diff --git a/alembic/versions/0087_canonical_systems.py b/alembic/versions/0087_canonical_systems.py
new file mode 100644
index 0000000..a765b80
--- /dev/null
+++ b/alembic/versions/0087_canonical_systems.py
@@ -0,0 +1,109 @@
+"""canonical_systems — the global area vocabulary, promoted from a constant
+to a table (milestone 307 step 1, decision note 3026)
+
+Revision ID: 0087
+Revises: 0086
+Create Date: 2026-08-26
+
+The eight standard area names already existed as `STANDARD_SYSTEMS`, a tuple in
+services/systems.py that milestone 297 seeds into a project at inception. A
+constant cannot be referenced: a rule that applies across projects has nothing
+to point at, because `systems.project_id` is NOT NULL and a family rule cannot
+be chained to one project's row. This makes the vocabulary a table so it can be
+a foreign key, and adds the nullable `systems.canonical_id` that maps a
+project's local System onto it.
+
+Deliberately no `user_id`: the catalog is GLOBAL so a shared project inherits
+the vocabulary rather than re-earning it. `record_systems` is untouched — it
+joins note_id/system_id and never sees this table, so no association data
+moves, and no System's own `name` is rewritten.
+
+The seed rows are written here verbatim rather than imported from the service:
+a migration is a historical record and must keep running unchanged after the
+service's list moves on.
+"""
+import sqlalchemy as sa
+from alembic import op
+
+revision = "0087"
+down_revision = "0086"
+branch_labels = None
+depends_on = None
+
+
+# (name, slug, description) — the milestone-297 vocabulary, with the slug the
+# service computes (canonical_slug: lowercase, "&" -> "and", non-alphanumerics
+# collapsed to "-"). Charters stay generic on purpose: a project refines its
+# own System's description, never this one. Nothing here names an app, a repo,
+# a vendor or a house convention — the catalog ships to every install (rule 115).
+_SEED = (
+    ("CI & Release", "ci-and-release",
+     "How the project is verified and shipped: pipelines, runners, image/artifact builds, release tagging and rollback."),
+    ("Auth & Access", "auth-and-access",
+     "Who may do what: identity, sessions/tokens, permissions and the scoping of every read and write to the right users."),
+    ("Data Model & Storage", "data-model-and-storage",
+     "What is stored and how it is shaped: the schema, migrations, serialisation and the services that own a table's lifecycle."),
+    ("API Surface", "api-surface",
+     "The doors into the capability: HTTP routes, tool/RPC surfaces, request parsing, error envelopes and their contracts."),
+    ("UI & Design", "ui-and-design",
+     "What people see and touch: views, components, client state, and the design tokens/recipes they are built from."),
+    ("Import & Export", "import-and-export",
+     "Data crossing the boundary: backups, exports, imports, sync with other systems, file formats."),
+    ("Background Jobs", "background-jobs",
+     "Work that runs without a request: schedulers, queues, periodic ticks, retention and maintenance."),
+    ("Observability", "observability",
+     "How the system reports on itself: logging, metrics, audit trails, health and diagnostics."),
+)
+
+
+def upgrade() -> None:
+    canonical_systems = op.create_table(
+        "canonical_systems",
+        sa.Column("id", sa.Integer(), primary_key=True),
+        sa.Column("name", sa.Text(), nullable=False),
+        sa.Column("slug", sa.Text(), nullable=False),
+        sa.Column("description", sa.Text(), nullable=True),
+        sa.Column("order_index", sa.Integer(), nullable=False, server_default="0"),
+        sa.Column("created_at", sa.DateTime(timezone=True), nullable=False, server_default=sa.text("now()")),
+        sa.Column("updated_at", sa.DateTime(timezone=True), nullable=False, server_default=sa.text("now()")),
+        sa.Column("deleted_at", sa.DateTime(timezone=True), nullable=True),
+        sa.Column("deleted_batch_id", sa.Text(), nullable=True),
+    )
+    # Unique among LIVE rows only, so a soft-deleted entry doesn't block
+    # recreating or restoring the same area (the rules/topics convention).
+    op.create_index(
+        "uq_canonical_systems_slug", "canonical_systems", ["slug"],
+        unique=True, postgresql_where=sa.text("deleted_at IS NULL"),
+    )
+    op.bulk_insert(
+        canonical_systems,
+        [
+            {"name": name, "slug": slug, "description": description, "order_index": index}
+            for index, (name, slug, description) in enumerate(_SEED)
+        ],
+    )
+
+    op.add_column(
+        "systems",
+        sa.Column("canonical_id", sa.Integer(), nullable=True),
+    )
+    # SET NULL, not CASCADE: retiring a catalog entry must never delete a
+    # project's System along with it.
+    op.create_foreign_key(
+        "fk_systems_canonical_id", "systems", "canonical_systems",
+        ["canonical_id"], ["id"], ondelete="SET NULL",
+    )
+    op.create_index("ix_systems_canonical_id", "systems", ["canonical_id"])
+
+    # Existing Systems are left UNMAPPED on purpose. An exact-slug match would
+    # be safe, but a near miss ("CI & runners" vs "CI & Release") is a judgment
+    # call — those go through the propose/confirm path so a human approves each
+    # one, rather than being decided by a migration nobody reviews.
+
+
+def downgrade() -> None:
+    op.drop_index("ix_systems_canonical_id", table_name="systems")
+    op.drop_constraint("fk_systems_canonical_id", "systems", type_="foreignkey")
+    op.drop_column("systems", "canonical_id")
+    op.drop_index("uq_canonical_systems_slug", table_name="canonical_systems")
+    op.drop_table("canonical_systems")
diff --git a/src/scribe/app.py b/src/scribe/app.py
index 55dcd86..da2e5ee 100644
--- a/src/scribe/app.py
+++ b/src/scribe/app.py
@@ -30,6 +30,7 @@ from scribe.routes.design_systems import design_systems_bp
 from scribe.routes.trash import trash_bp
 from scribe.routes.dashboard import dashboard_bp
 from scribe.routes.systems import systems_bp
+from scribe.routes.canonical_systems import canonical_systems_bp
 from scribe.routes.snippets import snippets_bp
 from scribe.routes.webhooks import webhooks_bp
 from scribe.mcp import mount_mcp
@@ -95,6 +96,7 @@ def create_app() -> Quart:
     app.register_blueprint(trash_bp)
     app.register_blueprint(dashboard_bp)
     app.register_blueprint(systems_bp)
+    app.register_blueprint(canonical_systems_bp)
     app.register_blueprint(snippets_bp)
     app.register_blueprint(webhooks_bp)
 
