🚧 WIP

.gitignore

@@ -13,4 +13,7 @@ dist/
 
 # Local runtime artifacts (copy config.example.yaml -> config.yaml)
 config.yaml
-logs/
+logs/
+
+# Generated by scripts/build_exe.ps1 at build time
+scripts/.exe_version_info.txt

.vscode/launch.json

@@ -25,6 +25,21 @@
                 "PYTHONUNBUFFERED": "1"
             }
         },
+        {
+            // One-shot read of every configured tag — the pre-deployment check.
+            "name": "opcda-diagnozer: probe",
+            "type": "debugpy",
+            "request": "launch",
+            "python": "${workspaceFolder}/.venv/Scripts/python.exe",
+            "module": "opcda_diagnozer",
+            "args": ["probe", "--config", "config.example.yaml"],
+            "cwd": "${workspaceFolder}",
+            "console": "integratedTerminal",
+            "justMyCode": false,
+            "env": {
+                "PYTHONUNBUFFERED": "1"
+            }
+        },
         {
             // Basic use: validate the example config without connecting.
             "name": "opcda-diagnozer: check-config",
@@ -127,6 +142,28 @@
             "env": {
                 "PYTHONUNBUFFERED": "1"
             }
+        },
+        {
+            // One-shot read of tags with a --server override — no config
+            // file needed. Adjust the tags (and optionally the ProgID) to
+            // whichever server is registered on your machine.
+            "name": "opcda-diagnozer: read (--server override)",
+            "type": "debugpy",
+            "request": "launch",
+            "python": "${workspaceFolder}/.venv/Scripts/python.exe",
+            "module": "opcda_diagnozer",
+            "args": [
+                "read",
+                "--server", "Matrikon.OPC.Simulation.1",
+                "Bucket Brigade.Int1",
+                "Bucket Brigade.Real8"
+            ],
+            "cwd": "${workspaceFolder}",
+            "console": "integratedTerminal",
+            "justMyCode": false,
+            "env": {
+                "PYTHONUNBUFFERED": "1"
+            }
         }
     ],
     "inputs": [

README.md

@@ -62,6 +62,12 @@ opcda-diagnozer list-tags "Simulation Items" "Bucket Brigade"   # equivalent
 opcda-diagnozer list-tags --recursive "Simulation Items"  # whole subtree
 opcda-diagnozer list-tags                                 # every tag on the server
 
+# read tags right now (validation tool) — no config needed with --server
+opcda-diagnozer read --server Matrikon.OPC.Simulation.1 "Bucket Brigade.Int1"
+opcda-diagnozer read --json "Bucket Brigade.Int1" "Bucket Brigade.Real8"
+opcda-diagnozer read                                     # the config's tags
+opcda-diagnozer read --source cache "Bucket Brigade.Int1" # server cache, no device trip
+
 # validate config
 opcda-diagnozer check-config
 
@@ -89,6 +95,17 @@ device path is either one dotted string (`"Simulation Items.Bucket Brigade"`) or
 several quoted branch names — use the latter when a branch name itself contains a
 dot. On flat-namespace servers (`organization: flat`) every tag hangs directly off
 the root; `list-tags` without a device lists them all.
+
+Every connecting verb (`read`, `probe`, `list-devices`, `list-tags`) accepts
+`--server PROGID` and `--host HOST` to **override the config's `opc` section** —
+point a one-shot check at any server without touching the deployed config.yaml.
+With `--server` given, no config file is needed at all; without it, the config must
+exist (and `probe`/`read` read the config's tag list unless tags are passed).
+
+`read` prints one row per tag with the decoded quality and the device timestamp;
+a non-GOOD or failing tag makes the exit code non-zero, so it doubles as a
+scriptable health check. `--source cache` reads the server cache instead of
+forcing a device round-trip.
 ### Configuration example (`config.example.yaml`)
 
 ```yaml
@@ -188,6 +205,47 @@ Notes:
   (`py install 3.14 -a x86`) or the installer from python.org ("Download Windows
   installer (32-bit)").
 
+## Building the Windows executable
+
+`scripts/build_exe.ps1` packages the CLI as a standalone **32-bit** console exe
+with [PyInstaller](https://pyinstaller.org) — no Python installation needed on
+the target host:
+
+```powershell
+& ".\.venv\Scripts\python.exe" -m pip install pyinstaller   # once
+.\scripts\build_exe.ps1                                     # dist\opcda-diagnozer\
+.\scripts\build_exe.ps1 -Onefile                            # single exe alternative
+.\scripts\build_exe.ps1 -Clean                              # fresh rebuild
+```
+
+The script refuses to run from a 64-bit interpreter (the exe must load the
+32-bit OPC DA wrapper DLLs, SPECIFICATION §11), re-verifies the produced PE
+really is 32-bit, embeds the project version in the exe properties, declares
+the hidden imports the code loads lazily (pywin32 COM, browse modules, the
+Phase 3 service host), and smoke-tests the artifact (`--version`,
+`check-config`, `list-servers --source registry`) after building. It also
+installs PyInstaller into the venv automatically if it is missing.
+
+If your policy blocks the script, run it with
+`powershell -NoProfile -ExecutionPolicy Bypass -File scripts\build_exe.ps1`.
