refactor(systems): one seam — the Systems question rides every read and write of a record

Scribe issue #2570, from the operator's challenge: the invariant is
"always be asking whether what you're touching is a System's territory
and whether the work is filed there" — not a nudge in one corner. The
prior shape failed it twice: the hint fired only on creates (with a
special-cased zero-Systems branch), and get_task/get_note returned
records WITHOUT their Systems, so the read-side reflex had nothing to
fire on (same per-kind asymmetry as #2481).

- attach_systems(): single helper used by get/create/update for tasks,
  notes, and snippets, plus add_task_log. Tagged records always show
  `systems`; an untagged project record carries the `systems_hint`
  question instead. Neither field attaches empty (#2483). Hint is
  owner-only; everything fail-open (#2109).
- untagged_systems_hint unified to ONE question — the vocabulary
  listing varies, the question doesn't; the zero-Systems branch stops
  being special text.
- Docstrings state the uniform contract; floor prose now names the
  read-side reflex (systems visible -> list_system_records the pile).
- Plugin 0.1.27 -> 0.1.28.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/scribe/mcp/tools/systems.py

@@ -17,40 +17,68 @@ from scribe.services import systems as systems_svc
 
 
 async def untagged_systems_hint(user_id: int, project_id: int) -> str | None:
-    """Nudge text for a record created untagged in a project that has Systems.
+    """The Systems question, for an untagged project record.
 
-    Not a tool. create_task / create_note / create_snippet attach this to
-    their responses so the tagging question arrives in-band at the exact write
-    it applies to — instruction prose alone demonstrably doesn't fire at write
-    time, while in-band behavior (the duplicate gate) does (#2562).
+    Not a tool — attach_systems() rides this on tool responses so the question
+    arrives in-band at the exact moment a record is touched. It is ONE
+    question regardless of vocabulary state ("which area is this about, and is
+    it modelled?"); only the vocabulary listing varies, because an empty
+    vocabulary is not an exemption — it is the question at its most urgent
+    (#2562, #2569). Instruction prose alone demonstrably doesn't fire at write
+    time; in-band behavior (the duplicate gate) does.
     """
-    # Fail-open like the dedup gate: a hint must never break a create.
+    # Fail-open like the dedup gate: a hint must never break the call.
     try:
         systems = await systems_svc.list_systems(user_id, project_id)
     except Exception:
         return None
-    if not systems:
-        # Zero Systems is the one state nothing else nudges out of: the hint
-        # below needs a vocabulary to name, so without this branch the FIRST
-        # create_system depends entirely on prose that demonstrably doesn't
-        # fire at write time (#2562).
-        return (
-            "Created untagged — this project has no Systems yet. If this "
-            "record is about a code subsystem/area, create_system it (name + "
-            "a one-paragraph charter) and tag the record. An audit or sweep "
-            "that names areas is exactly the moment to mint them; the "
-            "duplicate gate is what guards against sprawl, not holding back."
-        )
-    names = ", ".join(f"#{s.id} {s.name}" for s in systems)
+    if systems:
+        vocab = "Existing Systems: " + ", ".join(
+            f"#{s.id} {s.name}" for s in systems
+        ) + "."
+    else:
+        vocab = "This project has no Systems yet."
     return (
-        f"Created untagged. This project's Systems: {names}. If this record is "
-        "about one or more of those areas, tag it (update it with "
-        "system_ids=[...]) — cross-cutting records like audits take several; "
-        "if an area it names is missing, create_system it and tag; only leave "
-        "it untagged if it is about no particular area."
+        "This record is untagged — which area(s) of the project is it about? "
+        f"{vocab} Tag it (system_ids=[...]) — cross-cutting records like "
+        "audits take several; create_system any area it concerns that isn't "
+        "modelled yet (a sweep that names areas is the moment to mint them, "
+        "and the duplicate gate guards against sprawl). Leave it untagged "
+        "only if it is genuinely about no particular area."
     )
 
 
+async def attach_systems(
+    caller_id: int,
+    owner_id: int,
+    data: dict,
+    note_id: int,
+    project_id: int | None,
+) -> None:
+    """Attach a record's Systems to its payload — or the Systems question.
+
+    ONE seam for every tool that returns a project record, read or write: a
+    tagged record shows its areas (the touching-a-System reflex needs the
+    affiliation visible on read, not just settable on write), an untagged
+    project record carries the question instead. Neither field is ever
+    attached empty (same reasoning as notes._attach_supersession / #2483 — a
+    field that always says nothing trains readers to skip fields). The hint
+    goes only to the record's owner: tagging someone else's record in someone
+    else's project is not the caller's call to make. Fail-open — decoration
+    must never break the call it rides on.
+    """
+    try:
+        systems = await systems_svc.list_record_systems(owner_id, note_id)
+        if systems:
+            data["systems"] = [s.to_dict() for s in systems]
+        elif project_id and caller_id == owner_id:
+            hint = await untagged_systems_hint(owner_id, project_id)
+            if hint:
+                data["systems_hint"] = hint
+    except Exception:
+        pass
+
+
 async def create_system(
     project_id: int,
     name: str,