fix(mcp): handle non-object checkpoint acknowledgements

CHANGELOG.md

@@ -10,6 +10,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 
 ### Bug Fixes
 
+- **`mempalace_memories_filed_away` no longer errors after consuming a valid non-object checkpoint.** The acknowledgement tool deleted `last_checkpoint` and then unconditionally called `.get()` on the decoded JSON, so `null`, arrays, strings, numbers, and booleans produced an internal MCP error with no marker left to retry. It now requires the decoded value to be an object; rejected roots follow the existing generic malformed-checkpoint response without echoing their contents, while valid objects and missing files keep their current behavior. (#2272)
 - **`sweep` books a failed `stat` as a failure again.** The non-regular-file gate added in 3.7.1 reads `stat.S_ISREG(f.stat().st_mode)` inside a `try`, and its `except OSError` printed `SKIP` and moved on. A dangling symlink, a symlink loop and a file unlinked between `rglob` and the gate all raise there, and before the gate existed every one of them reached `sweep()` and was booked in `failures` — so `sweep` went from reporting a transcript it could not read to reporting success. A failed probe is now an error, not a benign file type: it is logged, printed as `WARNING`, and appended to `failures`, while a probe that succeeds and says "not regular" still skips silently. (#2221)
 - **`mempalace init` no longer tracebacks on a directory it cannot enter.** `_parse_gradle`'s `is_file()` gate sat in front of the `try` that the parser's own `except OSError` provides, so a manifest under a directory with `r` but no `x` raised `PermissionError` out of a call that used to answer "no manifest name". The gate moved inside that `try`, and `_collect_manifest_names` stats through `os.path.isfile`, which reports rather than raises. (#2221)
 - **`split` no longer blocks on a FIFO at its own output name, nor writes through a broken link.** The type gate in `main` covers the files the glob listed; `split_file` builds its output names itself, so a pre-existing named pipe at one of them wedged `write_text` in the kernel waiting for a reader. The check asks about the link itself rather than its target, because a dangling symlink at an output name reads as "nothing there" and `write_text` would create the target — landing a chunk outside the output directory. Output names that are anything but a regular file are now skipped with a `SKIP` line. (#2221)

mempalace/mcp_server.py

@@ -4182,9 +4182,17 @@ def tool_memories_filed_away():
             "count": 0,
             "timestamp": None,
         }
+    error_result = {
+        "status": "error",
+        "message": "\u2726 Journal entry filed in the palace",
+        "count": 0,
+        "timestamp": None,
+    }
     try:
         data = json.loads(ack_file.read_text(encoding="utf-8"))
         ack_file.unlink(missing_ok=True)
+        if not isinstance(data, dict):
+            return error_result
         msgs = data.get("msgs", 0)
         return {
             "status": "ok",
@@ -4194,12 +4202,7 @@ def tool_memories_filed_away():
         }
     except (json.JSONDecodeError, OSError):
         ack_file.unlink(missing_ok=True)
-        return {
-            "status": "error",
-            "message": "\u2726 Journal entry filed in the palace",
-            "count": 0,
-            "timestamp": None,
-        }
+        return error_result
 
 
 # ==================== SETTINGS TOOLS ====================

tests/test_mcp_server.py

@@ -4058,6 +4058,72 @@ def test_diary_write_chunk_index_metadata(self, monkeypatch, config, palace_path
         )
 
 
+# ── Silent checkpoint acknowledgement ─────────────────────────────────
+
+
+def _checkpoint_ack_file(tmp_path, monkeypatch):
+    """Point the checkpoint tool at an isolated cross-platform home."""
+    home = tmp_path / "home"
+    state_dir = home / ".mempalace" / "hook_state"
+    state_dir.mkdir(parents=True)
+    monkeypatch.setenv("HOME", str(home))
+    monkeypatch.setenv("USERPROFILE", str(home))
+    drive, tail = os.path.splitdrive(str(home))
+    monkeypatch.setenv("HOMEDRIVE", drive or "C:")
+    monkeypatch.setenv("HOMEPATH", tail or str(home))
+    return state_dir / "last_checkpoint"
+
+
+@pytest.mark.parametrize(
+    "payload",
+    [None, [], "sensitive checkpoint text", 42, True],
+    ids=["null", "array", "string", "number", "boolean"],
+)
+def test_memories_filed_away_consumes_non_object_json(tmp_path, monkeypatch, payload):
+    """Valid JSON roots that are not objects are malformed checkpoints."""
+    from mempalace import mcp_server
+
+    ack_file = _checkpoint_ack_file(tmp_path, monkeypatch)
+    ack_file.write_text(json.dumps(payload), encoding="utf-8")
+
+    result = mcp_server.tool_memories_filed_away()
+
+    assert result == {
+        "status": "error",
+        "message": "\u2726 Journal entry filed in the palace",
+        "count": 0,
+        "timestamp": None,
+    }
+    assert not ack_file.exists()
+    assert "sensitive checkpoint text" not in json.dumps(result)
+
+
+def test_memories_filed_away_preserves_existing_outcomes(tmp_path, monkeypatch):
+    """Valid, invalid-syntax, and missing checkpoints retain their contract."""
+    from mempalace import mcp_server
+
+    ack_file = _checkpoint_ack_file(tmp_path, monkeypatch)
+    ack_file.write_text(json.dumps({"msgs": 7, "ts": "2026-01-01T00:00:00"}), encoding="utf-8")
+    assert mcp_server.tool_memories_filed_away() == {
+        "status": "ok",
+        "message": "\u2726 7 messages tucked into drawers",
+        "count": 7,
+        "timestamp": "2026-01-01T00:00:00",
+    }
+    assert not ack_file.exists()
+
+    ack_file.write_text("{not-json", encoding="utf-8")
+    assert mcp_server.tool_memories_filed_away()["status"] == "error"
+    assert not ack_file.exists()
+
+    assert mcp_server.tool_memories_filed_away() == {
+        "status": "quiet",
+        "message": "No recent journal entry",
+        "count": 0,
+        "timestamp": None,
+    }
+
+
 # ── Cache Invalidation (inode/mtime) ──────────────────────────────────