+
+Deployment notes:
+- The **default config path** of a frozen exe is `config.yaml` **next to the
+  exe** — not the working directory. A Windows service starts with
+  `CWD = C:\Windows\System32`, so the relative default would silently point
+  there; the exe-dir default keeps the deployment layout simple
+  (`C:\Program Files\OPCDA-Diagnozer\{opcda-diagnozer.exe, config.yaml}`).
+- The exe is a console application that hosts every CLI verb, including the
+  future `run` / `probe` / service verbs. The Phase 3 Windows service
+  (`install` verb) will point `sc.exe` at this same exe with the service-host
+  entry point.
+- The Automation Wrapper DLL (`OPCAutomation.dll`) is **not** bundled — it is
+  a machine-installed COM component (registered in the registry), exactly like
+  the OPC DA servers the tool connects to. Only Python code and its
+  dependencies are frozen.
+- `onedir` is the default (faster startup, AV-friendlier); `--onefile` trades
+  startup time for a single file. `--clean` removes `build/` + `dist/` first.
+
 ## Documentation
 
 - [Specification](docs/SPECIFICATION.md) — detection rules, event model, operational behavior, acceptance criteria

src/opcda_diagnozer/main.py

@@ -12,6 +12,7 @@ from __future__ import annotations
 import argparse
 import sys
 from collections.abc import Sequence
+from pathlib import Path
 
 from opcda_diagnozer import __version__
 from opcda_diagnozer.config import ConfigError, load_config
@@ -20,9 +21,21 @@ from opcda_diagnozer.opc.discovery import ServerInfo, list_servers
 
 DEFAULT_CONFIG = "config.yaml"
 
+
+def _default_config_path() -> str:
+    """Where the config lives by default: CWD in source runs, exe dir when frozen.
+
+    A frozen exe must not rely on the CWD: a Windows service starts with
+    ``CWD = C:\\Windows\\System32``, so the relative name would silently resolve
+    into System32. Frozen runs therefore default to ``config.yaml`` **next to
+    the exe** — the deployment layout the Phase 3 service will use (SPEC §6.4).
+    """
+    if getattr(sys, "frozen", False):
+        return str(Path(sys.executable).resolve().parent / DEFAULT_CONFIG)
+    return DEFAULT_CONFIG
+
 _NOT_IMPLEMENTED: dict[str, str] = {
     "run": "Phase 1 (core engine)",
-    "probe": "Phase 1 (core engine)",
     "list-items": "superseded by list-devices / list-tags",
     "install": "Phase 3 (Windows service)",
     "uninstall": "Phase 3 (Windows service)",
@@ -34,11 +47,30 @@ _NOT_IMPLEMENTED: dict[str, str] = {
 def _add_config_option(parser: argparse.ArgumentParser) -> None:
     parser.add_argument(
         "--config", "-c",
-        default=DEFAULT_CONFIG,
+        default=_default_config_path(),
         help="path to the YAML config (default: %(default)s)",
     )
 
 
+def _add_server_overrides(parser: argparse.ArgumentParser) -> None:
+    """--server/--host override the config's opc section (SPECIFICATION §6).
+
+    They make one-shot CLI use possible without a config file — and let an
+    ops engineer point a validation verb at a different server without
+    touching the deployed config.yaml.
+    """
+    parser.add_argument(
+        "--server",
+        metavar="PROGID",
+        help="OPC DA server ProgID, overriding the config (e.g. Matrikon.OPC.Simulation.1)",
+    )
+    parser.add_argument(
+        "--host",
+        metavar="HOST",
+        help="remote DCOM host, overriding the config (omit for a local server)",
+    )
+
+
 def _build_parser() -> argparse.ArgumentParser:
     parser = argparse.ArgumentParser(
         prog="opcda-diagnozer",
@@ -53,8 +85,44 @@ def _build_parser() -> argparse.ArgumentParser:
     p = sub.add_parser("run", help="run in the foreground (console)")
     _add_config_option(p)
 
-    p = sub.add_parser("probe", help="connect once and print one read of every configured tag")
+    p = sub.add_parser(
+        "read",
+        help="connect once and read the given tags (a quick validation tool)",
+    )
     _add_config_option(p)
+    _add_server_overrides(p)
+    p.add_argument(
+        "tags",
+        nargs="*",
+        metavar="TAG",
+        help="tag ItemIDs to read (e.g. 'Bucket Brigade.Int1'); omitted -> the "
+        "config's tags",
+    )
+    p.add_argument(
+        "--source",
+        choices=("device", "cache"),
+        default="device",
+        help="read from the device (round-trip to the PLC) or the server cache "
+        "(default: %(default)s)",
+    )
+    p.add_argument(
+        "--json",
+        action="store_true",
+        help="emit one JSON object per tag (for scripts) instead of a table",
+    )
+
+    p = sub.add_parser(
+        "probe",
+        help="connect once and print one read of every configured tag",
+    )
+    _add_config_option(p)
+    _add_server_overrides(p)
+    p.add_argument(
+        "--source",
+        choices=("device", "cache"),
+        default="device",
+        help="read from the device or the server cache (default: %(default)s)",
+    )
 
     p = sub.add_parser("check-config", help="validate the configuration and exit")
     _add_config_option(p)
@@ -90,6 +158,7 @@ def _build_parser() -> argparse.ArgumentParser:
         help="list the devices (address-space branches) exposed by the configured server",
     )
     _add_config_option(p)
+    _add_server_overrides(p)
     p.add_argument(
         "--depth",
         type=int,
@@ -113,6 +182,7 @@ def _build_parser() -> argparse.ArgumentParser:
         help="list the tags (leaves) of one device, or every tag on the server",
     )
     _add_config_option(p)
+    _add_server_overrides(p)
     p.add_argument(
         "device",
         nargs="*",
@@ -211,19 +281,36 @@ def _cmd_list_servers(host: str | None, source: str, as_json: bool) -> int:
     return 0
 
 
-def _connect_from_config(config_path: str):
+def _connect_from_config(config_path: str, server: str | None = None, host: str | None = None):
-    """Load the config and connect to its configured server (Automation Wrapper).
