feat: brain/index.go shebang; mail import is not a brain write (D14).

Commands live at bin/brain/{index,get,stats,eval,watch}.go and
bin/mail/import.go, bin/markdown/import.go, bin/postgres/query.go.
Python remains the Ladybug write worker. index_mail is a deprecation
shim that rebuilds via --with-mail.

bin/tools/kblib.py

@@ -135,7 +135,7 @@ def create_fts_and_vector(conn: ladybug.Connection, force: bool = False) -> None
 
     `force=True` is accepted for API compatibility but does **not** drop.
     Fresh indexes require deleting `var/kb.lbug` and rebuilding
-    (`bin/kb/index --rebuild`).
+    (`bin/brain/index.go --rebuild`).
     """
     del force  # API compat; DROP is unsafe — see docstring
     names = leaf_index_names(conn)
@@ -145,7 +145,7 @@ def create_fts_and_vector(conn: ladybug.Connection, force: bool = False) -> None
         except Exception as e:
             raise RuntimeError(
                 "CREATE_FTS_INDEX failed (often ghost catalog after DROP INDEX). "
-                "Delete var/kb.lbug and run bin/kb/index --rebuild. "
+                "Delete var/kb.lbug and run bin/brain/index.go --rebuild. "
                 f"Cause: {e}"
             ) from e
     if "Leaf_vec" not in names:
@@ -158,7 +158,7 @@ def create_fts_and_vector(conn: ladybug.Connection, force: bool = False) -> None
             raise RuntimeError(
                 "CREATE_VECTOR_INDEX failed (often ghost catalog after DROP INDEX "
                 "Leaf.Leaf_vec → `_0_Leaf_vec_UPPER already exists in catalog`). "
-                "Delete var/kb.lbug and run bin/kb/index --rebuild. "
+                "Delete var/kb.lbug and run bin/brain/index.go --rebuild. "
                 f"Cause: {e}"
             ) from e
     names = leaf_index_names(conn)
@@ -237,6 +237,6 @@ def stats(conn: ladybug.Connection) -> dict:
 
 def open_readonly() -> tuple[ladybug.Database, ladybug.Connection]:
     if not DB_PATH.exists():
-        raise FileNotFoundError(f"{DB_PATH} missing - run bin/kb/index first")
+        raise FileNotFoundError(f"{DB_PATH} missing - run bin/brain/index.go --rebuild first")
     db, conn = connect(read_only=True)
     return db, conn

bin/tools/mailleafs.py

@@ -0,0 +1,37 @@
+"""Mail markdown under var/mail → info leafs. Conversion stays off the brain DB."""
+from __future__ import annotations
+
+import json
+from pathlib import Path
+
+from mdleaves import read_markdown, to_all
+
+
+def msg_date(md: Path) -> str:
+    j = md.parent / "message.json"
+    try:
+        d = json.loads(j.read_text(encoding="utf-8"))
+        return (d.get("receivedDate") or d.get("receivedAt") or "")[:10]
+    except (OSError, json.JSONDecodeError, TypeError):
+        return ""
+
+
+def from_mail_root(root: Path, limit: int = 0, since: str = "", repo: str = "ooMail") -> list[dict]:
+    if not root.is_dir():
+        return []
+    mds = sorted(root.rglob("message.md"))
+    if since:
+        mds = [m for m in mds if msg_date(m) >= since]
+    if limit:
+        mds = mds[:limit]
+    leafs: list[dict] = []
+    for md in mds:
+        files = [md] + sorted((md.parent / "attachments").glob("*.md"))
+        for f in files:
+            if not f.exists():
+                continue
+            for lf in to_all(read_markdown(f), f, repo=repo):
+                lf["source"] = f"ooMail:{md.parent.name}:{f.name}"
+                lf["how"] = "mail/import"
+                leafs.append(lf)
+    return leafs

