diff --git a/tooling/planet-gen/atlas_common.py b/tooling/planet-gen/atlas_common.py
new file mode 100644
index 000000000..10dee9241
--- /dev/null
+++ b/tooling/planet-gen/atlas_common.py
@@ -0,0 +1,164 @@
+#!/usr/bin/env python3
+"""
+atlas_common.py — shared atlas-DB utilities for the planet-gen importers.
+
+Extracted from the retired generate_atlas.py (D-223, #951). The atlas city/road/
+river geometry *generator* was retired when authored geometry was dropped in
+favour of the deterministic server-side cascade (Phase 4); markers.json is now a
+flavoured name pool only. What remained were the schema/DB helpers shared by the
+surviving build-time importers (heightmaps, province boundaries, city names) and
+the naming pipeline. Those live here so there is a single home for them with no
+dependency on the deleted geometry-production code.
+
+This is a library module — it does NOT re-exec the venv. The importing scripts
+(import_heightmaps.py, import_province_boundaries.py, import_city_names.py,
+gemma_naming.py) own the venv bootstrap before importing this module.
+
+Decisions: D-223 (authored content as flavoured name pool), D-191 (atlas index).
+"""
+
+import sqlite3
+from pathlib import Path
+
+import yaml
+
+# ---------------------------------------------------------------------------
+# Paths and grid constants
+# ---------------------------------------------------------------------------
+TOOLING_DIR = Path(__file__).resolve().parent
+REPO_ROOT = (TOOLING_DIR / ".." / "..").resolve()
+
+DB_PATH = REPO_ROOT / "server" / "data" / "systems.db"
+WIKI_SYSTEMS = REPO_ROOT / "wiki" / "star-systems"
+SYSTEMS_SCHEMA_PATH = REPO_ROOT / "server" / "data" / "systems-schema.sql"
+
+# Heightmap pixel-space grid (D-202). Geometry derives from this resolution.
+GRID_W = 512
+GRID_H = 256
+
+# Delimiters for the single canonical atlas_* DDL block in
+# server/data/systems-schema.sql. `_load_atlas_schema()` extracts everything
+# between these markers at runtime so this file does not duplicate the schema
+# (and drift from it).
+_ATLAS_SCHEMA_BEGIN_MARKER = "-- BEGIN ATLAS INDEX"
+_ATLAS_SCHEMA_END_MARKER = "-- END ATLAS INDEX"
+
+
+# ---------------------------------------------------------------------------
+# Schema
+# ---------------------------------------------------------------------------
+
+def _load_atlas_schema() -> str:
+    """Return the atlas_* DDL block from systems-schema.sql.
+
+    systems-schema.sql is the single source of truth for the atlas index
+    tables (see the BEGIN ATLAS INDEX / END ATLAS INDEX markers). We extract
+    just that block and run it through `executescript` so callers work against
+    any DB state (fresh or partially-migrated) without maintaining a second
+    copy of the DDL here.
+    """
+    if not SYSTEMS_SCHEMA_PATH.exists():
+        raise RuntimeError(
+            f"systems-schema.sql not found at {SYSTEMS_SCHEMA_PATH} — "
+            "atlas importers cannot proceed without the canonical schema."
+        )
+    text = SYSTEMS_SCHEMA_PATH.read_text()
+    try:
+        start = text.index(_ATLAS_SCHEMA_BEGIN_MARKER)
+        end = text.index(_ATLAS_SCHEMA_END_MARKER, start)
+    except ValueError as e:
+        raise RuntimeError(
+            f"systems-schema.sql is missing the {_ATLAS_SCHEMA_BEGIN_MARKER}/"
+            f"{_ATLAS_SCHEMA_END_MARKER} block — has the schema been "
+            "restructured?"
+        ) from e
+    return text[start:end]
+
+
+def ensure_atlas_schema(conn: sqlite3.Connection) -> None:
+    """Apply the canonical atlas_* DDL from systems-schema.sql.