+    """Load the config (when needed) and connect; --server/--host override opc.
+
+    Overrides make one-shot CLI use possible without a config file: when
+    ``--server`` is given, a missing config file is not an error and the
+    remaining settings fall back to their defaults. Without ``--server`` the
+    config must exist (its ``opc`` section decides where to connect).
 
     Returns the connected client; raises :class:`ConfigError` / :class:`OpcError`
     with actionable messages for the caller to print.
     """
     from opcda_diagnozer.opc.automation import AutomationOpcClient
 
-    config = load_config(config_path)
+    connect_timeout_s = 10.0  # OpcConfig default
+    config_exists = Path(config_path).is_file()
+    if config_exists:
+        config = load_config(config_path)
+        server = server or config.opc.server
+        if host is None:
+            host = config.opc.host
+        connect_timeout_s = config.opc.connect_timeout_s
+    elif server is None:
+        raise ConfigError(
+            f"config file not found: {config_path} - pass --server (and optionally "
+            "--host) to connect without a config, or create the config first"
+        )
     client = AutomationOpcClient(
-        server=config.opc.server,
+        server=server,
-        host=config.opc.host,
+        host=host,
-        connect_timeout_s=config.opc.connect_timeout_s,
+        connect_timeout_s=connect_timeout_s,
     )
     client.connect()
     return client
@@ -257,11 +344,14 @@ def _print_devices(space, as_json: bool) -> None:
         print(f"  {device.qualified_name:<{width}}  ({', '.join(notes)})")
 
 
-def _cmd_list_devices(config_path: str, depth: int, include_counts: bool, as_json: bool) -> int:
+def _cmd_list_devices(
+    config_path: str, server: str | None, host: str | None,
+    depth: int, include_counts: bool, as_json: bool,
+) -> int:
     from opcda_diagnozer.opc.browse import list_devices
 
     try:
-        client = _connect_from_config(config_path)
+        client = _connect_from_config(config_path, server, host)
         browser = None
         try:
             browser = client.create_browser()
@@ -317,6 +407,8 @@ def _print_tags(tags, device_path: tuple[str, ...], recursive: bool, as_json: bo
 
 def _cmd_list_tags(
     config_path: str,
+    server: str | None,
+    host: str | None,
     device: Sequence[str],
     recursive: bool,
     as_json: bool,
@@ -327,7 +419,7 @@ def _cmd_list_tags(
     # explicit branch names (names may contain dots then).
     device_arg = device[0] if len(device) == 1 else list(device)
     try:
-        client = _connect_from_config(config_path)
+        client = _connect_from_config(config_path, server, host)
         browser = None
         try:
             browser = client.create_browser()
@@ -353,6 +445,111 @@ def _cmd_list_tags(
     return 0
 
 
+def _print_read_results(results, as_json: bool) -> int:
+    """Human table / JSON-lines output for the read/probe verbs."""
+    from opcda_diagnozer.quality import decode_quality
+
+    failures = 0
+    if as_json:
+        import json
+
+        for result in results:
+            quality = decode_quality(result.quality_raw)
+            payload = {
+                "tag": result.tag,
+                "value": result.value,
+                "quality_raw": result.quality_raw,
+                "quality": quality.name,
+                "quality_class": quality.quality_class.value,
+                "device_time_utc": (
+                    result.device_time.isoformat() if result.device_time else None
+                ),
+                "error": result.error,
+            }
+            if result.error or quality.quality_class.value != "GOOD":
+                failures += 1
+            print(json.dumps(payload, ensure_ascii=False, default=str))
+        return failures
+    if not results:
+        print("no tags to read")
+        return 0
+    width = max(len(r.tag) for r in results)
+    print(f"{'tag':<{width}}  value                          quality  device time (UTC)")
+    for result in results:
+        quality = decode_quality(result.quality_raw)
+        if result.error:
+            failures += 1
+            print(f"  {result.tag:<{width}}  ERROR: {result.error}")
+            continue
+        marker = "" if quality.quality_class.value == "GOOD" else "  <-- " + quality.name
+        if quality.quality_class.value != "GOOD":
+            failures += 1
+        time_str = (
+            result.device_time.strftime("%Y-%m-%d %H:%M:%S.%f")[:-3]
+            if result.device_time
+            else "-"
+        )
+        print(
+            f"  {result.tag:<{width}}  {str(result.value):<30} {quality.raw_hex}   {time_str}{marker}"
+        )
+    return failures
+
+
+def _cmd_read(
+    config_path: str,
+    server: str | None,
+    host: str | None,
+    tags: Sequence[str],
+    source: str,
+    as_json: bool,
+) -> int:
+    """One-shot read of explicit tags (or the config's tags) from the server."""