bin/tools/test_bin_layout.py

@@ -63,3 +63,31 @@ class BinLayoutTest(unittest.TestCase):
             (ROOT / "bin" / "chats" / "linkedin.go").exists(),
             "parser must not stay under bin/chats as a second main",
         )
+
+    def _assert_shebang(self, rel: str) -> None:
+        p = ROOT / rel
+        self.assertTrue(p.is_file(), f"missing {rel}")
+        first = p.read_text().splitlines()[0]
+        self.assertTrue(
+            first.startswith("//usr/bin/env go run"),
+            f"{rel} shebang, got {first!r}",
+        )
+
+    def test_brain_methods_are_shebangs(self) -> None:
+        for method in ("index.go", "get.go", "stats.go", "eval.go", "watch.go"):
+            self._assert_shebang(f"bin/brain/{method}")
+
+    def test_mail_import_is_shebang_not_brain_write(self) -> None:
+        self._assert_shebang("bin/mail/import.go")
+        index_mail = (ROOT / "bin" / "mail" / "index_mail").read_text()
+        self.assertIn(
+            "bin/brain/index.go",
+            index_mail,
+            "index_mail must point at bin/brain/index.go",
+        )
+
+    def test_markdown_import_is_shebang(self) -> None:
+        self._assert_shebang("bin/markdown/import.go")
+
+    def test_postgres_query_is_shebang(self) -> None:
+        self._assert_shebang("bin/postgres/query.go")

bin/tools/test_mailleafs.py

@@ -0,0 +1,46 @@
+"""Mail markdown → leafs (no Ladybug). Brain index --with-mail uses this."""
+from __future__ import annotations
+
+import json
+import sys
+import tempfile
+import unittest
+from pathlib import Path
+
+sys.path.insert(0, str(Path(__file__).resolve().parent))
+
+import mailleafs  # noqa: E402
+
+
+class MailLeafsTest(unittest.TestCase):
+    def test_message_md_becomes_info_leaf(self) -> None:
+        root = Path(tempfile.mkdtemp())
+        msg = root / "inbox" / "alice-1"
+        msg.mkdir(parents=True)
+        (msg / "message.json").write_text(
+            json.dumps({"receivedDate": "2026-01-15T10:00:00Z", "subject": "Hello"}),
+            encoding="utf-8",
+        )
+        (msg / "message.md").write_text(
+            "---\nroot: info\n---\n\n# Hello\n\nFrom Alice to Bob.\n",
+            encoding="utf-8",
+        )
+        leafs = mailleafs.from_mail_root(root)
+        self.assertEqual(len(leafs), 1)
+        self.assertIn("Alice", leafs[0]["text"])
+        self.assertTrue(leafs[0]["source"].startswith("ooMail:"))
+        self.assertEqual(leafs[0]["how"], "mail/import")
+
+    def test_since_filters_by_message_json_date(self) -> None:
+        root = Path(tempfile.mkdtemp())
+        for name, day in (("old", "2025-01-01"), ("new", "2026-06-01")):
+            d = root / "inbox" / name
+            d.mkdir(parents=True)
+            (d / "message.json").write_text(
+                json.dumps({"receivedDate": f"{day}T00:00:00Z"}),
+                encoding="utf-8",
+            )
+            (d / "message.md").write_text(f"# {name}\n\nbody\n", encoding="utf-8")
+        leafs = mailleafs.from_mail_root(root, since="2026-01-01")
+        self.assertEqual(len(leafs), 1)
+        self.assertIn("new", leafs[0]["text"])

bin/tools/test_published_docs.py

@@ -30,6 +30,15 @@ class PublishedDocsTest(unittest.TestCase):
             "README deduction search must name bin/brain/search.go",
         )
 
+    def test_readme_index_is_brain_not_index_mail(self) -> None:
+        text = (ROOT / "README.md").read_text()
+        self.assertIn("bin/brain/index.go", text)
+        self.assertNotIn(
+            "bin/mail/index_mail",
+            text,
+            "mail index is a brain write; README must name bin/brain/index.go",
+        )
+
     def test_docs_do_not_claim_hop_walks(self) -> None:
         paths = [
             ROOT / "README.md",