diff --git a/src/scribe/mcp/server.py b/src/scribe/mcp/server.py
index 5f0a8d5..93bc5e0 100644
--- a/src/scribe/mcp/server.py
+++ b/src/scribe/mcp/server.py
@@ -91,6 +91,9 @@ _READ_ONLY_TOOLS = frozenset({
     "list_rules", "list_tags", "list_tasks", "list_topics", "list_trash",
     "list_always_on_rules", "search",
     "get_system", "list_systems", "list_system_records",
+    # The global area catalog and its mapping REPORT — propose writes nothing;
+    # map_system_to_canonical is the separate, explicitly-called write.
+    "list_canonical_systems", "propose_canonical_mappings",
     # Reports on the corpus. Reads only — the merge or supersession each
     # suggests is a separate, explicitly-called write.
     "find_duplicate_snippets", "find_duplicate_records",
diff --git a/src/scribe/mcp/tools/systems.py b/src/scribe/mcp/tools/systems.py
index 2431d67..f03302a 100644
--- a/src/scribe/mcp/tools/systems.py
+++ b/src/scribe/mcp/tools/systems.py
@@ -13,6 +13,7 @@ Sentinels (match the milestone/task tool conventions):
 from __future__ import annotations
 
 from scribe.mcp._context import current_user_id
+from scribe.services import canonical_systems as canonical_systems_svc
 from scribe.services import notes as notes_svc
 from scribe.services import systems as systems_svc
 
@@ -30,10 +31,9 @@ _BOOTSTRAP_TITLES = 6
 # design (rule #115): archetypes any codebase could have, never one
 # install's subsystems. Mint freely beyond the list; the duplicate gate
 # guards sprawl.
-# The standard vocabulary lives with the service (services/systems.
-# STANDARD_SYSTEMS) since milestone 297 — the inception seed mints it and this
-# ask names it, one list for both.
-_STANDARD_SYSTEMS = tuple(name for name, _charter in systems_svc.STANDARD_SYSTEMS)
+# The standard vocabulary lives in the GLOBAL canonical catalog since
+# milestone 307 — the inception seed mints it and this ask names it, one list
+# for both, now a table so a rule can reference an area by id (note 3026).
 
 
 async def bootstrap_systems_ask(user_id: int, project_id: int) -> str | None:
@@ -67,6 +67,17 @@ async def bootstrap_systems_ask(user_id: int, project_id: int) -> str | None:
     titles = "; ".join(
         '"' + " ".join((n.title or "").split())[:70] + '"' for n in recent
     )
+    try:
+        standard = ", ".join(name for name, _charter in await systems_svc.standard_systems())
+    except Exception:
+        standard = ""
+    # An install whose catalog is empty still gets a usable ask — the standard
+    # names are an aid, not the point of the question.
+    standard_line = (
+        "Where an area fits a standard name, use it verbatim so it means the "
+        f"same thing in every project: {standard}. Mint freely beyond that "
+        "list — the duplicate gate guards sprawl. "
+    ) if standard else "The duplicate gate guards sprawl. "
     return (
         f"This project has {total} records and NO Systems modelled — none of "
         "them can be tagged to an area, so recurring problem-spots stay "
@@ -74,10 +85,8 @@ async def bootstrap_systems_ask(user_id: int, project_id: int) -> str | None:
         "asking permission — creating Systems is your call, not an approval "
         f"flow. From the areas the records themselves name (recent: {titles}), "
         "create_system 3-6 Systems, each with a one-paragraph charter, then "
-        "tag this record (system_ids=[...]). Where an area fits a standard "
-        f"name, use it verbatim so it means the same thing in every project: "
-        f"{', '.join(_STANDARD_SYSTEMS)}. Mint freely beyond that list — the "
-        "duplicate gate guards sprawl. This ask repeats until the first "
+        f"tag this record (system_ids=[...]). {standard_line}"
+        "This ask repeats until the first "
         "System exists; answering it once retires it for every future record."
     )
 
@@ -322,6 +331,64 @@ async def delete_system(system_id: int) -> dict:
     return {"message": f"System {system_id} deleted."}
 
