137 follow-up)."""
+
+from __future__ import annotations
+
+import json
+from unittest.mock import MagicMock
+
+from plugins.memory.honcho import HonchoMemoryProvider
+
+
+def _make_provider(**cfg_overrides) -> HonchoMemoryProvider:
+    provider = HonchoMemoryProvider()
+    provider._manager = MagicMock()
+    provider._manager.get_peer_card.return_value = []  # empty card
+    provider._session_key = "agent:main:test"
+    provider._session_initialized = True  # bypass the lazy _ensure_session() gate
+    provider._cron_skipped = False
+
+    cfg = MagicMock()
+    # Defaults match HonchoClientConfig defaults
+    cfg.user_observe_me = cfg_overrides.get("user_observe_me", True)
+    cfg.user_observe_others = cfg_overrides.get("user_observe_others", True)
+    cfg.ai_observe_me = cfg_overrides.get("ai_observe_me", True)
+    cfg.ai_observe_others = cfg_overrides.get("ai_observe_others", True)
+    cfg.message_max_chars = 25000
+    provider._config = cfg
+
+    provider._dialectic_cadence = cfg_overrides.get("dialectic_cadence", 1)
+    provider._turn_count = cfg_overrides.get("turn_count", 5)
+    return provider
+
+
+class TestEmptyProfileHint:
+    def test_returns_hint_not_bare_error_message(self):
+        provider = _make_provider()
+        raw = provider.handle_tool_call("honcho_profile", {})
+        payload = json.loads(raw)
+        assert payload["result"] == "No profile facts available yet."
+        assert "hint" in payload
+        assert "not an error" in payload["hint"].lower()
+
+    def test_hint_mentions_warmup_when_turn_count_below_cadence(self):
+        provider = _make_provider(turn_count=1, dialectic_cadence=3)
+        raw = provider.handle_tool_call("honcho_profile", {})
+        payload = json.loads(raw)
+        assert "turn" in payload["hint"].lower()
+        assert "cadence" in payload["hint"].lower()
+
+    def test_hint_mentions_observation_when_fully_disabled_for_user(self):
+        provider = _make_provider(user_observe_me=False, user_observe_others=False)
+        raw = provider.handle_tool_call("honcho_profile", {"peer": "user"})
+        payload = json.loads(raw)
+        assert "observation is disabled" in payload["hint"].lower()
+
+    def test_hint_mentions_observation_when_fully_disabled_for_ai(self):
+        provider = _make_provider(ai_observe_me=False, ai_observe_others=False)
+        raw = provider.handle_tool_call("honcho_profile", {"peer": "ai"})
+        payload = json.loads(raw)
+        assert "observation is disabled" in payload["hint"].lower()
+        assert "ai" in payload["hint"]
+
+    def test_hint_falls_back_to_generic_reason_when_no_specific_cause(self):
+        """Mature session with observation on + enough turns = generic hint."""
+        provider = _make_provider(turn_count=50, dialectic_cadence=1)
+        raw = provider.handle_tool_call("honcho_profile", {})
+        payload = json.loads(raw)
+        assert "hint" in payload
+        # Generic hint mentions self-hosted as a common cause
+        assert any(word in payload["hint"].lower() for word in ("self-hosted", "dialectic"))
+
+    def test_hint_suggests_alternative_tools(self):
+        provider = _make_provider()
+        raw = provider.handle_tool_call("honcho_profile", {})
+        payload = json.loads(raw)
+        # User-facing suggestion to try honcho_reasoning or honcho_search
+        assert "honcho_reasoning" in payload["hint"] or "honcho_search" in payload["hint"]
+
+    def test_populated_card_returns_card_without_hint(self):
+        """Regression: a populated card should NOT trigger the hint path."""
+        provider = _make_provider()
+        provider._manager.get_peer_card.return_value = ["Fact 1", "Fact 2"]
+        raw = provider.handle_tool_call("honcho_profile", {})
+        payload = json.loads(raw)
+        assert payload["result"] == ["Fact 1", "Fact 2"]
+        assert "hint" not in payload