feat(lessons): a lesson names the rule it is an instance of — lesson_rule_links (milestone 440 step 1, #4630)

The link between a lesson (one concrete situation) and the rule that governs
it, with the operator's soft-then-hard design built into its state:
suggested while evidence accumulates, confirmed or rejected once judged. Only
confirmed will carry a rule in retrieval (#4633); rejected is kept so the pair
is never proposed again.

- models/lesson_rule_link.py + migration 0111: one row per (lesson, rule),
  CASCADE on both ends, indexed both ways, CHECK on state (rule 36), evidence
  JSONB and judged_at.
- services/lesson_rules.py: require_rules (validated before any write, so
  a bad id leaves nothing half-linked), set_lesson_rules (set-semantics;
  a dropped rule becomes rejected, not forgotten), judge_link, and the two
  reads. ACL: write on the lesson (share-aware), ownership of the rule; a
  reader sees only rules they own. Decorations are fail-open (#4286).
- MCP: create_lesson / update_lesson take rule_ids; get/create/update return
  `rules`; new judge_lesson_link tool. REST: the same on /api/lessons plus
  PUT /api/lessons/<id>/rules/<rule_id>. Rules: rule_detail carries `lessons`.
- Backup v18: export (full and user-scoped, both ends in scope), builder,
  importer; both column guards register the table.
- Tests: integration (states, set-semantics, judge, ACL all-or-nothing,
  cascade both ways, CHECK, one row per pair); unit (door wiring, judge
  registered, migration/model state agreement, backup skip and unjudged
  stays unjudged). conftest stubs the decorations for unit tests.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

alembic/versions/0111_lesson_rule_links.py

@@ -0,0 +1,54 @@
+"""lesson_rule_links — a lesson points at the rule it is an instance of
+(milestone 440 step 1, #4196)
+
+Revision ID: 0111
+Revises: 0110
+Create Date: 2026-10-01
+
+One row per (lesson, rule) pair with a state: `suggested` while evidence
+accumulates, `confirmed` or `rejected` once a judgment is made. Only a
+confirmed link changes what surfaces; a rejected one is kept so the pair is not
+proposed again. CASCADE on both ends — a link to a record that no longer exists
+says nothing. No backfill: no lesson has ever been linked, and inventing a link
+would assert a judgment nobody made.
+"""
+import sqlalchemy as sa
+from sqlalchemy.dialects import postgresql
+from alembic import op
+
+revision = "0111"
+down_revision = "0110"
+branch_labels = None
+depends_on = None
+
+# One place, so the CHECK and the model's LINK_STATES cannot drift (rule 36:
+# a new value later means DROP + ADD CONSTRAINT in the same migration).
+_STATES = ("suggested", "confirmed", "rejected")
+
+
+def upgrade() -> None:
+    op.create_table(
+        "lesson_rule_links",
+        sa.Column("id", sa.BigInteger(), primary_key=True),
+        sa.Column("lesson_id", sa.Integer(), sa.ForeignKey("notes.id", ondelete="CASCADE"), nullable=False),
+        sa.Column("rule_id", sa.BigInteger(), sa.ForeignKey("rules.id", ondelete="CASCADE"), nullable=False),
+        sa.Column("state", sa.Text(), nullable=False, server_default="suggested"),
+        sa.Column("note", sa.Text(), nullable=True),
+        sa.Column("evidence", postgresql.JSONB(), nullable=True),
+        sa.Column("judged_at", sa.DateTime(timezone=True), nullable=True),
+        sa.Column("created_at", sa.DateTime(timezone=True), nullable=False, server_default=sa.text("now()")),
+        sa.UniqueConstraint("lesson_id", "rule_id", name="uq_lesson_rule_links_pair"),
+    )
+    op.create_check_constraint(
+        "ck_lesson_rule_links_state", "lesson_rule_links",
+        "state IN (" + ", ".join(f"'{s}'" for s in _STATES) + ")",
+    )
+    op.create_index("ix_lesson_rule_links_lesson_id", "lesson_rule_links", ["lesson_id"])
+    op.create_index("ix_lesson_rule_links_rule_id", "lesson_rule_links", ["rule_id"])
+
+
+def downgrade() -> None:
+    op.drop_index("ix_lesson_rule_links_rule_id", table_name="lesson_rule_links")
+    op.drop_index("ix_lesson_rule_links_lesson_id", table_name="lesson_rule_links")
+    op.drop_constraint("ck_lesson_rule_links_state", "lesson_rule_links", type_="check")
+    op.drop_table("lesson_rule_links")

src/scribe/mcp/tools/lessons.py

@@ -13,6 +13,7 @@ from scribe.mcp._context import current_user_id
 from scribe.services import access as access_svc
 from scribe.services import dedup as dedup_svc
 from scribe.services import knowledge as knowledge_svc
+from scribe.services import lesson_rules as lesson_rules_svc
 from scribe.services import lessons as lessons_svc
 from scribe.services import systems as systems_svc
 from scribe.services import trash as trash_svc
@@ -89,6 +90,7 @@ async def create_lesson(
     tags: list[str] | None = None,
     project_id: int = 0,
     system_ids: list[int] | None = None,
+    rule_ids: list[int] | None = None,
     force: bool = False,
 ) -> dict:
     """Record something you LEARNED, so a later session meets it at the moment
@@ -145,6 +147,12 @@ async def create_lesson(
             reach: a lesson is retrievable from every project (that is the
             point of the kind). 0 = none.
         system_ids: Systems (subsystems/areas) to file it under.
+        rule_ids: The rule(s) or preference(s) this lesson is an instance of —
+            the binding choice its situation falls under. A lesson never
+            becomes a rule; it points at the one that governs it, and the rule
+            is then reachable through the situation the lesson describes
+            (milestone 440). Naming a rule here confirms the link. Leave it
+            empty when no rule governs this situation.
         force: Create even if a near-duplicate exists.
 
     Returns the created lesson. On a near-duplicate, returns the existing id
@@ -161,6 +169,9 @@ async def create_lesson(
         )
 
     sources = lessons_svc.normalize_sources(learned_from)
+    # Validated before anything is written, so a lesson naming a rule the
+    # caller cannot read fails whole rather than saving half-linked.
+    linked = await lesson_rules_svc.require_rules(uid, rule_ids)
     title, body = lessons_svc.lesson_document(
         what, when_to_apply, insight, sources,
     )
@@ -179,8 +190,11 @@ async def create_lesson(
     )
     if system_ids:
         await systems_svc.set_record_systems(uid, note.id, system_ids)
+    if linked:
+        await lesson_rules_svc.set_lesson_rules(uid, note.id, linked)
     data = _to_dict(note)
     await systems_tools.attach_systems(uid, uid, data, note.id, project_id or None)
+    await lesson_rules_svc.attach_lesson_rules(uid, [data])
     return data
 
 
@@ -214,6 +228,7 @@ async def get_lesson(lesson_id: int, project_id: int = 0) -> dict:
     # one that was true when it asked — otherwise every first read of a lesson
     # reports a pull that is its own.
     await attach_usage([out])
+    await lesson_rules_svc.attach_lesson_rules(uid, [out])
     record_pulled(
         user_id=uid, note_id=int(note.id),
         source="mcp_get_lesson", project_id=project_id,
@@ -229,6 +244,7 @@ async def update_lesson(
     learned_from: list[int] | None = None,
     tags: list[str] | None = None,
     system_ids: list[int] | None = None,
+    rule_ids: list[int] | None = None,
 ) -> dict:
     """Update a lesson. Empty fields are left unchanged.
 