 
+async def list_canonical_systems() -> dict:
+    """The GLOBAL vocabulary of area names, shared by every project.
+
+    These are the standard names to prefer when creating a System, so the same
+    word means the same thing in every project on the instance — and, from
+    milestone 307, the ids a cross-project record can point at. A project's own
+    System keeps whatever name the project calls the area; mapping it here is
+    an association, never a rename.
+
+    Reach for it before create_system when the area is an ordinary one (CI,
+    auth, storage, the API, the UI), and pass the matching `canonical_id`.
+    """
+    entries = await canonical_systems_svc.list_canonical_systems()
+    return {"canonical_systems": [e.to_dict() for e in entries]}
+
+
+async def propose_canonical_mappings(project_id: int) -> dict:
+    """Suggest a global area for each of this project's UNMAPPED Systems.
+
+    Returns PROPOSALS ONLY — nothing is written. Confirm the ones that are
+    right with map_system_to_canonical(system_id, canonical_id); ignore the
+    rest. Each carries a `basis`:
+
+    - `exact`   — the names reduce to the same match key ("CI and Release" vs
+      "CI & Release"). Safe to confirm without much thought.
+    - `overlap` — they share a meaningful word ("CI & runners" vs "CI &
+      Release"). A judgment call: confirm only if they really are the same
+      area, since a wrong mapping surfaces cross-project records in the wrong
+      place.
+
+    A System with no proposal is not a problem — unmapped is a valid resting
+    state, and a genuinely project-specific area should stay that way.
+    """
+    uid = current_user_id()
+    return {"proposals": await canonical_systems_svc.propose_mappings(uid, project_id)}
+
+
+async def map_system_to_canonical(system_id: int, canonical_id: int = 0) -> dict:
+    """Map one of a project's Systems onto a global area (or clear it).
+
+    Sets `canonical_id` and NOTHING else — the System's name, charter and every
+    record tagged to it are untouched. Pass canonical_id=0 to unmap.
+
+    Args:
+        canonical_id: id from list_canonical_systems; 0 clears the mapping.
+    """
+    uid = current_user_id()
+    system = await canonical_systems_svc.set_system_canonical(
+        uid, system_id, canonical_id or None,
+    )
+    if system is None:
+        raise ValueError(
+            f"system {system_id} not found, no write access, "
+            f"or canonical_id {canonical_id} is not a live catalog entry"
+        )
+    return system.to_dict()
+
+
 def register(mcp) -> None:
     for fn in (
         create_system,
@@ -330,5 +397,8 @@ def register(mcp) -> None:
         update_system,
         list_system_records,
         delete_system,
+        list_canonical_systems,
+        propose_canonical_mappings,
+        map_system_to_canonical,
     ):
         mcp.tool(name=fn.__name__)(fn)
diff --git a/src/scribe/models/__init__.py b/src/scribe/models/__init__.py
index 9b3d206..eb06774 100644
--- a/src/scribe/models/__init__.py
+++ b/src/scribe/models/__init__.py
@@ -46,4 +46,5 @@ 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
 from scribe.models.system import System, RecordSystem  # noqa: E402, F401
+from scribe.models.canonical_system import CanonicalSystem  # noqa: E402, F401
 from scribe.models.design_system import DesignSystem, DesignToken  # noqa: E402, F401
diff --git a/src/scribe/models/canonical_system.py b/src/scribe/models/canonical_system.py
new file mode 100644
index 0000000..a2f1acb
--- /dev/null
+++ b/src/scribe/models/canonical_system.py
@@ -0,0 +1,58 @@
+from sqlalchemy import Index, Integer, Text, text
+from sqlalchemy.orm import Mapped, mapped_column
+
+from scribe.models import Base
+from scribe.models.base import SoftDeleteMixin, TimestampMixin, iso
+
+
+class CanonicalSystem(Base, TimestampMixin, SoftDeleteMixin):
+    """A GLOBAL area name — the shared vocabulary every project's Systems
+    can point at (milestone 307, decision note 3026).
+
+    A `System` is per-project and NOT NULL on project_id, so nothing outside a
+    project can reference one: a rule that applies across projects has no way
+    to say "this is about CI" without chaining itself to one project's row.
+    This table is that join key. It carries no `user_id` on purpose — a shared
+    project must INHERIT the vocabulary rather than re-earn it, so the catalog
+    is global and the same word means the same thing in every install.
+
+    It is a convergence aid, never a gate: `systems.canonical_id` is nullable,
+    an unmapped System stays fully usable, and `record_systems` never sees this
+    table at all — the local name is a legitimate local label and is never
+    rewritten to match.
+
+    `slug` is the match key, not a display value. It folds the spelling
+    differences that produced four names for one area on the author's own
+    instance ("CI & Release" / "CI and Release" / "CI & release"): an exact slug
+    hit maps automatically, and anything short of that becomes a proposal for a
+    human to confirm. See services/canonical_systems.canonical_slug.
+    """
+
+    __tablename__ = "canonical_systems"
+
+    id: Mapped[int] = mapped_column(primary_key=True)
+    name: Mapped[str] = mapped_column(Text, nullable=False)
+    # Normalized match key — unique among LIVE rows, so a soft-deleted entry
+    # doesn't block recreating the same area (the partial-unique convention
+    # rules/topics already use).
+    slug: Mapped[str] = mapped_column(Text, nullable=False)
+    description: Mapped[str | None] = mapped_column(Text, nullable=True)
+    order_index: Mapped[int] = mapped_column(Integer, default=0, server_default="0")
+
+    __table_args__ = (
+        Index(
+            "uq_canonical_systems_slug", "slug",
+            unique=True, postgresql_where=text("deleted_at IS NULL"),
+        ),
+    )
+
+    def to_dict(self) -> dict:
+        return {
+            "id": self.id,
+            "name": self.name,
+            "slug": self.slug,
+            "description": self.description,
+            "order_index": self.order_index,
+            "created_at": iso(self.created_at),
+            "updated_at": iso(self.updated_at),
+        }
diff --git a/src/scribe/models/system.py b/src/scribe/models/system.py
index 1def12f..ddd25a7 100644
--- a/src/scribe/models/system.py
+++ b/src/scribe/models/system.py
@@ -24,6 +24,15 @@ class System(Base, TimestampMixin, SoftDeleteMixin):
         Integer, ForeignKey("projects.id", ondelete="CASCADE")
     )
