diff --git a/backend/migrations/027_projects_runtime_config.sql b/backend/migrations/027_projects_runtime_config.sql
new file mode 100644
index 0000000..937d792
--- /dev/null
+++ b/backend/migrations/027_projects_runtime_config.sql
@@ -0,0 +1,31 @@
+-- §22 M3 (Plan A) — additive registry/runtime-config schema.
+--
+-- This is the additive half of M3's backend. It adds the project `type` and
+-- `initial_state` columns (mirrored from the registry), the deployment
+-- singleton (deployment name/tagline mirrored from the registry), and the
+-- §22.4c review columns on cached_rfcs. NO table rebuilds: the §22.13 PK
+-- rebuilds and the default->slug re-stamp ride a later migration (Plan B),
+-- just before a second project can collide (see migration 026's DEFERRED
+-- block and docs/superpowers/specs/2026-06-03-m3-backend-design.md §1/§6).
+
+ALTER TABLE projects ADD COLUMN type TEXT NOT NULL DEFAULT 'document'
+    CHECK (type IN ('document', 'specification', 'bdd'));
+ALTER TABLE projects ADD COLUMN initial_state TEXT NOT NULL DEFAULT 'super-draft'
+    CHECK (initial_state IN ('super-draft', 'active'));
+
+-- Deployment-level identity (name, tagline) mirrored from the registry's
+-- `deployment:` block. A singleton: the CHECK pins it to one row.
+CREATE TABLE IF NOT EXISTS deployment (
+    id           INTEGER PRIMARY KEY CHECK (id = 1),
+    name         TEXT,
+    tagline      TEXT,
+    registry_sha TEXT,
+    updated_at   TEXT NOT NULL DEFAULT (datetime('now'))
+);
+INSERT OR IGNORE INTO deployment (id) VALUES (1);
+
+-- §22.4c review flag + provenance. unreviewed is git-truth (mirrored from
+-- entry frontmatter); it survives a cache rebuild like `state` does.
+ALTER TABLE cached_rfcs ADD COLUMN unreviewed INTEGER NOT NULL DEFAULT 0;
+ALTER TABLE cached_rfcs ADD COLUMN reviewed_at TEXT;
+ALTER TABLE cached_rfcs ADD COLUMN reviewed_by TEXT;
diff --git a/backend/tests/test_migration_027.py b/backend/tests/test_migration_027.py
new file mode 100644
index 0000000..91ad565
--- /dev/null
+++ b/backend/tests/test_migration_027.py
@@ -0,0 +1,54 @@
+"""Migration 027 — additive §22 M3 schema (projects.type/initial_state, the
+deployment singleton, cached_rfcs review columns). No table rebuilds in Plan A."""
+from __future__ import annotations
+
+import tempfile
+from pathlib import Path
+
+from app import db
+from app.config import Config
+
+
+def _fresh_config() -> Config:
+    tmp = Path(tempfile.mkdtemp(prefix="mig027-")) / "t.db"
+    return Config(
+        gitea_url="x", gitea_bot_user="x", gitea_bot_token="x", gitea_org="x",
+        meta_repo="meta", registry_repo="registry",
+        oauth_client_id="x", oauth_client_secret="x", app_url="x",
+        secret_key="x", database_path=tmp, owner_gitea_login="x",
+        webhook_secret="x",
+    )
+
+
+def test_027_adds_project_type_and_initial_state():
+    cfg = _fresh_config()
+    db.run_migrations(cfg)
+    conn = db.connect(cfg.database_path)
+    cols = {r["name"]: r for r in conn.execute("PRAGMA table_info(projects)")}
+    assert "type" in cols and cols["type"]["dflt_value"] == "'document'"
+    assert "initial_state" in cols and cols["initial_state"]["dflt_value"] == "'super-draft'"
+    conn.close()
+
+
+def test_027_creates_deployment_singleton():
+    cfg = _fresh_config()
+    db.run_migrations(cfg)
+    conn = db.connect(cfg.database_path)
+    rows = list(conn.execute("SELECT id FROM deployment"))
+    assert [r["id"] for r in rows] == [1]
+    try:
+        conn.execute("INSERT INTO deployment (id) VALUES (2)")
+        raised = False
+    except Exception:
+        raised = True
+    assert raised
+    conn.close()
+
+
+def test_027_adds_review_columns_to_cached_rfcs():
+    cfg = _fresh_config()
+    db.run_migrations(cfg)
+    conn = db.connect(cfg.database_path)
+    cols = {r["name"] for r in conn.execute("PRAGMA table_info(cached_rfcs)")}
+    assert {"unreviewed", "reviewed_at", "reviewed_by"} <= cols
+    conn.close()