@@ -258,8 +274,16 @@ async def update_lesson(
             when that argument gets dropped (#4249). A System tag is how
             `list_system_records` gathers an area's pile, so an untagged
             lesson is reachable by search and by nothing else.
+        rule_ids: Replace the rule(s) this lesson is an instance of. None
+            leaves unchanged; pass the FULL list. A rule that was linked and
+            is left out is recorded as REJECTED — "not an instance of this
+            one" — so the pair is not proposed again; `[]` rejects them all.
     """
     uid = current_user_id()
+    linked = (
+        await lesson_rules_svc.require_rules(uid, rule_ids)
+        if rule_ids is not None else None
+    )
     note = await lessons_svc.update_lesson(
         uid, lesson_id,
         what=what or None,
@@ -276,7 +300,30 @@ async def update_lesson(
     if system_ids is not None:
         await systems_svc.set_record_systems(uid, lesson_id, system_ids)
         note = await lessons_svc.get_lesson(uid, lesson_id) or note
-    return _to_dict(note)
+    if linked is not None:
+        await lesson_rules_svc.set_lesson_rules(uid, lesson_id, linked)
+    out = _to_dict(note)
+    await lesson_rules_svc.attach_lesson_rules(uid, [out])
+    return out
+
+
+async def judge_lesson_link(
+    lesson_id: int, rule_id: int, verdict: str, note: str = "",
+) -> dict:
+    """Say whether a lesson is an instance of a rule: `verdict` is "confirm"
+    or "reject".
+
+    Reach for this when Scribe proposes a pair — a lesson and a rule that keep
+    arriving together in different situations — or whenever you are reading a
+    lesson and recognise the rule it falls under. Confirming makes the rule
+    reachable through the situation the lesson describes; rejecting records
+    that it is not, so the pair is not proposed again. `note` is the why, and
+    the next reader judges the link by it.
+
+    Returns the link: {lesson_id, rule_id, state, note, evidence, judged_at}.
+    """
+    uid = current_user_id()
+    return await lesson_rules_svc.judge_link(uid, lesson_id, rule_id, verdict, note)
 
 
 async def delete_lesson(lesson_id: int) -> dict:
@@ -312,5 +359,5 @@ async def delete_lesson(lesson_id: int) -> dict:
 
 def register(mcp) -> None:
     for fn in (list_lessons, create_lesson, get_lesson, update_lesson,
-               delete_lesson):
+               delete_lesson, judge_lesson_link):
         mcp.tool(name=fn.__name__)(fn)

src/scribe/models/__init__.py

@@ -77,6 +77,8 @@ from scribe.models.canonical_system import CanonicalSystem  # noqa: E402, F401
 from scribe.models.rulebook import (  # noqa: E402, F401
     Rulebook, RulebookTopic, Rule, RuleRelation, rule_systems,
 )
+# After notes and rules: it foreign-keys both (milestone 440).
+from scribe.models.lesson_rule_link import LessonRuleLink  # noqa: E402, F401
 from scribe.models.repo_binding import RepoBinding  # noqa: E402, F401
 from scribe.models.forge_connection import ForgeConnection  # noqa: E402, F401
 from scribe.models.code_shape import CodeShape, CodeShapeConsumer, CodeShapeEvent, CodeShapeUse  # noqa: E402, F401

src/scribe/models/lesson_rule_link.py

@@ -0,0 +1,77 @@
+from datetime import datetime
+
+from sqlalchemy import BigInteger, DateTime, ForeignKey, Integer, Text, UniqueConstraint
+from sqlalchemy.dialects.postgresql import JSONB
+from sqlalchemy.orm import Mapped, mapped_column
+
+from scribe.models import Base
+from scribe.models.base import CreatedAtMixin, iso
+
+SUGGESTED = "suggested"
+CONFIRMED = "confirmed"
+REJECTED = "rejected"
+# CHECK ck_lesson_rule_links_state (migration 0111, rule 36).
+LINK_STATES = (SUGGESTED, CONFIRMED, REJECTED)
+
+
+class LessonRuleLink(Base, CreatedAtMixin):
+    """A lesson says it is an instance of a rule (milestone 440, #4196).
+
+    A lesson records one concrete situation; a rule records the binding choice
+    for a class of them. The link lets the rule be reached through the
+    situations that keep proving it, and lets a situation with lessons and no
+    rule be noticed. A lesson never BECOMES a rule — it points at one.
+
+    ONE ROW PER PAIR, WITH A STATE, because the operator's design forms a link
+    in two stages ("a sort of soft and then hard link once it's been proven"):
+
+    - ``suggested`` — evidence is accumulating that the two belong together
+      (they keep arriving in the same request, in distinct situations). It
+      carries nothing in retrieval: a suggested link that brought its rule
+      along would manufacture the co-surfacing it counts, and prove itself.
+    - ``confirmed`` — a judgment said the lesson is an instance of the rule.
+      The only state that changes what surfaces.
+    - ``rejected`` — a judgment said it is not. Kept, evidence and all, so the
+      pair is never proposed again and the reason stays readable.
+
+    A table rather than a list on the lesson's `data`: the link needs a foreign
+    key on both ends (a deleted rule must not leave a lesson pointing at
+    nothing), a reverse index (a rule lists its lessons), and an id remap at
+    restore — none of which a JSON list gives.
+    """
+
+    __tablename__ = "lesson_rule_links"
+
+    id: Mapped[int] = mapped_column(BigInteger, primary_key=True)
+    lesson_id: Mapped[int] = mapped_column(
+        Integer, ForeignKey("notes.id", ondelete="CASCADE"), index=True,
+    )
+    rule_id: Mapped[int] = mapped_column(
+        BigInteger, ForeignKey("rules.id", ondelete="CASCADE"), index=True,
+    )
+    state: Mapped[str] = mapped_column(Text, default=SUGGESTED, server_default=SUGGESTED)
+    # Why it was confirmed or rejected — the reasoning a later reader needs to
+    # decide whether it still holds, as a rule relation's `note` is.
+    note: Mapped[str | None] = mapped_column(Text, nullable=True)
+    # What the suggestion rests on (filled by the co-surfacing recorder, #4637).
+    # Kept after a judgment so a confirmation can be read beside its evidence.
+    evidence: Mapped[dict | None] = mapped_column(JSONB, nullable=True)
+    # When a judgment moved it out of `suggested`. Null while suggested.
+    judged_at: Mapped[datetime | None] = mapped_column(
+        DateTime(timezone=True), nullable=True,
+    )
+
+    __table_args__ = (
+        UniqueConstraint("lesson_id", "rule_id", name="uq_lesson_rule_links_pair"),
+    )
+
+    def to_dict(self) -> dict:
+        return {
+            "lesson_id": self.lesson_id,
+            "rule_id": self.rule_id,
+            "state": self.state,
+            "note": self.note or "",
+            "evidence": self.evidence or {},
+            "judged_at": iso(self.judged_at),
+            "created_at": iso(self.created_at),
+        }