     name: Mapped[str] = mapped_column(Text, default="", server_default="")
+    # The GLOBAL area this local System is an instance of (milestone 307).
+    # Nullable and SET NULL on purpose: the catalog is a convergence aid, not a
+    # gate — an unmapped System is fully usable, and retiring a canonical entry
+    # must never take a project's System with it. The local `name` is NEVER
+    # rewritten to match the canonical one; this column is the join key, and
+    # the name stays whatever the project calls the area.
+    canonical_id: Mapped[int | None] = mapped_column(
+        Integer, ForeignKey("canonical_systems.id", ondelete="SET NULL"), nullable=True
+    )
     description: Mapped[str | None] = mapped_column(Text, nullable=True)
     color: Mapped[str | None] = mapped_column(Text, nullable=True)
     # active | archived — systems accumulate; archive rather than delete.
@@ -40,6 +49,7 @@ class System(Base, TimestampMixin, SoftDeleteMixin):
             "user_id": self.user_id,
             "project_id": self.project_id,
             "name": self.name,
+            "canonical_id": self.canonical_id,
             "description": self.description,
             "color": self.color,
             "status": self.status,
diff --git a/src/scribe/routes/canonical_systems.py b/src/scribe/routes/canonical_systems.py
new file mode 100644
index 0000000..245a64b
--- /dev/null
+++ b/src/scribe/routes/canonical_systems.py
@@ -0,0 +1,93 @@
+"""Canonical-system routes — the GLOBAL area vocabulary, and the mapping of a
+project's Systems onto it (milestone 307, decision note 3026).
+
+Two shapes live here because they are two halves of one idea:
+
+- `/api/canonical-systems` — the catalog itself. Readable by any signed-in
+  user (it is shared vocabulary, not user data); writable only by an admin,
+  since a global list anyone can extend stops being a shared list.
+- the mapping endpoints — authorised by the PROJECT, because mapping writes a
+  project's own System row. The service enforces both; these are thin wrappers.
+"""
+import logging
+
+from quart import Blueprint, jsonify, request
+
+from scribe.auth import admin_required, get_current_user_id, login_required
+from scribe.routes.utils import not_found
+from scribe.services import canonical_systems as canonical_svc
+from scribe.services.projects import get_project_for_user
+
+logger = logging.getLogger(__name__)
+
+canonical_systems_bp = Blueprint("canonical_systems", __name__, url_prefix="/api")
+
+
+@canonical_systems_bp.route("/canonical-systems", methods=["GET"])
+@login_required
+async def list_canonical_systems_route():
+    entries = await canonical_svc.list_canonical_systems()
+    return jsonify({"canonical_systems": [e.to_dict() for e in entries]})
+
+
+@canonical_systems_bp.route("/canonical-systems", methods=["POST"])
+@admin_required
+async def create_canonical_system_route():
+    uid = get_current_user_id()
+    data = await request.get_json() or {}
+    if not (data.get("name") or "").strip():
+        return jsonify({"error": "name is required"}), 400
+    entry = await canonical_svc.create_canonical_system(
+        uid, data["name"], description=data.get("description"),
+    )
+    if entry is None:
+        return jsonify({"error": "Permission denied"}), 403
+    # The slug duplicate gate answers with the entry that already covers the
+    # area rather than minting a second spelling of it — 409, not a silent
+    # second row (the whole point of the table).
+    if isinstance(entry, dict):
+        return jsonify(entry), 409
+    return jsonify(entry.to_dict()), 201
+
+
+@canonical_systems_bp.route("/canonical-systems/<int:canonical_id>", methods=["PATCH"])
+@admin_required
+async def update_canonical_system_route(canonical_id: int):
+    uid = get_current_user_id()
+    data = await request.get_json() or {}
+    fields = {k: v for k, v in data.items() if k in ("name", "description", "order_index")}
+    entry = await canonical_svc.update_canonical_system(uid, canonical_id, **fields)
+    if entry is None:
+        return not_found("Canonical system")
+    return jsonify(entry.to_dict())
+
+
+@canonical_systems_bp.route(
+    "/projects/<int:project_id>/canonical-proposals", methods=["GET"]
+)
+@login_required
+async def propose_canonical_mappings_route(project_id: int):
+    """Proposals only — this endpoint writes nothing. The PUT below applies one."""
+    uid = get_current_user_id()
+    if await get_project_for_user(uid, project_id) is None:
+        return not_found("Project")
+    return jsonify({"proposals": await canonical_svc.propose_mappings(uid, project_id)})
+
+
+@canonical_systems_bp.route("/systems/<int:system_id>/canonical", methods=["PUT"])
+@login_required
+async def map_system_to_canonical_route(system_id: int):
+    """Map or unmap one System. Body: {"canonical_id": <id>|null}.
+
+    Sets that column and nothing else — no rename, no change to which records
+    are tagged to the System.
+    """
+    uid = get_current_user_id()
+    data = await request.get_json() or {}
+    canonical_id = data.get("canonical_id")
+    if canonical_id is not None and not isinstance(canonical_id, int):
+        return jsonify({"error": "canonical_id must be an integer or null"}), 400
+    system = await canonical_svc.set_system_canonical(uid, system_id, canonical_id)
+    if system is None:
+        return not_found("System or canonical system")
+    return jsonify(system.to_dict())
diff --git a/src/scribe/services/backup.py b/src/scribe/services/backup.py
index d93f47f..f4e1360 100644
--- a/src/scribe/services/backup.py
+++ b/src/scribe/services/backup.py
@@ -11,6 +11,7 @@ from scribe.models.note_supersession import NoteSupersession
 from scribe.models.note_version import NoteVersion
 from scribe.models.design_system import DesignSystem, DesignToken
 from scribe.models.note_usage import NoteUsageEvent
+from scribe.models.canonical_system import CanonicalSystem
 from scribe.models.code_shape import CodeShape, CodeShapeEvent, CodeShapeUse
 from scribe.models.project import Project
 from scribe.models.repo_binding import RepoBinding
@@ -69,6 +70,10 @@ _BACKED_UP = [
     "note_usage_events", "repo_bindings", "note_supersessions",
     # v7 (2026-08): the shape ledger (#2787); v8: its history (#2793).
     "code_shapes", "code_shape_events", "code_shape_uses",
+    # v9 (2026-08): the global area catalog (milestone 307). Global, not
+    # user-scoped, so it rides in EVERY export — including a single-user
+    # one, whose Systems would otherwise restore unmapped.
+    "canonical_systems",
 ]
 