+
+    Idempotent: all statements inside the block use CREATE TABLE / INDEX
+    IF NOT EXISTS, so running this on an already-migrated DB is a no-op.
+
+    Also ensures the meta stamp table exists (#855, #856).
+    """
+    conn.executescript(_load_atlas_schema())
+    conn.executescript(
+        """
+        CREATE TABLE IF NOT EXISTS meta (
+            generator_name TEXT PRIMARY KEY,
+            schema_version TEXT NOT NULL,
+            schema_sha TEXT,
+            generator_sha TEXT NOT NULL,
+            generated_at TEXT NOT NULL DEFAULT (datetime('now'))
+        );
+        """
+    )
+    # Add schema_sha column to existing DBs that pre-date #888 (#888 migration).
+    try:
+        conn.execute("ALTER TABLE meta ADD COLUMN schema_sha TEXT")
+    except sqlite3.OperationalError as e:
+        if "duplicate column" not in str(e).lower():
+            raise
+
+
+# ---------------------------------------------------------------------------
+# Body definition loading
+# ---------------------------------------------------------------------------
+
+def load_body_def(body_dir: Path) -> dict | None:
+    """Load body definition from body index.md frontmatter."""
+    index_md = body_dir / "index.md"
+    if not index_md.exists():
+        return None
+    content = index_md.read_text()
+    if not content.startswith("---"):
+        return None
+    try:
+        end = content.index("---", 3)
+        bd = yaml.safe_load(content[3:end])
+    except (ValueError, yaml.YAMLError):
+        return None
+    if not bd or "id" not in bd or "planet_class" not in bd:
+        return None
+    return bd
+
+
+# ---------------------------------------------------------------------------
+# DB queries
+# ---------------------------------------------------------------------------
+
+def query_inhabited_bodies(conn: sqlite3.Connection) -> list[dict]:
+    """Query systems.db for all inhabited bodies with terrain_reference set."""
+    rows = conn.execute("""
+        SELECT
+            b.body_id,
+            b.system_id,
+            b.terrain_reference,
+            b.population,
+            b.settlement_pattern,
+            b.planet_class,
+            b.economic_role,
+            COALESCE(b.cultural_corridor, s.cultural_corridor) AS cultural_corridor
+        FROM bodies b
+        JOIN star_systems s ON b.system_id = s.system_id
+        WHERE b.inhabited = 1
+          AND b.terrain_reference IS NOT NULL
+          AND b.population > 0
+        ORDER BY b.system_id, b.body_id
+    """).fetchall()
+
+    return [
+        {
+            "body_id": row[0],
+            "system_id": row[1],
+            "terrain_reference": row[2],
+            "population": row[3] or 0,
+            "settlement_pattern": row[4],
+            "planet_class": row[5],
+            "economic_role": row[6],
+            "cultural_corridor": row[7],
+        }
+        for row in rows
+    ]
diff --git a/tooling/planet-gen/import_heightmaps.py b/tooling/planet-gen/import_heightmaps.py
index 4b3f53e9b..a6829b1a8 100644
--- a/tooling/planet-gen/import_heightmaps.py
+++ b/tooling/planet-gen/import_heightmaps.py
@@ -41,7 +41,7 @@ if _venv_python.exists() and Path(sys.executable).resolve() != _venv_python.reso
 import numpy as np
 import sqlite3
 
-from generate_atlas import (
+from atlas_common import (
     GRID_W,
     GRID_H,
     DB_PATH,
diff --git a/tooling/planet-gen/import_province_boundaries.py b/tooling/planet-gen/import_province_boundaries.py
index 3da0f25f6..1dd1dfe39 100644
--- a/tooling/planet-gen/import_province_boundaries.py
+++ b/tooling/planet-gen/import_province_boundaries.py
@@ -59,7 +59,7 @@ if _venv_python.exists() and Path(sys.executable).resolve() != _venv_python.reso
 import numpy as np
 import sqlite3
 
-from generate_atlas import (
+from atlas_common import (
     DB_PATH,
     ensure_atlas_schema,
     query_inhabited_bodies,