src/scribe/routes/lessons.py

@@ -28,6 +28,7 @@ from scribe.auth import get_current_user_id, login_required
 from scribe.routes.utils import not_found, parse_pagination
 from scribe.services import dedup as dedup_svc
 from scribe.services import knowledge as knowledge_svc
+from scribe.services import lesson_rules as lesson_rules_svc
 from scribe.services import lessons as lessons_svc
 from scribe.services import systems as systems_svc
 from scribe.services import trash as trash_svc
@@ -136,6 +137,12 @@ async def create_lesson_route():
 
     project_id = data.get("project_id") or None
     learned_from = data.get("learned_from") or []
+    # The rules this lesson is an instance of (milestone 440). Validated before
+    # anything is written, as the MCP door does, so a bad id saves nothing.
+    try:
+        linked = await lesson_rules_svc.require_rules(uid, data.get("rule_ids") or [])
+    except ValueError as exc:
+        return jsonify({"error": str(exc)}), 400
 
     # The same near-duplicate gate the MCP create path applies. Two lessons
     # under one trigger compete in a single ranked list for one reserved slot,
@@ -165,10 +172,13 @@ async def create_lesson_route():
     )
     if data.get("system_ids") is not None:
         await systems_svc.set_record_systems(uid, note.id, data["system_ids"])
+    if linked:
+        await lesson_rules_svc.set_lesson_rules(uid, note.id, linked)
     out = lessons_svc.lesson_to_dict(note)
     out["systems"] = [
         s.to_dict() for s in await systems_svc.list_record_systems(uid, note.id)
     ]
+    await lesson_rules_svc.attach_lesson_rules(uid, [out])
     return jsonify(out), 201
 
 
@@ -194,6 +204,7 @@ async def get_lesson_route(lesson_id: int):
     )
     out.update(await describe_provenance(uid, note))
     await attach_usage([out])
+    await lesson_rules_svc.attach_lesson_rules(uid, [out])
     # Opening the detail view IS a pull — the operator chose to look. Tagged
     # apart from the MCP sources so "an agent was handed it" and "a human read
     # it" stay distinguishable; they mean different things for pruning (#2085).
@@ -233,9 +244,20 @@ async def update_lesson_route(lesson_id: int):
             ),
         }), 400
 
+    linked = None
+    if data.get("rule_ids") is not None:
+        try:
+            linked = await lesson_rules_svc.require_rules(uid, data["rule_ids"])
+        except ValueError as exc:
+            return jsonify({"error": str(exc)}), 400
+
     updated = await lessons_svc.update_lesson(owner_uid, lesson_id, **kwargs)
     if updated is None:
         return not_found("Lesson")
+    if linked is not None:
+        # The CALLER, for the reason system_ids below uses it: the rules named
+        # must be ones the person making the edit can read.
+        await lesson_rules_svc.set_lesson_rules(uid, lesson_id, linked)
     if data.get("system_ids") is not None:
         # The CALLER, not owner_uid (#4249). `set_record_systems` runs its own
         # `can_write_note` and links only Systems the acting user can read;
@@ -249,9 +271,28 @@ async def update_lesson_route(lesson_id: int):
         s.to_dict()
         for s in await systems_svc.list_record_systems(owner_uid, lesson_id)
     ]
+    await lesson_rules_svc.attach_lesson_rules(uid, [out])
     return jsonify(out)
 
 
+@lessons_bp.route("/<int:lesson_id>/rules/<int:rule_id>", methods=["PUT"])
+@login_required
+async def judge_lesson_link_route(lesson_id: int, rule_id: int):
+    """Confirm or reject one lesson→rule link — the REST twin of the MCP
+    `judge_lesson_link`. Body: {"verdict": "confirm" | "reject", "note": "…"}."""
+    uid = get_current_user_id()
+    data = await request.get_json() or {}
+    try:
+        link = await lesson_rules_svc.judge_link(
+            uid, lesson_id, rule_id, data.get("verdict", ""), data.get("note", ""),
+        )
+    except PermissionError:
+        return jsonify({"error": "Permission denied"}), 403
+    except ValueError as exc:
+        return jsonify({"error": str(exc)}), 400
+    return jsonify(link)
+
+
 @lessons_bp.route("/<int:lesson_id>", methods=["DELETE"])
 @login_required
 async def delete_lesson_route(lesson_id: int):

src/scribe/services/backup.py

@@ -16,6 +16,7 @@ from scribe.models.rule_usage import RuleUsageEvent
 from scribe.models.retrieval_tuning import RetrievalTuningEvent
 from scribe.models.canonical_system import CanonicalSystem
 from scribe.models.rulebook import RuleRelation, rule_systems as rule_systems_t
+from scribe.models.lesson_rule_link import LessonRuleLink
 from scribe.models.code_shape import CodeShape, CodeShapeEvent, CodeShapeUse
 from scribe.models.project import Project
 from scribe.models.repo_binding import RepoBinding
@@ -80,8 +81,12 @@ logger = logging.getLogger(__name__)
 # say whether it still measures anything. Both travel NULLABLE and unfilled —
 # a row written before the stamp existed restores unstamped, because inventing
 # the model it was measured under would turn "unknown" into a stated fact.
+# v18 (2026-10) added lesson_rule_links (milestone 440): which rule each lesson
+# is an instance of, and the judgments that confirmed or rejected each pair. A
+# confirmed link is a judgment nothing else records, and a rejected one is
+# what stops the pair being proposed again — losing either undoes work.
 # Bump when the serialized schema changes.
-BACKUP_VERSION = 17
+BACKUP_VERSION = 18
 
 # Every table this backup carries, by its REAL name. Paired with _NOT_INCLUDED
 # below, these two lists must together account for the entire schema — which is
@@ -119,6 +124,8 @@ _BACKED_UP = [
     # on the operator's behalf, a restore that kept the numbers and dropped the
     # reasons would leave an install tuned by nobody it can name.
     "retrieval_tuning_events",
+    # v18 (2026-10): lesson → rule links and their judgments (milestone 440).
+    "lesson_rule_links",
 ]
 