 # Tables intentionally NOT in the backup, surfaced in the payload so the gap is
@@ -127,12 +132,29 @@ def _rulebook_exclusion_rows(rows) -> list[dict]:
 # same reason: CI has no database, so a serialiser that is a plain function is
 # one that can actually be tested.
 
-def _system_rows(rows) -> list[dict]:
+def _canonical_system_rows(rows) -> list[dict]:
+    """The global area catalog. Carried WITHOUT ids: a restore matches on slug,
+    so a target install that already seeded the standard vocabulary reuses its
+    own rows and only gains the entries an admin added here."""
+    return [
+        {
+            "name": r.name, "slug": r.slug, "description": r.description,
+            "order_index": r.order_index,
+        }
+        for r in rows
+    ]
+
+
+def _system_rows(rows, canonical_slugs: dict[int, str]) -> list[dict]:
+    """A project's Systems. The canonical mapping travels as a SLUG, not an id
+    — the catalog is global and its ids are per-install, so an id would restore
+    pointing at whatever area happened to land on that number."""
     return [
         {
             "id": r.id, "user_id": r.user_id, "project_id": r.project_id,
             "name": r.name, "description": r.description, "color": r.color,
             "status": r.status, "order_index": r.order_index,
+            "canonical_slug": canonical_slugs.get(r.canonical_id or 0),
         }
         for r in rows
     ]
@@ -363,6 +385,10 @@ async def export_full_backup() -> dict:
         )).scalars().all()
         settings = (await session.execute(select(Setting))).scalars().all()
         systems = (await session.execute(select(System))).scalars().all()
+        canonical_systems = (await session.execute(
+            select(CanonicalSystem).where(CanonicalSystem.deleted_at.is_(None))
+            .order_by(CanonicalSystem.order_index)
+        )).scalars().all()
         record_systems = (await session.execute(select(RecordSystem))).scalars().all()
         supersessions = (
             await session.execute(select(NoteSupersession))
@@ -424,7 +450,10 @@ async def export_full_backup() -> dict:
         "rule_suppressions": _rule_suppression_rows(rule_suppressions),
         "topic_suppressions": _topic_suppression_rows(topic_suppressions),
         "rulebook_exclusions": _rulebook_exclusion_rows(rulebook_exclusions),
-        "systems": _system_rows(systems),
+        "canonical_systems": _canonical_system_rows(canonical_systems),
+        "systems": _system_rows(
+            systems, {c.id: c.slug for c in canonical_systems}
+        ),
         "record_systems": _record_system_rows(record_systems),
         "design_systems": _design_system_rows(design_systems),
         "design_tokens": _design_token_rows(design_tokens),
@@ -467,6 +496,12 @@ async def export_user_backup(user_id: int) -> dict:
         systems = (await session.execute(
             select(System).where(System.user_id == user_id)
         )).scalars().all()
+        # Global: taken whole even in a per-user export, because the Systems
+        # above reference it and a partial catalog restores partial mappings.
+        canonical_systems = (await session.execute(
+            select(CanonicalSystem).where(CanonicalSystem.deleted_at.is_(None))
+            .order_by(CanonicalSystem.order_index)
+        )).scalars().all()
         system_ids = [sy.id for sy in systems]
         note_ids = [n.id for n in notes]
         # Scoped by the user's SYSTEMS, not their notes: a shared note carrying
@@ -583,7 +618,10 @@ async def export_user_backup(user_id: int) -> dict:
         "rule_suppressions": _rule_suppression_rows(rule_suppressions),
         "topic_suppressions": _topic_suppression_rows(topic_suppressions),
         "rulebook_exclusions": _rulebook_exclusion_rows(rulebook_exclusions),
-        "systems": _system_rows(systems),
+        "canonical_systems": _canonical_system_rows(canonical_systems),
+        "systems": _system_rows(
+            systems, {c.id: c.slug for c in canonical_systems}
+        ),
         "record_systems": _record_system_rows(record_systems),
         "design_systems": _design_system_rows(design_systems),
         "design_tokens": _design_token_rows(design_tokens),
@@ -697,7 +735,7 @@ async def _restore_v2(data: dict) -> dict:
         "systems": 0, "record_systems": 0, "design_systems": 0,
         "design_tokens": 0, "note_usage_events": 0, "repo_bindings": 0,
         "note_supersessions": 0, "code_shapes": 0, "code_shape_events": 0,
-        "code_shape_uses": 0,
+        "code_shape_uses": 0, "canonical_systems": 0,
     }
 
     async with async_session() as session:
@@ -972,6 +1010,31 @@ async def _restore_v2(data: dict) -> dict:
 