+    from opcda_diagnozer.opc.base import OPCDataSource
+
+    requested = list(tags)
+    try:
+        # connect first: a missing config with no --server must fail here with
+        # the actionable hint (before the tags load below can complain).
+        client = _connect_from_config(config_path, server, host)
+        if not requested:
+            # no tags given -> use the config's tags (config is mandatory then)
+            config = load_config(config_path)
+            requested = [t.name for t in config.tags]
+    except ConfigError as exc:
+        print(f"read: FAILED\n  {exc}", file=sys.stderr)
+        return 2
+    except OpcError as exc:
+        print(f"read: FAILED\n  {exc}", file=sys.stderr)
+        return 2
+    data_source = OPCDataSource.DEVICE if source == "device" else OPCDataSource.CACHE
+    try:
+        results = client.read(requested, source=data_source)
+    except OpcError as exc:
+        print(f"read: FAILED\n  {exc}", file=sys.stderr)
+        client.close()
+        return 2
+    finally:
+        client.close()
+    failures = _print_read_results(results, as_json)
+    if failures:
+        print(
+            f"read: {failures} of {len(results)} tag(s) did not read GOOD",
+            file=sys.stderr,
+        )
+        return 1
+    return 0
+
+
+def _cmd_probe(
+    config_path: str,
+    server: str | None,
+    host: str | None,
+    source: str,
+) -> int:
+    """Connect once, read every configured tag once, print — the pre-deploy check."""
+    return _cmd_read(config_path, server, host, (), source, as_json=False)
+
+
 def main(argv: Sequence[str] | None = None) -> int:
     """CLI entry point (console script + ``python -m opcda_diagnozer``)."""
     args = _build_parser().parse_args(argv)
@@ -361,9 +558,19 @@ def main(argv: Sequence[str] | None = None) -> int:
     if args.verb == "list-servers":
         return _cmd_list_servers(args.host, args.source, args.json)
     if args.verb == "list-devices":
-        return _cmd_list_devices(args.config, args.depth, not args.no_counts, args.json)
+        return _cmd_list_devices(
+            args.config, args.server, args.host, args.depth, not args.no_counts, args.json
+        )
     if args.verb == "list-tags":
-        return _cmd_list_tags(args.config, args.device, args.recursive, args.json)
+        return _cmd_list_tags(
+            args.config, args.server, args.host, args.device, args.recursive, args.json
+        )
+    if args.verb == "read":
+        return _cmd_read(
+            args.config, args.server, args.host, args.tags, args.source, args.json
+        )
+    if args.verb == "probe":
+        return _cmd_probe(args.config, args.server, args.host, args.source)
     phase = _NOT_IMPLEMENTED[args.verb]
     print(
         f"{args.verb}: not implemented yet — planned for {phase} "

src/opcda_diagnozer/opc/automation.py

@@ -17,23 +17,31 @@ Matrikon.OPC.Simulation.1): ``Connect(progId)`` / ``Connect(progId, node)``,
 ``CurrentPosition``; ``Organization`` 1 = hierarchical, 2 = flat. Bad branch
 names raise ``E_INVALIDARG``; ``MoveTo`` requires a *sequence* (a bare string
 is a pywin32 SAFEARRAY ``TypeError``).
+
+**Reads** (verified live): the wrapper's ``SyncRead`` cannot be marshalled by
+pywin32 (SAFEARRAY ByRef out-params fail in every invocation shape), but
+``OPCItem.Read(Source)`` + the ``Value`` / ``Quality`` / ``TimeStamp``
+properties work — per-item reads with only scalar out-params. Data-source
+constants come from the wrapper typelib: ``OPCCache = 1``, ``OPCDevice = 2``.
+``TimeStamp`` is a tz-aware ``pywintypes.datetime`` (converted with
+``astimezone(timezone.utc)`` for the UTC event model, SPECIFICATION §6).
 """
 
 from __future__ import annotations
 
 from collections.abc import Sequence
+from datetime import datetime, timezone
 from typing import Any
 
 from opcda_diagnozer.opc.base import (
     Browser,
+    OPCDataSource,
     OpcError,
     ReadResult,
     TagInfo,
     as_com_error,
 )
 
-_NOT_IMPL = "Phase 1: Automation Wrapper adapter (docs/IMPLEMENTATION_PLAN.md §4.4)"
-
 #: OPC_BROWSE organization constants (Automation Wrapper): 1 = hierarchical,
 #: 2 = flat (tags addressed by bare ItemID, no branches to walk).
 _ORGANIZATION_LABELS = {1: "hierarchical", 2: "flat"}
@@ -120,9 +128,10 @@ class _AutomationBrowser:
 class AutomationOpcClient:
     """``win32com``-based :class:`OpcClient`.
 
-    ``connect`` / ``create_browser`` / ``close`` are live (they power the
+    ``connect`` / ``create_browser`` / ``read`` / ``close`` are live: they
-    ``list-devices`` / ``list-tags`` validation verbs); ``read`` lands with the
+    power the ``list-devices`` / ``list-tags`` validation verbs and the
-    Phase 1 core engine (IMPLEMENTATION_PLAN §4.4).
+    one-shot ``read`` / ``probe`` CLI verbs. The Phase 1 poller builds on this
+    same adapter (IMPLEMENTATION_PLAN §4.4).