 # Tables intentionally NOT in the backup, surfaced in the payload so the gap is
@@ -212,6 +219,8 @@ _COLUMN_EXCLUSIONS: dict[str, set[str]] = {
     "record_systems": {"id", "created_at"},
     "note_supersessions": {"id", "created_at"},
     "rule_relations": {"id", "created_at"},
+    # The pair is the row; everything else is the judgment and its evidence.
+    "lesson_rule_links": {"id"},
     "note_usage_events": {"id"},
     # Same as the note twin: the surrogate key is re-issued on insert.
     "rule_usage_events": {"id"},
@@ -299,6 +308,7 @@ _IMPORT_COLUMN_EXCLUSIONS: dict[str, set[str]] = {
     "record_systems": {"id", "created_at"},
     "note_supersessions": {"id", "created_at"},
     "rule_relations": {"id", "created_at"},
+    "lesson_rule_links": {"id"},
     "note_usage_events": {"id"},
     "rule_usage_events": {"id"},
     "retrieval_tuning_events": {"id"},
@@ -692,6 +702,21 @@ def _rule_relation_rows(rows) -> list[dict]:
     ]
 
 
+def _lesson_rule_link_rows(rows) -> list[dict]:
+    """Which rule each lesson is an instance of, with the judgment's state,
+    reason and evidence (milestone 440). Ids are SOURCE ids, remapped through
+    the note and rule maps at restore."""
+    return [
+        {
+            "lesson_id": r.lesson_id, "rule_id": r.rule_id, "state": r.state,
+            "note": r.note, "evidence": r.evidence,
+            "judged_at": r.judged_at.isoformat() if r.judged_at else None,
+            "created_at": r.created_at.isoformat() if r.created_at else None,
+        }
+        for r in rows
+    ]
+
+
 def _rule_rows(rows) -> list[dict]:
     return [
         {
@@ -739,6 +764,7 @@ async def export_full_backup() -> dict:
             .join(CanonicalSystem, CanonicalSystem.id == rule_systems_t.c.canonical_id)
         )).all()
         rule_relations = (await session.execute(select(RuleRelation))).scalars().all()
+        lesson_rule_links = (await session.execute(select(LessonRuleLink))).scalars().all()
         record_systems = (await session.execute(select(RecordSystem))).scalars().all()
         supersessions = (
             await session.execute(select(NoteSupersession))
@@ -797,6 +823,7 @@ async def export_full_backup() -> dict:
         "canonical_systems": _canonical_system_rows(canonical_systems),
         "rule_systems": _rule_system_rows(rule_system_rows),
         "rule_relations": _rule_relation_rows(rule_relations),
+        "lesson_rule_links": _lesson_rule_link_rows(lesson_rule_links),
         "systems": _system_rows(
             systems, {c.id: c.slug for c in canonical_systems}
         ),
@@ -957,6 +984,14 @@ async def export_user_backup(user_id: int) -> dict:
                 RuleRelation.to_rule_id.in_(_rule_ids),
             )
         )).scalars().all() if _rule_ids else []
+        # Both ends in THIS user's export, for the supersession reason: a link
+        # to a lesson or rule the import will not create restores as nothing.
+        lesson_rule_links = (await session.execute(
+            select(LessonRuleLink).where(
+                LessonRuleLink.lesson_id.in_(note_ids),
+                LessonRuleLink.rule_id.in_(_rule_ids),
+            )
+        )).scalars().all() if (_rule_ids and note_ids) else []
 
     return {
         "version": BACKUP_VERSION,
@@ -984,6 +1019,7 @@ async def export_user_backup(user_id: int) -> dict:
         "canonical_systems": _canonical_system_rows(canonical_systems),
         "rule_systems": _rule_system_rows(rule_system_rows),
         "rule_relations": _rule_relation_rows(rule_relations),
+        "lesson_rule_links": _lesson_rule_link_rows(lesson_rule_links),
         "systems": _system_rows(
             systems, {c.id: c.slug for c in canonical_systems}
         ),
@@ -1329,6 +1365,26 @@ def _build_rule_relation(row: dict, maps: _Maps) -> RuleRelation | None:
     )
 
 
+def _build_lesson_rule_link(row: dict, maps: _Maps) -> LessonRuleLink | None:
+    """Both ends must map: a link whose lesson or rule did not restore points
+    at whatever took that number in the destination."""
+    lesson = maps.notes.get(row.get("lesson_id", 0))
+    rule = maps.rules.get(row.get("rule_id", 0))
+    if lesson is None or rule is None:
+        return None
+    return LessonRuleLink(
+        lesson_id=lesson,
+        rule_id=rule,
+        state=row.get("state") or "suggested",
+        note=row.get("note") or None,
+        evidence=row.get("evidence"),
+        # Kept absent when absent: a suggested link was never judged, and
+        # stamping it with the restore time would say it was.
+        judged_at=_dt_or_none(row.get("judged_at")),
+        created_at=_dt(row.get("created_at")),
+    )
+
+
 def _build_rule_version(row: dict, maps: _Maps) -> RuleVersion | None:
     rid = maps.rules.get(row.get("rule_id", 0))
     if rid is None:
@@ -1725,7 +1781,7 @@ async def _restore_v2(data: dict) -> dict:
         "note_supersessions": 0, "code_shapes": 0, "code_shape_events": 0,
         "code_shape_uses": 0, "canonical_systems": 0,
         "rule_systems": 0, "rule_relations": 0, "rule_versions": 0,
-        "retrieval_tuning_events": 0,
+        "retrieval_tuning_events": 0, "lesson_rule_links": 0,
     }
 
     async with async_session() as session:
@@ -1920,6 +1976,16 @@ async def _restore_v2(data: dict) -> dict:
             session.add(relation)
             stats["rule_relations"] += 1
 
+        # Lesson → rule links (milestone 440): after both notes and rules are
+        # mapped, which is why they sit beside the rule edges. Archives before
+        # v18 carry no section and restore with none.
+        for lr in data.get("lesson_rule_links", []):
+            link = _build_lesson_rule_link(lr, maps)
+            if link is None:
+                continue
+            session.add(link)
+            stats["lesson_rule_links"] += 1
+
         # A rule's edit history (milestone 323). Must come after the rules
         # themselves — the rule map is only populated above — and both ids are
         # ids in the SOURCE database, which is #3182's arose_from_id trap.

