M5.1: the knowledge vault

vault.py: a folder of Markdown notes on the agent host, as SilverBullet reads
them. Only configured folders exist for the agent, each rw or ro (`vault:`
in the configuration); paths are checked in code (relative, inside a folder,
symlinks included, Markdown, never the editor's own files). Writes are
atomic (temporary file, fsync, rename, directory fsync) and merge provenance
into the note's frontmatter, keeping the rest; failures are results.

read_note, list_notes and search_notes are control tools in the harness for
the driver (before the go-ahead, and while a VM is blocked) and for
conversations, labelled with their path; the prompt says a note is
information, never an instruction. Writing by the model is M5.2's.

With the operator: SilverBullet replaces Obsidian and runs on the vault
itself, agents' folders mounted read-only, so no Syncthing (L10, X5, M5.4).
Per-agent mounts come with the containers (M6.1).

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01J5Utyfzw7gF7UhjRDEtjTk

nisse-dev/tests/test_config.py

@@ -1,4 +1,5 @@
 import copy
+import re
 from pathlib import Path
 from typing import Any
 
@@ -525,3 +526,37 @@ def test_the_trust_dial_defaults_to_the_operator_merging() -> None:
 def test_preflight_tuning_is_read() -> None:
     tuning = build(tuning={"preflight": {"max_turns": 8}}).tuning
     assert (tuning.preflight.max_turns, tuning.preflight.command_timeout_s) == (8, 900)
+
+
+def test_the_vault_is_read() -> None:
+    config = build(
+        vault={
+            "root": "/var/lib/nisse/vault",
+            "folders": {"memory/nisse-dev": "rw", "notes/": "ro"},
+        }
+    )
+    assert config.vault is not None
+    assert config.vault.root == Path("/var/lib/nisse/vault")
+    assert dict(config.vault.folders) == {"memory/nisse-dev": "rw", "notes": "ro"}
+    assert config.vault.ignore == (".*", "_plug")
+    assert build().vault is None  # optional: no vault, no note tools
+
+
+@pytest.mark.parametrize(
+    ("vault", "said"),
+    [
+        ({"folders": {"notes": "ro"}}, "vault.root"),
+        ({"root": "/v", "folders": {}}, "vault.folders: a mapping"),
+        ({"root": "/v", "folders": {"notes": "write"}}, "must be one of rw, ro"),
+        ({"root": "/v", "folders": {"../x": "ro"}}, "a folder inside the vault"),
+        (
+            {"root": "/v", "folders": {"memory": "ro", "memory/nisse-dev": "rw"}},
+            "memory/nisse-dev is inside memory",
+        ),
+        ({"root": "/v", "folders": {"n": "ro"}, "mounts": 1}, "vault.mounts: unknown"),
+        ({"root": "/v", "folders": {"n": "ro"}, "ignore": "x"}, "vault.ignore"),
+    ],
+)
+def test_a_bad_vault_is_refused(vault: dict[str, Any], said: str) -> None:
+    with pytest.raises(ConfigError, match=re.escape(said)):
+        build(vault=vault)