     """
 
     def __init__(self, server: str, host: str | None = None, connect_timeout_s: float = 10.0) -> None:
@@ -214,9 +223,92 @@ class AutomationOpcClient:
             self._com_initialized = False
             pythoncom.CoUninitialize()
 
-    def read(self, tags: Sequence[str]) -> list[ReadResult]:
+    def read(
-        self._require_pywin32()
+        self, tags: Sequence[str], source: OPCDataSource = OPCDataSource.DEVICE
-        raise NotImplementedError(_NOT_IMPL)
+    ) -> list[ReadResult]:
+        """Read the given tags from the connected server.
+
+        Uses one throwaway group with one item per tag and per-item
+        ``Item.Read(Source)`` (see the module docstring: the wrapper's
+        ``SyncRead`` cannot be marshalled by pywin32). A tag the server does
+        not know yields a :class:`ReadResult` with ``error`` set and a
+        ``BAD_CONFIG_ERROR``-style quality of 0 — never an exception, matching
+        the per-tag error contract of :class:`ReadResult` (IMPLEMENTATION_PLAN
+        §4.3). The group (and its items) is removed afterwards so repeated
+        calls never leak groups on the server.
+        """
+        if self._opc is None:
+            raise OpcError("AutomationOpcClient: read() before connect()")
+        results: list[ReadResult] = []
+        group = None
+        items_collection = None
+        live_items: list[tuple[str, Any]] = []  # (tag, item) in request order
+        try:
+            try:
+                group = self._opc.OPCGroups.Add("DiagnozerRead")
+                items_collection = group.OPCItems
+                errors: list[str | None] = [None] * len(tags)
+                for index, tag in enumerate(tags):
+                    try:
+                        item = items_collection.AddItem(tag, index + 1)
+                        live_items.append((tag, item))
+                    except Exception as exc:  # noqa: BLE001 — per-tag error
+                        results.append(
+                            ReadResult(
+                                tag=tag,
+                                value=None,
+                                quality_raw=0,
+                                device_time=None,
+                                error=str(as_com_error(f"cannot add tag {tag!r}", exc)),
+                            )
+                        )
+                for tag, item in live_items:
+                    try:
+                        item.Read(int(source))
+                        raw_ts = item.TimeStamp
+                        # pywintypes.datetime is a datetime subclass; normalize
+                        # to UTC for the event model (SPECIFICATION §6).
+                        device_time = (
+                            raw_ts.astimezone(timezone.utc) if raw_ts is not None else None
+                        )
+                        results.append(
+                            ReadResult(
+                                tag=tag,
+                                value=item.Value,
+                                quality_raw=int(item.Quality),
+                                device_time=device_time,
+                            )
+                        )
+                    except Exception as exc:  # noqa: BLE001 — per-tag error
+                        results.append(
+                            ReadResult(
+                                tag=tag,
+                                value=None,
+                                quality_raw=0,
+                                device_time=None,
+                                error=str(as_com_error(f"read of tag {tag!r} failed", exc)),
+                            )
+                        )
+            except Exception as exc:  # noqa: BLE001 — group-level failure
+                raise as_com_error(
+                    f"could not read from server {self._server!r} "
+                    "(group/level failure)",
+                    exc,
+                ) from None
+        finally:
+            # Release every COM reference INSIDE the apartment, in reverse
+            # creation order, before close()/CoUninitialize can see them.
+            live_items.clear()
+            items_collection = None
+            if group is not None:
+                try:
+                    group.Parent.OPCGroups.RemoveAll()
+                except Exception:  # noqa: BLE001 — best-effort cleanup
+                    pass
+            group = None
+        # preserve request order regardless of which tags failed to add
+        by_tag = {r.tag: r for r in results}
+        return [by_tag[tag] for tag in tags]
 
     def close(self) -> None:
         self._release_and_uninit()

src/opcda_diagnozer/opc/base.py

@@ -15,6 +15,7 @@ from __future__ import annotations
 from collections.abc import Sequence
 from dataclasses import dataclass
 from datetime import datetime
+from enum import IntEnum
 from typing import Any, Protocol, runtime_checkable
 
 
@@ -29,6 +30,19 @@ class ReadResult:
     error: str | None = None
 
 
+class OPCDataSource(IntEnum):
+    """Automation Wrapper data-source constants (OPCDataSource enum).
+
+    ``CACHE`` reads the server's last-known value (fast, may be stale),
+    ``DEVICE`` forces a round-trip to the underlying device/controller — the
+    one the diagnozer cares about (SPECIFICATION §10: the measured path is
+    server → device, not server → cache).
+    """
+
+    CACHE = 1
+    DEVICE = 2
+
+
 # Common HRESULTs the tool decodes and reports (README "DCOM troubleshooting").
 _HRESULT_NAMES: dict[int, str] = {
     0x800706BA: "RPC_S_SERVER_UNAVAILABLE — server process down, firewall, or DCOM activation refused",
@@ -38,7 +52,8 @@ _HRESULT_NAMES: dict[int, str] = {
     0x80040154: "REGDB_E_CLASSNOTREG — wrong ProgID, or wrapper/server registered under a different bitness",
     0x80020009: "DISP_E_EXCEPTION — the server rejected the call (e.g. no such branch/tag)",
     0x80070057: "E_INVALIDARG — invalid argument (e.g. wrong branch or item name)",
-    0xC0040007: "OPC_E_INVALIDITEMID — tag name wrong in config (surfaced by probe)",
+    0xC0040007: "OPC_E_UNKNOWNITEMID — the server does not know this tag",
+    0xC0040008: "OPC_E_INVALIDITEMID — tag name wrong in config (surfaced by probe)",
 }
 
 

src/opcda_diagnozer/opc/fake.py

@@ -15,7 +15,7 @@ from __future__ import annotations
 from collections.abc import Sequence
 from datetime import datetime, timezone
 
-from opcda_diagnozer.opc.base import Browser, OpcError, ReadResult, TagInfo
+from opcda_diagnozer.opc.base import Browser, OPCDataSource, OpcError, ReadResult, TagInfo
 
 #: The fake address space: branch path -> (sub-branches, leaf names).