src/scribe/services/lesson_rules.py

@@ -0,0 +1,244 @@
+"""Lessons point at rules (milestone 440, #4196).
+
+A lesson is a non-binding record of one situation; a rule is the binding
+choice for a class of them. This service owns the link between the two — which
+rule a lesson is an instance of — and both directions of reading it.
+
+THE STATES (models/lesson_rule_link.py says why each exists):
+`suggested` while evidence accumulates, `confirmed` or `rejected` once a
+judgment is made. Every write here is a JUDGMENT, so every write lands as
+confirmed or rejected; `suggested` rows come from the co-surfacing recorder
+(#4637), never from a caller naming a rule.
+
+ACL (rule 78). Linking changes what a lesson says about itself, so it needs
+WRITE on the lesson (`access.can_write_note`, share-aware). It names a rule, so
+it needs the rule to be one the caller may read — rules are owner-scoped, and
+`rulebooks._fetch_owned_rule` / `_owned_rules_clause` are that check's two
+forms. A read shows only the rules the READER owns: a lesson shared with
+someone must not hand them the titles of its owner's private rules.
+"""
+from __future__ import annotations
+
+import logging
+from datetime import datetime, timezone
+
+from sqlalchemy import select
+
+from scribe.models import async_session
+from scribe.models.lesson_rule_link import CONFIRMED, REJECTED, SUGGESTED, LessonRuleLink
+from scribe.models.note import Note
+from scribe.models.rulebook import Rule
+
+logger = logging.getLogger(__name__)
+
+# What a caller says to judge one pair. Words rather than the stored states,
+# because "confirm" and "reject" are acts and the states are their results.
+VERDICTS = {"confirm": CONFIRMED, "reject": REJECTED}
+
+# Recorded on a link that set-semantics removed, so a reader of the rejected
+# row can tell an explicit "not this rule" from a link dropped by a rewrite.
+_REMOVED_NOTE = "removed from the lesson's rules by an update"
+
+
+def _ids(values) -> list[int]:
+    """Positive ints, de-duplicated, in the order given."""
+    out: list[int] = []
+    for v in values or []:
+        try:
+            i = int(v)
+        except (TypeError, ValueError):
+            raise ValueError(f"rule id {v!r} is not an integer")
+        if i > 0 and i not in out:
+            out.append(i)
+    return out
+
+
+async def _require_lesson_writable(user_id: int, lesson_id: int) -> None:
+    from scribe.services import access
+    from scribe.services import lessons as lessons_svc
+
+    note = await lessons_svc.get_lesson(user_id, lesson_id)
+    if note is None:
+        raise ValueError(f"lesson {lesson_id} not found")
+    if not await access.can_write_note(user_id, lesson_id):
+        raise PermissionError(f"lesson {lesson_id} is not yours to change")
+
+
+async def require_rules(user_id: int, rule_ids) -> list[int]:
+    """The ids, validated as rules the caller owns — all of them or none.
+
+    Checked BEFORE anything is written, by every caller, so a lesson create
+    that names a rule it cannot see fails without leaving a half-linked
+    lesson behind.
+    """
+    from scribe.services import rulebooks as rulebooks_svc
+
+    wanted = _ids(rule_ids)
+    missing = [rid for rid in wanted if await rulebooks_svc.get_rule(rid, user_id) is None]
+    if missing:
+        raise ValueError(
+            f"rule(s) {missing} not found — a lesson can point only at a rule "
+            "you can read. Nothing was linked."
+        )
+    return wanted
+
+
+async def _upsert(session, lesson_id: int, rule_id: int, state: str, note: str) -> None:
+    now = datetime.now(timezone.utc)
+    row = (await session.execute(
+        select(LessonRuleLink).where(
+            LessonRuleLink.lesson_id == lesson_id,
+            LessonRuleLink.rule_id == rule_id,
+        )
+    )).scalar_one_or_none()
+    if row is None:
+        session.add(LessonRuleLink(
+            lesson_id=lesson_id, rule_id=rule_id, state=state,
+            note=note or None, judged_at=now,
+        ))
+        return
+    # Evidence is kept across a judgment: a confirmation reads best beside
+    # what it rested on.
+    row.state = state
+    row.note = note or row.note
+    row.judged_at = now
+
+
+async def set_lesson_rules(
+    user_id: int, lesson_id: int, rule_ids, *, note: str = "",
+) -> None:
+    """Make the lesson's CONFIRMED rules exactly `rule_ids` (set-semantics).
+
+    A rule named here is confirmed, whatever state it was in: the writer of a
+    lesson saying "this is an instance of rule N" is the judgment the
+    suggested state waits for, so it needs no evidence bar.
+
+    A rule that WAS confirmed and is no longer named becomes `rejected`, not
+    deleted. Dropping it is a judgment that the lesson is not an instance of
+    that rule, and a deleted row would let the co-surfacing recorder propose
+    the same pair again.
+    """
+    await _require_lesson_writable(user_id, lesson_id)
+    wanted = await require_rules(user_id, rule_ids)
+    async with async_session() as session:
+        current = (await session.execute(
+            select(LessonRuleLink).where(
+                LessonRuleLink.lesson_id == lesson_id,
+                LessonRuleLink.state == CONFIRMED,
+            )
+        )).scalars().all()
+        for row in current:
+            if row.rule_id not in wanted:
+                row.state = REJECTED
+                row.note = _REMOVED_NOTE
+                row.judged_at = datetime.now(timezone.utc)
+        for rid in wanted:
+            await _upsert(session, lesson_id, rid, CONFIRMED, note)
+        await session.commit()
+
+
+async def judge_link(
+    user_id: int, lesson_id: int, rule_id: int, verdict: str, note: str = "",
+) -> dict:
+    """Confirm or reject one (lesson, rule) pair, suggested or not."""
+    state = VERDICTS.get((verdict or "").strip().lower())
+    if state is None:
+        raise ValueError(f"verdict must be one of {sorted(VERDICTS)}, got {verdict!r}")
+    await _require_lesson_writable(user_id, lesson_id)
+    [rid] = await require_rules(user_id, [rule_id])
+    async with async_session() as session:
+        await _upsert(session, lesson_id, rid, state, note)
+        await session.commit()
+        row = (await session.execute(
+            select(LessonRuleLink).where(
+                LessonRuleLink.lesson_id == lesson_id,
+                LessonRuleLink.rule_id == rid,
+            )
+        )).scalar_one()
+        return row.to_dict()
+
+
+async def rules_for_lessons(user_id: int, lesson_ids) -> dict[int, list[dict]]:
+    """{lesson_id: [{id, title, kind, state, note}]}, for rules the READER owns.
+
+    One query for the whole set — a lesson list would otherwise be N+1.
+    Confirmed first, then suggested, then rejected: the order a reader cares
+    about them in.
+    """
+    from scribe.services.rulebooks import _owned_rules_clause
+
+    ids = [int(i) for i in lesson_ids or []]
+    out: dict[int, list[dict]] = {i: [] for i in ids}
+    if not ids:
+        return out
+    order = {s: n for n, s in enumerate((CONFIRMED, SUGGESTED, REJECTED))}
+    async with async_session() as session:
+        rows = (await session.execute(
+            select(LessonRuleLink, Rule)
+            .join(Rule, Rule.id == LessonRuleLink.rule_id)
+            .where(LessonRuleLink.lesson_id.in_(ids))
+            .where(_owned_rules_clause(user_id))
+        )).all()
+    for link, rule in sorted(rows, key=lambda r: (order.get(r[0].state, 9), r[1].id)):
+        out[link.lesson_id].append({
+            "id": rule.id, "title": rule.title, "kind": rule.kind,
+            "state": link.state, "note": link.note or "",
+        })
+    return out
+
+
+async def lessons_for_rule(user_id: int, rule_id: int) -> list[dict]:
+    """The lessons that point at one rule, readable by the caller (share-aware).
+
+    The reverse direction, and the one a rule's page needs: the concrete
+    situations that have been judged instances of it.
+    """
+    from scribe.services.access import readable_notes_clause
+
+    async with async_session() as session:
+        rows = (await session.execute(
+            select(LessonRuleLink, Note)
+            .join(Note, Note.id == LessonRuleLink.lesson_id)
+            .where(LessonRuleLink.rule_id == int(rule_id))
+            .where(Note.deleted_at.is_(None))
+            .where(readable_notes_clause(user_id))
+        )).all()
+    order = {s: n for n, s in enumerate((CONFIRMED, SUGGESTED, REJECTED))}
+    return [
+        {"id": note.id, "title": note.title, "state": link.state, "note": link.note or ""}
+        for link, note in sorted(rows, key=lambda r: (order.get(r[0].state, 9), r[1].id))
+    ]
+
+
+async def attach_lesson_rules(user_id: int, rows: list[dict], *, key: str = "id") -> None:
+    """Add `rules` to each lesson payload row, in place — one query per page.
+
+    Fail-open (snippet #4286): this decorates a lesson the caller already has,
+    so a failed lookup leaves the key off and logs, rather than refusing the
+    lesson. An absent key reads as "not attached", never as "no rule".
+    """
+    ids = [int(r[key]) for r in rows if isinstance(r.get(key), int)]
+    try:
+        found = await rules_for_lessons(user_id, ids)
+    except Exception:
+        logger.warning("lesson→rule links could not be read", exc_info=True)
+        return
+    for r in rows:
+        if isinstance(r.get(key), int):
+            r["rules"] = found.get(r[key], [])
+
+
+async def attach_rule_lessons(user_id: int, data: dict, rule_id: int) -> None:
+    """Add `lessons` to a rule payload, in place, when there are any.
+
+    Present-only, as a rule's `systems` and `relations` are (#2483), and
+    fail-open for the reason `attach_lesson_rules` gives.
+    """
+    try:
+        lessons = await lessons_for_rule(user_id, rule_id)
+    except Exception:
+        logger.warning("rule→lesson links could not be read", exc_info=True)
+        return
+    if lessons:
+        data["lessons"] = lessons
+