         # 15. Systems
         system_id_map: dict[int, int] = {}
+        # 14b. The global area catalog, matched on SLUG. This install already
+        # has the standard vocabulary from its migrations, so the common case
+        # adds nothing and simply learns which local id each slug is; only an
+        # entry an admin added on the source instance is created here. Runs
+        # BEFORE systems, which resolve their mapping through this map.
+        canonical_id_by_slug: dict[str, int] = {}
+        existing_canonical = (await session.execute(
+            select(CanonicalSystem).where(CanonicalSystem.deleted_at.is_(None))
+        )).scalars().all()
+        for entry in existing_canonical:
+            canonical_id_by_slug[entry.slug] = entry.id
+        for cs_data in data.get("canonical_systems", []):
+            slug = cs_data.get("slug") or ""
+            if not slug or slug in canonical_id_by_slug:
+                continue
+            entry = CanonicalSystem(
+                name=cs_data.get("name", ""), slug=slug,
+                description=cs_data.get("description"),
+                order_index=cs_data.get("order_index", 0),
+            )
+            session.add(entry)
+            await session.flush()
+            canonical_id_by_slug[slug] = entry.id
+            stats["canonical_systems"] += 1
+
         for sy_data in data.get("systems", []):
             mapped_uid = user_id_map.get(sy_data.get("user_id", 0))
             mapped_pid = project_id_map.get(sy_data.get("project_id", 0))
@@ -984,6 +1047,9 @@ async def _restore_v2(data: dict) -> dict:
                 color=sy_data.get("color"),
                 status=sy_data.get("status", "active"),
                 order_index=sy_data.get("order_index", 0),
+                # An unknown slug restores UNMAPPED rather than failing: the
+                # System and its records are the payload, the mapping is an aid.
+                canonical_id=canonical_id_by_slug.get(sy_data.get("canonical_slug") or ""),
             )
             session.add(system)
             await session.flush()
diff --git a/src/scribe/services/canonical_systems.py b/src/scribe/services/canonical_systems.py
new file mode 100644
index 0000000..56088c1
--- /dev/null
+++ b/src/scribe/services/canonical_systems.py
@@ -0,0 +1,256 @@
+"""The global canonical area vocabulary, and the mapping from a project's
+Systems onto it (milestone 307 step 1, decision note 3026).
+
+A `System` is per-project. Nothing outside a project can reference one, so a
+rule that spans projects has no way to say "this is about CI" without chaining
+itself to one project's row. `CanonicalSystem` is that join key, and it is
+GLOBAL — no `user_id`, so a shared project inherits the vocabulary instead of
+re-earning it.
+
+Two rules govern everything here:
+
+- **Associate, never rewrite.** Mapping a System sets `systems.canonical_id`
+  and nothing else. The local name stays whatever the project calls the area,
+  and `record_systems` is never touched — no record's tags move.
+- **Propose, never decide.** An exact slug hit is mechanical and maps on
+  request; anything short of that is a PROPOSAL a human confirms. "CI &
+  Release" vs "CI & runners" is a judgment call, and the cost of guessing it
+  wrong silently is a rule surfacing in the wrong project.
+
+Reads are open to any authenticated caller (the catalog is shared vocabulary,
+not user data). Writes to the catalog itself are admin-only: a global table
+that anyone can extend is how a shared vocabulary stops being shared.
+"""
+import logging
+import re
+from datetime import datetime, timezone
+
+from sqlalchemy import select
+
+from scribe.models import async_session
+from scribe.models.canonical_system import CanonicalSystem
+from scribe.models.system import System
+from scribe.models.user import User
+from scribe.services import access
+
+logger = logging.getLogger(__name__)
+
+# Tokens that carry no meaning for matching — "&" becomes "and" before the
+# split, so it would otherwise dominate the overlap score of every pair.
+_NOISE_TOKENS = frozenset({"and", "the", "a", "of"})
+
+_NON_ALNUM = re.compile(r"[^a-z0-9]+")
+
+
+def canonical_slug(name: str) -> str:
+    """The match key for an area name — NOT a display value.
+
+    Folds exactly the spelling differences that produced three names for one
+    area on the author's instance: `CI & Release`, `CI and Release` and
+    `CI & release` all slug to `ci-and-release`, so they map mechanically.
+    A real difference survives: `CI & runners` slugs to `ci-and-runners` and
+    goes through the proposal path where a human decides.
+    """
+    lowered = name.strip().lower().replace("&", " and ")
+    return "-".join(_NON_ALNUM.sub(" ", lowered).split())
+
+
+def _tokens(slug: str) -> frozenset[str]:
+    return frozenset(slug.split("-")) - _NOISE_TOKENS
+
+
+async def _is_admin(user_id: int) -> bool:
+    async with async_session() as session:
+        role = await session.scalar(select(User.role).where(User.id == user_id))
+    return role == "admin"
+
+
+async def list_canonical_systems() -> list[CanonicalSystem]:
+    """The whole catalog, in display order. Global — no ownership filter."""
+    async with async_session() as session:
+        result = await session.execute(
+            select(CanonicalSystem)
+            .where(CanonicalSystem.deleted_at.is_(None))
+            .order_by(CanonicalSystem.order_index.asc(), CanonicalSystem.name.asc())
+        )
+        return list(result.scalars().all())
+
+
+async def get_canonical_system(canonical_id: int) -> CanonicalSystem | None:
+    async with async_session() as session:
+        entry = await session.get(CanonicalSystem, canonical_id)
+    return entry if entry is not None and entry.deleted_at is None else None
+
+
+async def find_by_name(name: str) -> CanonicalSystem | None:
+    """The exact-slug lookup — the mechanical half of matching."""
+    slug = canonical_slug(name)
+    if not slug:
+        return None
+    async with async_session() as session:
+        return await session.scalar(
+            select(CanonicalSystem).where(
+                CanonicalSystem.slug == slug,
+                CanonicalSystem.deleted_at.is_(None),
+            )
+        )
+
+
+async def create_canonical_system(
+    user_id: int, name: str, description: str | None = None,
+) -> CanonicalSystem | dict | None:
+    """Add an area to the global catalog. Admin only.
+
+    Duplicate-gated on the SLUG, not the raw name, so "CI and Release" cannot
+    be added alongside "CI & Release" — that is the drift this table exists to
+    end. Returns the existing entry's id instead of creating a second one.
+    """
+    if not await _is_admin(user_id):
+        return None
+    slug = canonical_slug(name)
+    if not slug:
+        return None
+    existing = await find_by_name(name)
+    if existing is not None:
+        return {
+            "duplicate": True,
+            "existing_id": existing.id,
+            "message": (
+                f"'{existing.name}' (#{existing.id}) already covers this area — "
+                f"both names reduce to '{slug}'. Map Systems to it, or "
+                "update_canonical_system if the charter needs revising."
+            ),
+        }
+    async with async_session() as session:
+        highest = await session.scalar(
+            select(CanonicalSystem.order_index)
+            .order_by(CanonicalSystem.order_index.desc())
+            .limit(1)
+        )
+        entry = CanonicalSystem(
+            name=" ".join(name.split()),
+            slug=slug,
+            description=description,
+            order_index=(highest or 0) + 1,
+        )
+        session.add(entry)
+        await session.commit()
+        await session.refresh(entry)
+        return entry
+
+
+async def update_canonical_system(
+    user_id: int, canonical_id: int, **fields: object,
+) -> CanonicalSystem | None:
+    """Rename or re-charter a catalog entry. Admin only.
+
+    A rename recomputes the slug — the display name and the match key must not
+    be allowed to disagree, or the exact-match path silently stops finding it.
+    """
+    if not await _is_admin(user_id):
+        return None
+    allowed = {"name", "description", "order_index"}
+    async with async_session() as session:
+        entry = await session.get(CanonicalSystem, canonical_id)
+        if entry is None or entry.deleted_at is not None:
+            return None
+        for key, value in fields.items():
+            if key in allowed and value is not None:
+                setattr(entry, key, value)
+        if "name" in fields and fields["name"]:
+            entry.name = " ".join(str(fields["name"]).split())
+            entry.slug = canonical_slug(entry.name)
+        entry.updated_at = datetime.now(timezone.utc)
+        await session.commit()
+        await session.refresh(entry)
+        return entry
+
+
+async def set_system_canonical(
+    user_id: int, system_id: int, canonical_id: int | None,
+) -> System | None:
+    """Map (or unmap) one project System onto a catalog entry.
+
+    Authorised by the PROJECT, not the catalog: mapping changes the project's
+    row, so project write access is the right gate (rule 78 — never a bare
+    owner filter). Passing None clears the mapping.
+
+    Touches `canonical_id` and nothing else — the System's own name, charter
+    and record associations are left exactly as they are.
+    """
+    if canonical_id is not None and await get_canonical_system(canonical_id) is None:
+        return None
+    async with async_session() as session:
+        system = await session.get(System, system_id)
+        if system is None or system.deleted_at is not None:
+            return None
+        if not await access.can_write_project(user_id, system.project_id):
+            return None
+        system.canonical_id = canonical_id
+        system.updated_at = datetime.now(timezone.utc)
+        await session.commit()
+        await session.refresh(system)
+        return system
+
+
+async def propose_mappings(user_id: int, project_id: int) -> list[dict]:
+    """Suggest a catalog entry for each of a project's UNMAPPED Systems.
+
+    Returns proposals, never applied changes — `set_system_canonical` is the
+    only thing that writes. Each carries a `basis` so the reviewer knows what
+    they are approving:
+
+    - `exact`   — the two names reduce to the same slug. Mechanical.
+    - `overlap` — they share a meaningful word ("CI & runners" / "CI &
+      Release"). A judgment call, and the reason this is a proposal at all.
+
+    A System with no plausible match simply gets no proposal: unmapped is a
+    perfectly good resting state, so silence here is an answer, not a gap.
+    """
+    if not await access.can_read_project(user_id, project_id):
+        return []
+    catalog = await list_canonical_systems()
+    if not catalog:
+        return []
+    async with async_session() as session:
+        result = await session.execute(
+            select(System).where(
+                System.project_id == project_id,
+                System.canonical_id.is_(None),
+                System.deleted_at.is_(None),
+            ).order_by(System.order_index.asc(), System.created_at.asc())
+        )
+        systems = list(result.scalars().all())
+
+    by_slug = {entry.slug: entry for entry in catalog}
+    proposals: list[dict] = []
+    for system in systems:
+        slug = canonical_slug(system.name)
+        if not slug:
+            continue
+        exact = by_slug.get(slug)
+        if exact is not None:
+            match, basis, score = exact, "exact", 1.0
+        else:
+            local = _tokens(slug)
+            scored = [
+                (len(local & _tokens(entry.slug)) / max(len(local | _tokens(entry.slug)), 1), entry)
+                for entry in catalog
+            ]
+            # Any shared meaningful word is enough to ASK. The threshold is
+            # deliberately generous because a wrong proposal costs one click
+            # and a missing one costs a mapping nobody thinks to make again.
+            best_score, best = max(scored, key=lambda pair: pair[0])
+            if best_score <= 0:
+                continue
+            match, basis, score = best, "overlap", round(best_score, 3)
+        proposals.append({
+            "system_id": system.id,
+            "system_name": system.name,
+            "canonical_id": match.id,
+            "canonical_name": match.name,
+            "basis": basis,
+            "score": score,
+        })
+    proposals.sort(key=lambda p: (-p["score"], p["system_name"]))
+    return proposals
diff --git a/src/scribe/services/systems.py b/src/scribe/services/systems.py
index e72b2b6..2034363 100644
--- a/src/scribe/services/systems.py
+++ b/src/scribe/services/systems.py
@@ -14,38 +14,39 @@ from scribe.models import async_session
 from scribe.models.note import Note
 from scribe.models.system import RecordSystem, System
 from scribe.services import access
+from scribe.services import canonical_systems as canonical_systems_svc
 