 #: Mirrors the shape of a real SCADA server (Channel → Device → Tags).
@@ -99,15 +99,19 @@ class FakeOpcClient:
     """In-process :class:`OpcClient`; every read returns GOOD-quality zeros.
 
     ``space`` is injectable so tests can exercise flat namespaces, empty
-    servers, and deep trees; the default mirrors a Matrikon-like hierarchy.
+    servers, and deep trees; ``read_results`` scripts the next read() result
+    (Phase 1 scenario engine seed, IMPLEMENTATION_PLAN §4.9).
     """
 
     def __init__(
         self,
         space: dict[tuple[str, ...], tuple[tuple[str, ...], tuple[str, ...]]] | None = None,
+        read_results: list[ReadResult] | None = None,
     ) -> None:
         self.connected = False
         self._space = FAKE_SPACE if space is None else space
+        self._scripted_reads = read_results
+        self.reads: list[tuple[tuple[str, ...], OPCDataSource]] = []  # call log
 
     def connect(self) -> None:
         self.connected = True
@@ -117,9 +121,27 @@ class FakeOpcClient:
             raise OpcError("FakeOpcClient: create_browser() before connect()")
         return _FakeBrowser(self._space)
 
-    def read(self, tags: Sequence[str]) -> list[ReadResult]:
+    def read(
+        self, tags: Sequence[str], source: OPCDataSource = OPCDataSource.DEVICE
+    ) -> list[ReadResult]:
         if not self.connected:
             raise OpcError("FakeOpcClient: read() before connect()")
+        self.reads.append((tuple(tags), source))
+        if self._scripted_reads is not None:
+            scripted = {r.tag: r for r in self._scripted_reads}
+            return [
+                scripted.get(
+                    tag,
+                    ReadResult(
+                        tag=tag,
+                        value=None,
+                        quality_raw=0,
+                        device_time=None,
+                        error=f"no scripted result for {tag!r}",
+                    ),
+                )
+                for tag in tags
+            ]
         now = datetime.now(timezone.utc)
         return [
             ReadResult(tag=tag, value=0, quality_raw=0xC0, device_time=now)

tests/test_browse.py

@@ -221,7 +221,7 @@ def _run_cli(monkeypatch: pytest.MonkeyPatch, tmp_path, args: list[str]) -> int:
     )
     client = FakeOpcClient()
 
-    def _fake_connect(config_path: str):
+    def _fake_connect(config_path: str, server=None, host=None):
         client.connect()
         return client
 

tests/test_build_exe.py

@@ -0,0 +1,76 @@
+"""Tests for the frozen-exe build script + frozen-aware config default.
+
+The PyInstaller run itself is Windows-only and slow; these tests cover the
+pure logic the build script and the CLI rely on. The build script is
+PowerShell (``scripts/build_exe.ps1``); the tests assert on its content and
+on the CLI behaviors the produced exe depends on.
+"""
+
+import sys
+from pathlib import Path
+from unittest import mock
+
+import pytest
+
+from opcda_diagnozer.main import DEFAULT_CONFIG, _default_config_path
+
+BUILD_SCRIPT = Path(__file__).resolve().parents[1] / "scripts" / "build_exe.ps1"
+
+
+def test_default_config_path_in_source_mode() -> None:
+    """Not frozen: the default stays the plain relative name (CWD lookup)."""
+    with mock.patch.object(sys, "frozen", False, create=True):
+        assert _default_config_path() == DEFAULT_CONFIG
+
+
+def test_default_config_path_when_frozen_resolves_next_to_exe(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    """Frozen: config.yaml lives next to the exe — never the service CWD (System32)."""
+    exe_dir = tmp_path / "Program Files" / "OPCDA-Diagnozer"
+    exe_dir.mkdir(parents=True)
+    exe = exe_dir / "opcda-diagnozer.exe"
+    exe.touch()
+    monkeypatch.setattr(sys, "frozen", True, raising=False)
+    monkeypatch.setattr(sys, "executable", str(exe))
+    assert _default_config_path() == str(exe_dir / DEFAULT_CONFIG)
+
+
+@pytest.mark.skipif(sys.platform != "win32", reason="the exe is Windows-only")
+class TestBuildScript:
+    """Static assertions on scripts/build_exe.ps1 (no PyInstaller invocation)."""
+
+    def test_hidden_imports_cover_lazy_modules(self) -> None:
+        """Every lazy import in the package must be declared to PyInstaller."""
+        content = BUILD_SCRIPT.read_text(encoding="utf-8")
+        # the deferred COM imports (opc/automation.py, opc/discovery.py)
+        assert "'pythoncom'" in content
+        assert "'win32com.client'" in content
+        assert "'opcda_diagnozer.opc.automation'" in content
+        # the lazily-imported browse module (main.py verbs)
+        assert "'opcda_diagnozer.opc.browse'" in content
+        # the Phase 3 service host stays in the bundle from day one
+        assert "'opcda_diagnozer.service'" in content
+
+    def test_version_info_template_uses_pyi_keywords(self) -> None:
+        """The embedded version-info must use PyInstaller's exact keyword names.