src/scribe/services/rulebooks.py

@@ -455,6 +455,11 @@ async def rule_detail(user_id: int, rule: Rule, system_ids: list[int] | None = N
         data["systems"] = systems
     if relations:
         data["relations"] = relations
+    # The concrete situations judged (or proposed) to be instances of this
+    # rule — milestone 440. Same present-only convention as the two above.
+    from scribe.services.lesson_rules import attach_rule_lessons
+
+    await attach_rule_lessons(user_id, data, rule.id)
     return data
 
 

tests/conftest.py

@@ -142,6 +142,27 @@ def _no_task_log_arm():
         yield
 
 
+@pytest.fixture(autouse=True)
+def _no_lesson_rule_links(request):
+    """Stub the lesson↔rule link decorations (milestone 440).
+
+    Every door that returns a lesson or a rule now attaches its links, and the
+    read is a real database call — so every unit test that opens either would
+    otherwise reach for the fake DATABASE_URL to learn that nothing is linked.
+    Both decorations are fail-open, so the cost would be a slow failed connect
+    per test rather than a failure, which is worse: it would never be noticed.
+
+    Skipped for integration tests, which exercise the real links against
+    Postgres (tests/test_integration_lesson_rule_links.py).
+    """
+    if request.node.get_closest_marker("integration"):
+        yield
+        return
+    with patch("scribe.services.lesson_rules.attach_lesson_rules", AsyncMock()), \
+         patch("scribe.services.lesson_rules.attach_rule_lessons", AsyncMock()):
+        yield
+
+
 @pytest.fixture(autouse=True)
 def _no_rule_arm():
     """Stub the write-path hint's standing-RULES arm (milestone 307).

