Install the MCP server with QElectroTech

The MCP server (misc/qet-mcp) was only reachable from a source checkout.
It now ships with every package, next to the program, and finds that
QElectroTech and its element collection from where it sits:

- make install (Linux distributions, snap, flatpak):
  <prefix>/share/qelectrotech/mcp/qet_mcp.py, executable, with its README.
- Windows installer: a new "AI assistant (MCP)" component (on by default,
  ~200 KB), installed to <folder>\mcp. The workflow stages files/mcp, so
  the portable folder and the MSI, which packs all of files/, carry it too.

The server learns the Windows layout (<root>/mcp beside <root>/bin, whose
program is QElectroTech.exe, and <root>/elements), in addition to
<prefix>/share/qelectrotech/mcp. A copy saved anywhere else, even beside
some bin/ folder, is not taken for an installation.

The installer strings are given in all 29 installer languages: French
translated, the others in English until translated, which is what NSIS
would fall back to anyway but without its warning 6040 per language.

Checked: make install into a scratch prefix, then from the installed
script with nothing configured and no qelectrotech on PATH, an SVG export
and a qet_edit placing a common:// element both succeeded. makensis 3.10
compiles the installer with 0 warnings before and after (removing the
French description gives warning 6040), and the installer contains
mcp/qet_mcp.py. Suite 274/274 none skipped; each layout check was
removed in turn and a test failed. Snap/flatpak: installed by the same
CMake rule; launching their QElectroTech from outside is untested.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

misc/qet-mcp/README.md

@@ -82,6 +82,28 @@ Register it with an MCP client, for example:
 QElectroTech (as `<prefix>/share/qelectrotech/mcp/qet_mcp.py`, which also
 finds the installed element collection).
 
+## Installed with QElectroTech
+
+QElectroTech's packages install the server next to the program, and from
+there it finds that QElectroTech and its element collection by itself:
+
+| Package | Server | Finds |
+|---|---|---|
+| `make install`, Linux distributions | `<prefix>/share/qelectrotech/mcp/qet_mcp.py` | `<prefix>/bin/qelectrotech`, `<prefix>/share/qelectrotech/elements` |
+| Windows installer, MSI, portable folder | `<folder>\mcp\qet_mcp.py` (the "AI assistant (MCP)" component) | `<folder>\bin\QElectroTech.exe`, `<folder>\elements` |
+
+So a client configuration needs only the path to the server and the
+workspace, for example on Windows:
+
+```json
+"args": ["C:\\Program Files\\QElectroTech\\mcp\\qet_mcp.py"]
+```
+
+Snap and flatpak install it too. Their QElectroTech is built to run inside
+the package's sandbox, and starting it from the server has not been tested:
+the tools that read a file work, exports and edits may not. If they fail,
+point `QET_BINARY` at a QElectroTech installed another way.
+
 ## Using it from the Claude app
 
 A web chat in a browser cannot start a program on your computer, so it

misc/qet-mcp/qet_mcp.py

@@ -3189,12 +3189,24 @@ def _env_paths(name: str) -> list:
     return out
 
 
-def _installed_prefix() -> Path | None:
-    """The install prefix when this script is <prefix>/share/qelectrotech/mcp/."""
+def _installation() -> tuple | None:
+    """(program directory, element collection) of the QElectroTech this
+    script was installed with, or None when it runs from anywhere else.
+
+    Two layouts, both put there by QElectroTech's own packaging:
+      <prefix>/share/qelectrotech/mcp/  -> <prefix>/bin, <prefix>/share/qelectrotech/elements
+                                           (make install: Linux, snap, flatpak, macOS)
+      <root>/mcp/                       -> <root>/bin, <root>/elements
+                                           (the Windows installers and portable folder)
+    """
     here = Path(__file__).resolve().parent
-    if here.name == "mcp" and here.parent.name == "qelectrotech" \
-            and here.parent.parent.name == "share":
-        return here.parent.parent.parent
+    if here.name != "mcp":
+        return None
+    if here.parent.name == "qelectrotech" and here.parent.parent.name == "share":
+        prefix = here.parent.parent.parent
+        return prefix / "bin", here.parent / "elements"
+    if (here.parent / "bin").is_dir():
+        return here.parent / "bin", here.parent / "elements"
     return None
 