+
+        FixedFileInfo.__init__ takes filevers/prodvers/mask/flags/OS/fileType/
+        subtype/date — anything else (fileVers, fileDate, subType) raises a
+        TypeError inside PyInstaller's eval at build time.
+        """
+        content = BUILD_SCRIPT.read_text(encoding="utf-8")
+        assert "filevers=(" in content
+        assert "fileType=0x1" in content
+        assert "subtype=0x0" in content
+        assert "date=(0, 0)" in content
+        # the rejected spellings must NOT appear
+        assert "fileVers=" not in content
+        assert "fileDate=" not in content
+        assert "subType=" not in content
+
+    def test_bitness_guards_present(self) -> None:
+        """The script must refuse a 64-bit interpreter and verify the PE."""
+        content = BUILD_SCRIPT.read_text(encoding="utf-8")
+        assert "struct.calcsize('P') * 8" in content  # interpreter bitness check
+        assert "0x14C" in content  # PE machine = IMAGE_FILE_MACHINE_I386 check

tests/test_config.py

@@ -18,7 +18,7 @@ def _write(tmp_path: Path, text: str) -> Path:
 def test_example_config_loads() -> None:
     config = load_config(EXAMPLE)
     assert config.opc.server == "Matrikon.OPC.Simulation.1"
-    assert config.opc.host == "CONTROL-HOST01"
+    assert config.opc.host is None  # host commented out -> local server
     assert len(config.tags) == 2
     assert config.tags[0].name == "Channel1.Device1.Counter"
     assert config.tags[0].expect_change is True

tests/test_read_cli.py

@@ -0,0 +1,210 @@
+"""Tests for the read/probe CLI verbs and the --server/--host overrides.
+
+All fake-client driven — no COM needed (IMPLEMENTATION_PLAN §9). The read path
+itself (OPCItem.Read) is verified live on a dev box with the Matrikon
+simulation server.
+"""
+
+import json
+import sys
+from datetime import datetime, timezone
+from pathlib import Path
+
+import pytest
+
+from opcda_diagnozer.main import main as cli_main
+from opcda_diagnozer.opc.base import OPCDataSource, OpcError, ReadResult
+from opcda_diagnozer.opc.fake import FakeOpcClient
+
+CONFIG = "opc:\n  server: Fake.Server.1\ntags:\n  - name: Bucket Brigade.Int1\n  - name: Bucket Brigade.Real8\n"
+
+
+def _run_cli(monkeypatch: pytest.MonkeyPatch, tmp_path: Path, args: list[str], client: FakeOpcClient | None = None) -> tuple[int, FakeOpcClient]:
+    """Run the CLI with the fake client injected in place of the COM adapter."""
+    import opcda_diagnozer.main as main_mod
+
+    config = tmp_path / "config.yaml"
+    config.write_text(CONFIG, encoding="utf-8")
+    fake = client if client is not None else FakeOpcClient()
+
+    def _fake_connect(config_path: str, server=None, host=None):
+        assert isinstance(server, str | None)
+        fake.connect()
+        return fake
+
+    monkeypatch.setattr(main_mod, "_connect_from_config", _fake_connect)
+    return cli_main(args), fake
+
+
+def test_read_explicit_tags(monkeypatch: pytest.MonkeyPatch, tmp_path: Path, capsys) -> None:
+    code, fake = _run_cli(monkeypatch, tmp_path, [
+        "read", "-c", str(tmp_path / "config.yaml"), "Bucket Brigade.Int1", "Bucket Brigade.Real8",
+    ])
+    out = capsys.readouterr().out
+    assert code == 0
+    assert "Bucket Brigade.Int1" in out
+    assert "0xC0" in out  # GOOD quality shown decoded
+    # request order preserved, source = DEVICE by default
+    assert fake.reads == [
+        (("Bucket Brigade.Int1", "Bucket Brigade.Real8"), OPCDataSource.DEVICE),
+    ]
+
+
+def test_read_from_config_tags(monkeypatch: pytest.MonkeyPatch, tmp_path: Path, capsys) -> None:
+    code, fake = _run_cli(monkeypatch, tmp_path, [
+        "read", "-c", str(tmp_path / "config.yaml"),
+    ])
+    out = capsys.readouterr().out
+    assert code == 0
+    assert "Bucket Brigade.Int1" in out and "Bucket Brigade.Real8" in out
+    assert fake.reads[0][0] == ("Bucket Brigade.Int1", "Bucket Brigade.Real8")
+
+
+def test_read_cache_source_flag(monkeypatch: pytest.MonkeyPatch, tmp_path: Path) -> None:
+    _, fake = _run_cli(monkeypatch, tmp_path, [
+        "read", "-c", str(tmp_path / "config.yaml"), "--source", "cache", "Bucket Brigade.Int1",
+    ])
+    assert fake.reads[0][1] == OPCDataSource.CACHE
+
+
+def test_read_json_output(monkeypatch: pytest.MonkeyPatch, tmp_path: Path, capsys) -> None:
+    code, _ = _run_cli(monkeypatch, tmp_path, [
+        "read", "-c", str(tmp_path / "config.yaml"), "--json", "Bucket Brigade.Int1",
+    ])
+    out = capsys.readouterr().out
+    assert code == 0
