scripts(refactor[mcp_swap]): rename state dir to libtmux-mcp-dev under XDG_STATE_HOME

Old path ~/.local/state/libtmux-mcp/mcp_swap.json shared its directory
name with the runtime package even though this is dev-only tooling.
New path resolves $XDG_STATE_HOME (defaulting to ~/.local/state) and
namespaces under libtmux-mcp-dev/swap/state.json. State (vs.
cache/config/data) is the correct XDG bucket: the file is
machine-written, must persist across runs so revert can find the right
backup, but is neither safely deletable like cache nor user-edited
like config.

No migration shim: pre-alpha, dev-only, single-user surface. Anyone
holding state from the old path should run revert before pulling, or
manually move ~/.local/state/libtmux-mcp/mcp_swap.json to
~/.local/state/libtmux-mcp-dev/swap/state.json.

Author: tony

scripts/README.md

@@ -50,9 +50,10 @@ invocation with no reinstall step.
 
 - Every rewrite writes a timestamped backup (`<config>.bak.mcp-swap-<ts>`)
   before touching the file.
-- State is tracked in `~/.local/state/libtmux-mcp/mcp_swap.json` so
-  `revert` knows which backup to restore per CLI, including the "added"
-  case where Codex had no libtmux block before.
+- State is tracked in `~/.local/state/libtmux-mcp-dev/swap/state.json`
+  (honours `XDG_STATE_HOME`) so `revert` knows which backup to restore
+  per CLI, including the "added" case where Codex had no libtmux block
+  before.
 - Writes are atomic (tempfile + `os.replace`) and re-validated by
   re-parsing; a bad write is rolled back immediately.
 - `--dry-run` prints a unified diff and writes nothing.

scripts/mcp_swap.py

@@ -70,8 +70,26 @@
 CLIName = t.Literal["claude", "codex", "cursor", "gemini"]
 ALL_CLIS: tuple[CLIName, ...] = ("claude", "codex", "cursor", "gemini")
 
-STATE_DIR = pathlib.Path.home() / ".local" / "state" / "libtmux-mcp"
-STATE_FILE = STATE_DIR / "mcp_swap.json"
+
+def _xdg_state_home() -> pathlib.Path:
+    """Resolve ``$XDG_STATE_HOME`` per the XDG Base Directory spec.
+
+    Defaults to ``~/.local/state`` when the env var is unset or empty.
+    State is the right XDG bucket here (vs. cache / config / data): the
+    file is machine-written, must persist across runs so ``revert`` can
+    locate the right backup, but is not safely deletable like cache nor
+    user-edited like config.
+    """
+    env = os.environ.get("XDG_STATE_HOME")
+    if env:
+        return pathlib.Path(env)
+    return pathlib.Path.home() / ".local" / "state"
+
+
+# ``-dev`` suffix in the namespace makes it loud that this is dev-only
+# tooling state, distinct from the runtime ``libtmux-mcp`` package.
+STATE_DIR = _xdg_state_home() / "libtmux-mcp-dev" / "swap"
+STATE_FILE = STATE_DIR / "state.json"
 STATE_VERSION = 1
 
 BACKUP_SUFFIX_PREFIX = ".bak.mcp-swap-"

tests/test_mcp_swap.py

@@ -66,7 +66,7 @@ def fake_home(tmp_path: pathlib.Path, monkeypatch: pytest.MonkeyPatch) -> pathli
     )
     state_dir = tmp_path / "state"
     monkeypatch.setattr(mcp_swap, "STATE_DIR", state_dir)
-    monkeypatch.setattr(mcp_swap, "STATE_FILE", state_dir / "mcp_swap.json")
+    monkeypatch.setattr(mcp_swap, "STATE_FILE", state_dir / "state.json")
     return tmp_path