 logger = logging.getLogger(__name__)
 
 
-# The standard cross-project vocabulary (#2798): names that mean the same
-# thing in every project, so a starter set reads the same everywhere. The
-# bootstrap ask (mcp/tools/systems) names them; the inception seed
-# (services/inception, milestone 297) mints them. Charters are deliberately
-# generic — a project refines them as its own records accrue.
-STANDARD_SYSTEMS: tuple[tuple[str, str], ...] = (
-    ("CI & Release", "How the project is verified and shipped: pipelines, runners, image/artifact builds, release tagging and rollback."),
-    ("Auth & Access", "Who may do what: identity, sessions/tokens, permissions and the scoping of every read and write to the right users."),
-    ("Data Model & Storage", "What is stored and how it is shaped: the schema, migrations, serialisation and the services that own a table's lifecycle."),
-    ("API Surface", "The doors into the capability: HTTP routes, tool/RPC surfaces, request parsing, error envelopes and their contracts."),
-    ("UI & Design", "What people see and touch: views, components, client state, and the design tokens/recipes they are built from."),
-    ("Import & Export", "Data crossing the boundary: backups, exports, imports, sync with other systems, file formats."),
-    ("Background Jobs", "Work that runs without a request: schedulers, queues, periodic ticks, retention and maintenance."),
-    ("Observability", "How the system reports on itself: logging, metrics, audit trails, health and diagnostics."),
-)
+async def standard_systems() -> list[tuple[str, str]]:
+    """The standard cross-project vocabulary (#2798) as (name, charter) pairs.
+
+    Reads the GLOBAL canonical catalog (milestone 307). This was a tuple
+    constant in this module until the catalog became a table: a constant
+    cannot be a foreign key, so nothing outside a project could reference an
+    area, and the list only ever applied on the inception-seed path — which is
+    how three spellings of "CI & Release" reached one instance anyway.
+    """
+    return [(entry.name, entry.description or "") for entry in
+            await canonical_systems_svc.list_canonical_systems()]
 
 
 async def seed_standard_systems(user_id: int, project_id: int) -> list[System]:
     """Mint the standard starter set for a project that has NO Systems yet
     (milestone 297). Idempotent: a project with any System — the vocabulary
     already started, standard or not — gets nothing; the duplicate gate and
-    the project's own judgment take it from there. [] without write access."""
+    the project's own judgment take it from there. [] without write access.
+
+    Seeded Systems are mapped to their catalog entry as they are created, so a
+    project born this way needs no reconciliation pass later."""
     if await list_systems(user_id, project_id, include_archived=True):
         return []
     out: list[System] = []
-    for index, (name, charter) in enumerate(STANDARD_SYSTEMS):
+    for index, entry in enumerate(await canonical_systems_svc.list_canonical_systems()):
         system = await create_system(
-            user_id, project_id, name, description=charter, order_index=index,
+            user_id, project_id, entry.name, description=entry.description,
+            order_index=index, canonical_id=entry.id,
         )
         if system is None:
             break
@@ -60,8 +61,14 @@ async def create_system(
     description: str | None = None,
     color: str | None = None,
     order_index: int = 0,
+    canonical_id: int | None = None,
 ) -> System | None:
-    """Create a System. None if the user can't write the project."""
+    """Create a System. None if the user can't write the project.
+
+    `canonical_id` maps the new System onto the global catalog; leaving it None
+    is fine — an unmapped System is fully usable, and the mapping can be
+    proposed later (services/canonical_systems.propose_mappings).
+    """
     if not await access.can_write_project(user_id, project_id):
         return None
     async with async_session() as session:
@@ -72,6 +79,7 @@ async def create_system(
             description=description,
             color=color,
             order_index=order_index,
+            canonical_id=canonical_id,
         )
         session.add(system)
         await session.commit()
@@ -110,6 +118,10 @@ async def list_systems(
 
 async def update_system(user_id: int, system_id: int, **fields: object) -> System | None:
     """Update a System if the user can write its project."""
+    # canonical_id is deliberately NOT settable here: canonical_systems.
+    # set_system_canonical is its single writer, because it also validates the
+    # catalog entry is live. Two entry points onto one column is the drift this
+    # table exists to end.
     allowed = {"name", "description", "color", "status", "order_index"}
     async with async_session() as session:
         system = await session.get(System, system_id)
diff --git a/tests/test_inception.py b/tests/test_inception.py
index 75e44e7..becf8ca 100644
--- a/tests/test_inception.py
+++ b/tests/test_inception.py
@@ -57,9 +57,22 @@ def test_normalize_choices_is_canonical_and_complete():
                                        "design_system_id": None, "seed_systems": False}
 
