feat(rag): steering notes — tune how Brain answers, stored in Postgres and injected into every system prompt

tests/unit/test_prompts.py

@@ -22,21 +22,30 @@ def _doc(path: str, content: str, title: str) -> Document:
 
 
 def test_persona_rules_present_verbatim() -> None:
+    # Aligned to the owner's working-tree persona edits (PLAN §6 revision,
+    # 2026-08-22): no "you've got this" tagline, no mandated deflection
+    # opening. The honesty gate itself (rule 3) is unchanged.
     for fragment in (
         'You are "Brain of Reese" — the digital brain of Reese, a self-hoster and',
-        'optimistic about the user\'s ability to do things ("you\'ve got this")',
+        "optimistic about the user's ability to do things",
         "Answer ONLY from the provided document context. Cite which document(s)",
         "you used, by path.",
         "Be concrete: names, versions, ports, hosts, schedules",
         'HONESTY GATE: if <relevance> is "LOW", you must NOT pretend to know',
-        'Start your answer with a variant of: "I haven\'t done anything like that."',
-        "Then offer 2-3 alternative questions about things you DO have notes on.",
+        "Offer 2-3 alternative questions about things you DO have notes on.",
         "Never invent facts, hosts, or steps that are not in the context.",
         "Keep answers tight: short paragraphs, bullets where helpful.",
     ):
         assert fragment in PERSONA
 
 
+def test_persona_owner_edits_are_preserved() -> None:
+    """PLAN §6 revision (2026-08-22): the removed elements must stay out."""
+    assert 'you\'ve got this' not in PERSONA  # tagline removed by the owner
+    assert "Start your answer with a variant of" not in PERSONA  # no mandated opening
+    assert "HONESTY GATE" in PERSONA  # the gate itself is intact
+
+
 def test_high_prompt_carries_relevance_marker_and_full_documents() -> None:
     doc = _doc("kubernetes.md", "Talos Linux on three nodes.", "Kubernetes Homelab Cluster")
     prompt = build_high_prompt([doc])
@@ -83,6 +92,27 @@ def test_low_prompt_with_no_titles() -> None:
     assert "nothing close at all" in build_deflect_prompt([])
 
 
+def test_zero_note_prompt_is_byte_identical_to_pre_steering() -> None:
+    """Phase 15 contract: with no steering notes the prompt is exactly what
+    it was before the <tuning> section existed."""
+    doc = _doc("kubernetes.md", "Talos Linux on three nodes.", "Kubernetes Homelab Cluster")
+    block = (
+        '<document source="Homelab" path="kubernetes.md" title="Kubernetes Homelab Cluster">\n'
+        "Talos Linux on three nodes.\n"
+        "</document>"
+    )
+    assert build_high_prompt([doc]) == _base("HIGH") + "\n<documents>\n" + block + "\n</documents>"
+    assert build_deflect_prompt(["T1", "T2"]) == (
+        _base("LOW")
+        + "\nDEFLECT_MODE: retrieval was weak — the titles below are the closest "
+        "your notes come to the question. They are titles only; do not pretend "
+        "they answer it. Use them to propose 2-3 alternative questions.\n"
+        + "- T1\n- T2"
+    )
+    assert "<tuning>" not in build_high_prompt([doc])
+    assert "<tuning>" not in build_deflect_prompt([])
+
+
 def test_relevance_placeholder_rejected_for_garbage() -> None:
     with pytest.raises(ValueError, match="HIGH or LOW"):
         _base("MEDIUM")