tests/test_integration_lesson_rule_links.py

@@ -0,0 +1,162 @@
+"""Real-Postgres tests for lesson → rule links (milestone 440 step 1, #4630).
+
+What a mock cannot show: that the CHECK holds the three states, that deleting
+either end takes the link with it, that a rule the caller does not own cannot
+be linked (and nothing is half-written when one id is bad), and that each side
+reads only what its reader may see.
+"""
+import uuid
+from unittest.mock import MagicMock, patch
+
+import pytest
+import pytest_asyncio
+from sqlalchemy import delete, select
+from sqlalchemy.exc import IntegrityError
+
+from scribe.models import async_session
+from scribe.models.lesson_rule_link import LessonRuleLink
+from scribe.models.note import Note
+from scribe.models.project import Project
+from scribe.models.rulebook import Rule
+from scribe.services import lesson_rules as links_svc
+from scribe.services import lessons as lessons_svc
+from scribe.services import rulebooks as rulebooks_svc
+from tests.helpers import ensure_user
+
+pytestmark = [
+    pytest.mark.integration,
+    pytest.mark.usefixtures("_dispose_engine", "_no_embedding"),
+]
+
+
+@pytest.fixture(autouse=True)
+def _no_reindex():
+    """Rule writes detach an embedding refresh that outlives the test's loop."""
+    with patch("scribe.services.rulebooks._refresh_rule_embedding", MagicMock()):
+        yield
+
+
+@pytest_asyncio.fixture
+async def world():
+    """An owner with a lesson and two rules; a stranger with a rule of their own."""
+    tag = uuid.uuid4().hex[:8]
+    async with async_session() as s:
+        owner = await ensure_user(s, f"lrl_owner_{tag}")
+        stranger = await ensure_user(s, f"lrl_stranger_{tag}")
+        mine = Project(user_id=owner.id, title="Mine")
+        theirs = Project(user_id=stranger.id, title="Theirs")
+        s.add_all([mine, theirs])
+        await s.flush()
+        ids = {"owner": owner.id, "stranger": stranger.id,
+               "mine": mine.id, "theirs": theirs.id}
+        await s.commit()
+
+    owner = ids["owner"]
+    r1 = await rulebooks_svc.create_project_rule(
+        ids["mine"], owner, "Read the job log first", "Before waiting longer.",
+        when_to_apply="a CI run has overrun its usual duration",
+    )
+    r2 = await rulebooks_svc.create_project_rule(
+        ids["mine"], owner, "Probe the system itself", "Not a proxy for it.",
+        when_to_apply="about to state what version is deployed",
+    )
+    foreign = await rulebooks_svc.create_project_rule(
+        ids["theirs"], ids["stranger"], "Their rule", "Not yours.",
+        when_to_apply="something only they do",
+    )
+    lesson = await lessons_svc.create_lesson(
+        owner, what="An overrun run usually failed early",
+        when_to_apply="a CI run is still in_progress far past its usual time",
+        insight="Read the log; the failure is often minutes old.",
+        project_id=ids["mine"],
+    )
+    ids.update(r1=r1.id, r2=r2.id, foreign=foreign.id, lesson=lesson.id)
+    return ids
+
+
+async def _states(lesson_id: int) -> dict[int, str]:
+    async with async_session() as s:
+        rows = (await s.execute(
+            select(LessonRuleLink).where(LessonRuleLink.lesson_id == lesson_id)
+        )).scalars().all()
+    return {r.rule_id: r.state for r in rows}
+
+
+async def test_naming_rules_confirms_them_and_both_sides_read_the_link(world):
+    owner = world["owner"]
+    await links_svc.set_lesson_rules(owner, world["lesson"], [world["r1"], world["r2"]])
+
+    assert await _states(world["lesson"]) == {world["r1"]: "confirmed", world["r2"]: "confirmed"}
+    rules = (await links_svc.rules_for_lessons(owner, [world["lesson"]]))[world["lesson"]]
+    assert {r["id"] for r in rules} == {world["r1"], world["r2"]}
+    lessons = await links_svc.lessons_for_rule(owner, world["r1"])
+    assert [(l["id"], l["state"]) for l in lessons] == [(world["lesson"], "confirmed")]
+
+
+async def test_a_rule_left_out_of_the_set_is_rejected_not_forgotten(world):
+    owner = world["owner"]
+    await links_svc.set_lesson_rules(owner, world["lesson"], [world["r1"], world["r2"]])
+    await links_svc.set_lesson_rules(owner, world["lesson"], [world["r1"]])
+
+    assert await _states(world["lesson"]) == {world["r1"]: "confirmed", world["r2"]: "rejected"}
+    rules = (await links_svc.rules_for_lessons(owner, [world["lesson"]]))[world["lesson"]]
+    # Confirmed reads first; the rejection keeps its reason.
+    assert [r["state"] for r in rules] == ["confirmed", "rejected"]
+    assert rules[1]["note"] == links_svc._REMOVED_NOTE
+
+
+async def test_judge_moves_a_pair_both_ways_and_refuses_a_nonsense_verdict(world):
+    owner = world["owner"]
+    out = await links_svc.judge_link(owner, world["lesson"], world["r1"], "reject", "different failure")
+    assert (out["state"], out["note"]) == ("rejected", "different failure")
+    assert out["judged_at"] is not None
+    out = await links_svc.judge_link(owner, world["lesson"], world["r1"], "confirm")
+    assert out["state"] == "confirmed"
+    with pytest.raises(ValueError):
+        await links_svc.judge_link(owner, world["lesson"], world["r1"], "maybe")
+
+
+async def test_a_rule_the_caller_cannot_read_links_nothing_at_all(world):
+    """All-or-nothing: one unreadable id refuses the whole set, so the readable
+    one beside it is not linked either."""
+    with pytest.raises(ValueError):
+        await links_svc.set_lesson_rules(
+            world["owner"], world["lesson"], [world["r1"], world["foreign"]],
+        )
+    assert await _states(world["lesson"]) == {}
+
+
+async def test_a_stranger_cannot_link_someone_elses_lesson(world):
+    with pytest.raises((ValueError, PermissionError)):
+        await links_svc.set_lesson_rules(world["stranger"], world["lesson"], [world["foreign"]])
+    assert await _states(world["lesson"]) == {}
+
+
+async def test_deleting_either_end_takes_the_link_with_it(world):
+    owner = world["owner"]
+    await links_svc.set_lesson_rules(owner, world["lesson"], [world["r1"], world["r2"]])
+    async with async_session() as s:
+        await s.execute(delete(Rule).where(Rule.id == world["r1"]))
+        await s.commit()
+    assert await _states(world["lesson"]) == {world["r2"]: "confirmed"}
+    async with async_session() as s:
+        await s.execute(delete(Note).where(Note.id == world["lesson"]))
+        await s.commit()
+    assert await _states(world["lesson"]) == {}
+
+
+async def test_the_check_holds_the_three_states(world):
+    async with async_session() as s:
+        s.add(LessonRuleLink(lesson_id=world["lesson"], rule_id=world["r1"], state="maybe"))
+        with pytest.raises(IntegrityError):
+            await s.commit()
+
+
+async def test_one_row_per_pair(world):
+    async with async_session() as s:
+        s.add_all([
+            LessonRuleLink(lesson_id=world["lesson"], rule_id=world["r1"], state="suggested"),
+            LessonRuleLink(lesson_id=world["lesson"], rule_id=world["r1"], state="confirmed"),
+        ])
+        with pytest.raises(IntegrityError):
+            await s.commit()