 
-def test_standard_systems_vocabulary_is_one_list_for_ask_and_seed():
-    from scribe.mcp.tools.systems import _STANDARD_SYSTEMS
-    from scribe.services.systems import STANDARD_SYSTEMS
-    assert _STANDARD_SYSTEMS == tuple(n for n, _ in STANDARD_SYSTEMS)
-    assert len(STANDARD_SYSTEMS) == 8 and all(charter for _, charter in STANDARD_SYSTEMS)
+def test_standard_systems_vocabulary_reads_the_catalog_not_a_constant():
+    """The vocabulary moved from a module constant to the global catalog table
+    (milestone 307): a constant cannot be a foreign key, so nothing outside a
+    project could reference an area. The seed and the bootstrap ask must both
+    read the table, or the list they show and the list they mint diverge."""
+    import inspect
+
+    from scribe.services import systems as systems_svc
+
+    assert not hasattr(systems_svc, "STANDARD_SYSTEMS"), (
+        "the constant is gone — the catalog table is the single source"
+    )
+    source = inspect.getsource(systems_svc.seed_standard_systems)
+    assert "list_canonical_systems" in source
+    assert "canonical_id=entry.id" in source, (
+        "a seeded System must be mapped as it is created, or a project born "
+        "from the standard set still needs a reconciliation pass"
+    )
 
diff --git a/tests/test_integration_inception.py b/tests/test_integration_inception.py
index 51ecedc..a46e4db 100644
--- a/tests/test_integration_inception.py
+++ b/tests/test_integration_inception.py
@@ -13,6 +13,7 @@ from scribe.models.project import Project
 from scribe.models.rulebook import Rulebook
 from scribe.services import inception as inception_svc
 from scribe.services import rulebooks as rulebooks_svc
+from scribe.services import canonical_systems as canonical_svc
 from scribe.services import systems as systems_svc
 from tests.helpers import ensure_user
 
@@ -62,7 +63,11 @@ async def test_decide_applies_every_effect_and_records_last(seeded):
     })
     assert out["effects"]["excluded"] == [seeded["always"]]
     assert out["effects"]["subscribed"] == [seeded["other"]]
-    assert len(out["effects"]["systems_seeded"]) == len(systems_svc.STANDARD_SYSTEMS)
+    catalog = await canonical_svc.list_canonical_systems()
+    assert len(out["effects"]["systems_seeded"]) == len(catalog)
+    # Seeded Systems come out mapped, not needing a later reconciliation.
+    seeded_systems = await systems_svc.list_systems(owner, pid)
+    assert all(s.canonical_id is not None for s in seeded_systems)
 
     # The exclusion is total: the project's always-on set is empty, the
     # departure is named, the subscription binds.
@@ -81,7 +86,7 @@ async def test_decide_applies_every_effect_and_records_last(seeded):
     # Re-deciding with seed again mints nothing twice; include reverses the exclusion.
     again = await inception_svc.decide(owner, pid, via="ui", choices={"seed_systems": True})
     assert again["effects"]["systems_seeded"] == []
-    assert len(await systems_svc.list_systems(owner, pid)) == len(systems_svc.STANDARD_SYSTEMS)
+    assert len(await systems_svc.list_systems(owner, pid)) == len(catalog)
     await rulebooks_svc.include_always_on_rulebook_for_project(pid, seeded["always"], owner)
     assert [r.title for r in await rulebooks_svc.list_always_on_rules(owner, project_id=pid)] == ["dev is home"]
 
diff --git a/tests/test_services_canonical_systems.py b/tests/test_services_canonical_systems.py
new file mode 100644
index 0000000..53b12ed
--- /dev/null
+++ b/tests/test_services_canonical_systems.py
@@ -0,0 +1,64 @@
+"""The canonical-slug matcher — the line between what maps mechanically and
+what a human is asked to confirm (milestone 307, note 3026).
+
+These cases are the real drift found across the author's own instance: one area
+carrying three spellings, and two areas that LOOK alike and are not the same.
+Getting the boundary wrong in either direction is a silent failure — a missed
+mapping nobody thinks to make again, or a cross-project record surfacing in the
+wrong project.
+"""
+import pytest
+
+from scribe.services.canonical_systems import canonical_slug
+
+
+@pytest.mark.parametrize("name", ["CI & Release", "CI and Release", "CI & release",
+                                  "  ci   and   release  "])
+def test_spelling_variants_of_one_area_collapse_to_one_key(name):
+    """Case, spacing, punctuation and "&" vs "and" are not real differences.
+    All three of the first spellings were live in different projects at once."""
+    assert canonical_slug(name) == "ci-and-release"
+
+
+@pytest.mark.parametrize("name,expected", [
+    ("Auth & Access", "auth-and-access"),
+    ("Data Model & Storage", "data-model-and-storage"),
+    ("UI & Design", "ui-and-design"),
+    ("Background Jobs", "background-jobs"),
+    ("Observability", "observability"),
+])
+def test_the_seeded_vocabulary_slugs_match_the_migration(name, expected):
+    """Migration 0087 writes these slugs literally. If the function and the
+    migration disagree, every seeded entry becomes unreachable by exact match
+    and every mapping silently degrades to a proposal."""
+    assert canonical_slug(name) == expected
+
+
+@pytest.mark.parametrize("a,b", [
+    ("CI & Release", "CI & runners"),
+    ("Auth & Access", "Auth & Accounts"),
+    ("UI & Design", "Frontend (Vue app)"),
+    ("UI & Design", "Web Shell and Theme"),
+])
+def test_genuinely_different_names_do_not_collapse(a, b):
+    """These pairs may or may not be the same area — that is a judgment call,
+    so they must NOT map automatically. They reach the operator as proposals."""
+    assert canonical_slug(a) != canonical_slug(b)
+
+
+def test_a_nameless_system_yields_no_key():
+    """An empty slug is the one value callers must special-case: two unnameable
+    Systems must not map onto each other. Both propose_mappings and find_by_name
+    bail on a falsy slug for this reason."""
+    assert canonical_slug("") == ""
+    assert canonical_slug("   ") == ""
+    assert canonical_slug("---") == ""
+
+
+def test_a_punctuation_separator_is_not_read_as_the_word_and():
+    """"CI/Release" is a real spelling and it does NOT collapse onto
+    "CI & Release" — only "&" carries that meaning. It still reaches the
+    operator through the overlap path, where both words match; what it must not
+    do is map itself silently."""
+    assert canonical_slug("CI/Release") == "ci-release"
+    assert canonical_slug("CI/Release") != canonical_slug("CI & Release")