 
@@ -3208,10 +3220,12 @@ def resolve_binary() -> Path | None:
     env = os.environ.get("QET_BINARY", "").strip()
     if env:
         return Path(env).expanduser().resolve()
-    prefix = _installed_prefix()
-    if prefix is not None:
-        for name in ("qelectrotech", "qelectrotech.exe"):
-            cand = prefix / "bin" / name
+    install = _installation()
+    if install is not None:
+        # The Windows build names it QElectroTech.exe; only a case-sensitive
+        # file system tells the spellings apart.
+        for name in ("qelectrotech", "qelectrotech.exe", "QElectroTech.exe"):
+            cand = install[0] / name
             if cand.is_file():
                 return cand.resolve()
     found = shutil.which("qelectrotech")
@@ -3220,11 +3234,9 @@ def resolve_binary() -> Path | None:
 
 def default_elements_dir() -> Path | None:
     """The element collection of the install this script ships in, if any."""
-    prefix = _installed_prefix()
-    if prefix is not None:
-        coll = prefix / "share" / "qelectrotech" / "elements"
-        if coll.is_dir():
-            return coll.resolve()
+    install = _installation()
+    if install is not None and install[1].is_dir():
+        return install[1].resolve()
     return None
 
 

misc/qet-mcp/test_qet_mcp.py

@@ -2021,6 +2021,43 @@ class BinaryPolicy(unittest.TestCase):
         self.assertEqual(args["elements_dir"],
                          str((prefix / "share" / "qelectrotech" / "elements").resolve()))
 
+    def installed_at(self, root: Path, mcp: Path):
+        """Import a copy of the server placed at mcp/qet_mcp.py."""
+        import importlib.util
+        mcp.mkdir(parents=True)
+        shutil.copy2(HERE / "qet_mcp.py", mcp / "qet_mcp.py")
+        spec = importlib.util.spec_from_file_location(f"qet_mcp_{root.name}", mcp / "qet_mcp.py")
+        inst = importlib.util.module_from_spec(spec)
+        spec.loader.exec_module(inst)
+        return inst
+
+    def test_the_windows_layout_is_found_too(self):
+        """The Windows installers and the portable folder put the server in
+        <root>/mcp, the program in <root>/bin as QElectroTech.exe, and the
+        collection in <root>/elements."""
+        root = Path(self.tmp.name) / "QElectroTech"
+        (root / "elements").mkdir(parents=True)
+        exe = fake_qet(root / "bin", "QElectroTech.exe")
+        inst = self.installed_at(root, root / "mcp")
+        del os.environ["QET_BINARY"]
+        args = {"project": str(self.root / "ok.qet")}
+        inst.enforce_path_policy("qet_query", args)
+        self.assertEqual(args["binary"], str(exe.resolve()))
+        self.assertEqual(args["elements_dir"], str((root / "elements").resolve()))
+
+    def test_a_copy_saved_anywhere_is_not_an_install(self):
+        """A downloaded copy sitting beside some bin/ folder must not go
+        looking for QElectroTech there."""
+        home = Path(self.tmp.name) / "home"
+        fake_qet(home / "bin")
+        inst = self.installed_at(home, home / "Downloads")
+        self.assertIsNone(inst._installation())
+
+    def test_a_folder_named_mcp_is_not_an_install(self):
+        """Without a bin/ beside it, an mcp/ folder is just a folder."""
+        inst = self.installed_at(Path(self.tmp.name) / "x", Path(self.tmp.name) / "x" / "mcp")
+        self.assertIsNone(inst._installation())
+
 
 class ScriptingDisabledHint(unittest.TestCase):
     """QElectroTech may refuse to run scripts at all, and says so in French.