tests/test_lesson_rule_link_doors.py

@@ -0,0 +1,145 @@
+"""The lesson → rule link at its doors (milestone 440 step 1, #4630).
+
+The link's own behaviour — states, cascade, ACL — is tested against Postgres in
+tests/test_integration_lesson_rule_links.py. These pin the wiring a mock CAN
+see: that a bad rule id stops a lesson create before anything is written, that
+the doors pass the set through with the semantics their docstrings promise,
+that the judge tool is registered, that backup skips a link it cannot map, and
+that the migration and the model agree about the states.
+"""
+from __future__ import annotations
+
+import importlib.util
+from pathlib import Path
+from types import SimpleNamespace
+from unittest.mock import AsyncMock, patch
+
+import pytest
+
+from scribe.mcp._context import _user_id_ctx
+from scribe.mcp.tools import lessons as lesson_tools
+from scribe.models.lesson_rule_link import LINK_STATES
+from scribe.services import backup
+from scribe.services import lesson_rules as links_svc
+from scribe.services import lessons as lessons_svc
+
+TRIGGER = "a CI run is still in_progress far past its usual time"
+
+
+def _stub_note(**kw):
+    base = dict(
+        id=41, title="t", body="b", tags=[], project_id=None,
+        note_type="lesson", data={}, arose_from_id=None,
+        created_at=None, updated_at=None,
+    )
+    base.update(kw)
+    return SimpleNamespace(**base)
+
+
+def _create_patches(created):
+    return (
+        patch.object(lessons_svc, "create_lesson", created),
+        patch("scribe.mcp.tools.lessons.dedup_svc.find_duplicate_note",
+              AsyncMock(return_value=None)),
+        patch("scribe.mcp.tools.lessons.systems_tools.attach_systems", AsyncMock()),
+    )
+
+
+@pytest.mark.asyncio
+async def test_an_unreadable_rule_stops_the_lesson_before_it_is_written():
+    """All-or-nothing at the door: the rule ids are validated BEFORE the
+    lesson exists, so a bad id cannot leave a lesson saved and unlinked."""
+    _user_id_ctx.set(7)
+    created = AsyncMock(return_value=_stub_note())
+    p1, p2, p3 = _create_patches(created)
+    with p1, p2, p3, patch.object(
+        links_svc, "require_rules", AsyncMock(side_effect=ValueError("rule(s) [9] not found")),
+    ):
+        with pytest.raises(ValueError):
+            await lesson_tools.create_lesson(what="x", when_to_apply=TRIGGER, rule_ids=[9])
+    created.assert_not_awaited()
+
+
+@pytest.mark.asyncio
+async def test_create_links_the_named_rules_to_the_new_lesson():
+    _user_id_ctx.set(7)
+    created = AsyncMock(return_value=_stub_note(id=41))
+    linked = AsyncMock()
+    p1, p2, p3 = _create_patches(created)
+    with p1, p2, p3, \
+         patch.object(links_svc, "require_rules", AsyncMock(return_value=[5, 6])), \
+         patch.object(links_svc, "set_lesson_rules", linked):
+        await lesson_tools.create_lesson(what="x", when_to_apply=TRIGGER, rule_ids=[5, 6])
+    linked.assert_awaited_once()
+    assert linked.await_args.args[1:] == (41, [5, 6])
+
+
+@pytest.mark.asyncio
+async def test_create_without_rules_writes_no_link():
+    _user_id_ctx.set(7)
+    linked = AsyncMock()
+    p1, p2, p3 = _create_patches(AsyncMock(return_value=_stub_note()))
+    with p1, p2, p3, patch.object(links_svc, "set_lesson_rules", linked):
+        await lesson_tools.create_lesson(what="x", when_to_apply=TRIGGER)
+    linked.assert_not_awaited()
+
+
+@pytest.mark.parametrize("rule_ids, expect_call", [(None, False), ([], True), ([5], True)])
+@pytest.mark.asyncio
+async def test_update_leaves_links_alone_on_none_and_replaces_on_a_list(rule_ids, expect_call):
+    """None is "unchanged"; a list — including [] — is the full new set, which
+    the service turns into confirmations and rejections."""
+    _user_id_ctx.set(7)
+    linked = AsyncMock()
+    with patch.object(lessons_svc, "update_lesson", AsyncMock(return_value=_stub_note())), \
+         patch.object(links_svc, "require_rules", AsyncMock(side_effect=lambda uid, ids: list(ids))), \
+         patch.object(links_svc, "set_lesson_rules", linked):
+        await lesson_tools.update_lesson(lesson_id=41, rule_ids=rule_ids)
+    assert linked.await_count == (1 if expect_call else 0)
+    if expect_call:
+        assert linked.await_args.args[1:] == (41, rule_ids)
+
+
+def test_the_judge_tool_is_registered():
+    names = []
+    fake = SimpleNamespace(tool=lambda name: (lambda fn: names.append(name) or fn))
+    lesson_tools.register(fake)
+    assert "judge_lesson_link" in names
+
+
+def test_verdicts_name_real_states():
+    assert set(links_svc.VERDICTS.values()) <= set(LINK_STATES)
+
+
+def test_the_migration_check_and_the_model_agree_on_the_states():
+    """Rule 36's drift, guarded: the CHECK is written from the migration's
+    tuple and the code from the model's, so they must be the same tuple."""
+    path = Path(__file__).resolve().parents[1] / "alembic" / "versions" / "0111_lesson_rule_links.py"
+    spec = importlib.util.spec_from_file_location("m0111", path)
+    module = importlib.util.module_from_spec(spec)
+    spec.loader.exec_module(module)
+    assert tuple(module._STATES) == tuple(LINK_STATES)
+
+
+@pytest.mark.parametrize("lesson_mapped, rule_mapped", [(False, True), (True, False)])
+def test_backup_skips_a_link_whose_end_did_not_restore(lesson_mapped, rule_mapped):
+    maps = backup._Maps()
+    if lesson_mapped:
+        maps.notes[10] = 110
+    if rule_mapped:
+        maps.rules[20] = 120
+    row = {"lesson_id": 10, "rule_id": 20, "state": "confirmed"}
+    assert backup._build_lesson_rule_link(row, maps) is None
+
+
+def test_backup_keeps_an_unjudged_link_unjudged():
+    """A suggested link was never judged; restoring it with the restore's time
+    in judged_at would say it was."""
+    maps = backup._Maps()
+    maps.notes[10] = 110
+    maps.rules[20] = 120
+    built = backup._build_lesson_rule_link(
+        {"lesson_id": 10, "rule_id": 20, "state": "suggested", "judged_at": None}, maps,
+    )
+    assert (built.lesson_id, built.rule_id, built.state) == (110, 120, "suggested")
+    assert built.judged_at is None

tests/test_services_backup.py

@@ -27,7 +27,7 @@ def test_backup_version_is_current():
 
     (Named for the number it asserted until v10, which is exactly the drift a
     name-carrying-a-value invites; it now says what it checks.)"""
-    assert backup.BACKUP_VERSION == 17
+    assert backup.BACKUP_VERSION == 18
 
 
 def _exportable_note(**over):
@@ -131,6 +131,7 @@ def test_a_repo_binding_carries_the_branch_its_ledger_follows():
 def _column_guard_targets():
     from scribe.models.canonical_system import CanonicalSystem
     from scribe.models.code_shape import CodeShape, CodeShapeEvent, CodeShapeUse
+    from scribe.models.lesson_rule_link import LessonRuleLink
     from scribe.models.design_system import DesignSystem, DesignToken
     from scribe.models.milestone import Milestone
     from scribe.models.note import Note
@@ -167,6 +168,7 @@ def _column_guard_targets():
         "record_systems": (RecordSystem, backup._record_system_rows),
         "note_supersessions": (NoteSupersession, backup._note_supersession_rows),
         "rule_relations": (RuleRelation, backup._rule_relation_rows),
+        "lesson_rule_links": (LessonRuleLink, backup._lesson_rule_link_rows),
         "note_usage_events": (NoteUsageEvent, backup._usage_event_rows),
         "rule_usage_events": (RuleUsageEvent, backup._rule_usage_event_rows),
         "retrieval_tuning_events": (
@@ -283,6 +285,7 @@ def _import_guard_targets():
         "record_systems": backup._build_record_system,
         "note_supersessions": backup._build_note_supersession,
         "rule_relations": backup._build_rule_relation,
+        "lesson_rule_links": backup._build_lesson_rule_link,
         "note_usage_events": backup._build_usage_event,
         "rule_usage_events": backup._build_rule_usage_event,
         "retrieval_tuning_events": backup._build_retrieval_tuning_event,
@@ -534,7 +537,9 @@ async def test_export_full_backup_contains_every_declared_section():
                 "note_supersessions", "code_shapes", "code_shape_events",
                 "code_shape_uses",
                 # v16: the reasons beside the settings they explain.
-                "retrieval_tuning_events"):
+                "retrieval_tuning_events",
+                # v18: which rule each lesson is an instance of.
+                "lesson_rule_links"):
         assert key in out, f"missing export section: {key}"
         assert out[key] == []