+    payload = json.loads(out.strip().splitlines()[0])
+    assert payload["tag"] == "Bucket Brigade.Int1"
+    assert payload["quality"] == "GOOD"
+    assert payload["quality_class"] == "GOOD"
+    assert payload["device_time_utc"]
+
+
+def test_read_bad_quality_tag_fails_with_nonzero_exit(
+    monkeypatch: pytest.MonkeyPatch, tmp_path: Path, capsys
+) -> None:
+    bad = ReadResult(
+        tag="Read Error.Int1",
+        value=None,
+        quality_raw=0x1C,  # BAD_OUT_OF_SERVICE (0x18 would be COMM_FAILURE)
+        device_time=datetime(2026, 10, 7, 9, 0, 0, tzinfo=timezone.utc),
+    )
+    code, _ = _run_cli(
+        monkeypatch, tmp_path,
+        ["read", "-c", str(tmp_path / "config.yaml"), "Read Error.Int1"],
+        client=FakeOpcClient(read_results=[bad]),
+    )
+    captured = capsys.readouterr()
+    assert code == 1  # non-GOOD quality -> exit 1
+    assert "BAD_OUT_OF_SERVICE" in captured.out
+    assert "did not read GOOD" in captured.err
+
+
+def test_read_error_tag_reports_error_not_crash(
+    monkeypatch: pytest.MonkeyPatch, tmp_path: Path, capsys
+) -> None:
+    missing = ReadResult(
+        tag="No.Such.Tag",
+        value=None,
+        quality_raw=0,
+        device_time=None,
+        error="cannot add tag 'No.Such.Tag' (HRESULT 0xC0040008: ...)",
+    )
+    code, _ = _run_cli(
+        monkeypatch, tmp_path,
+        ["read", "-c", str(tmp_path / "config.yaml"), "No.Such.Tag"],
+        client=FakeOpcClient(read_results=[missing]),
+    )
+    captured = capsys.readouterr()
+    assert code == 1
+    assert "ERROR" in captured.out
+    assert "0xC0040008" in captured.out
+
+
+def test_probe_reads_config_tags(monkeypatch: pytest.MonkeyPatch, tmp_path: Path, capsys) -> None:
+    code, fake = _run_cli(monkeypatch, tmp_path, [
+        "probe", "-c", str(tmp_path / "config.yaml"),
+    ])
+    out = capsys.readouterr().out
+    assert code == 0
+    assert fake.reads[0][0] == ("Bucket Brigade.Int1", "Bucket Brigade.Real8")
+    assert "Bucket Brigade.Int1" in out
+
+
+def test_probe_missing_config_is_actionable(
+    monkeypatch: pytest.MonkeyPatch, tmp_path: Path, capsys
+) -> None:
+    # no monkeypatching: the real _connect_from_config must produce the hint
+    code = cli_main(["probe", "-c", str(tmp_path / "no-such-config.yaml")])
+    captured = capsys.readouterr()
+    assert code == 2
+    assert "FAILED" in captured.err
+    assert "--server" in captured.err  # the hint points at the override
+
+
+def test_server_override_flows_to_client(
+    monkeypatch: pytest.MonkeyPatch, tmp_path: Path, capsys
+) -> None:
+    """--server/--host must reach the client even when a config exists."""
+    import opcda_diagnozer.main as main_mod
+
+    config = tmp_path / "config.yaml"
+    config.write_text(CONFIG, encoding="utf-8")
+    seen: dict[str, object] = {}
+
+    def _fake_connect(config_path: str, server=None, host=None):
+        seen["server"], seen["host"] = server, host
+        client = FakeOpcClient()
+        client.connect()
+        return client
+
+    monkeypatch.setattr(main_mod, "_connect_from_config", _fake_connect)
+    code = cli_main([
+        "read", "-c", str(config),
+        "--server", "Other.Server.1", "--host", "OTHER-HOST",
+        "Some.Tag",
+    ])
+    assert code == 0
+    assert seen == {"server": "Other.Server.1", "host": "OTHER-HOST"}
+
+
+def test_read_without_config_and_without_server_is_actionable(
+    monkeypatch: pytest.MonkeyPatch, tmp_path: Path, capsys
+) -> None:
+    # no monkeypatching: the real connect path must fail with the hint
+    code = cli_main([
+        "read", "-c", str(tmp_path / "no-such.yaml"), "Some.Tag",
+    ])
+    captured = capsys.readouterr()
+    assert code == 2
+    assert "--server" in captured.err
+
+
+@pytest.mark.skipif(sys.platform != "win32", reason="live read needs Windows + pywin32")
+def test_live_automation_read_smoke() -> None:
+    """Live smoke test — requires the Matrikon simulation server on this dev box."""
+    pytest.importorskip("pythoncom")
+    from opcda_diagnozer.opc.automation import AutomationOpcClient
+
+    client = AutomationOpcClient(server="Matrikon.OPC.Simulation.1")
+    try:
+        client.connect()
+        results = client.read(
+            ["Bucket Brigade.Int1", "Read Error.Int1", "No.Such.Tag"],
+            source=OPCDataSource.DEVICE,
+        )
+        by_tag = {r.tag: r for r in results}
+        good = by_tag["Bucket Brigade.Int1"]
+        assert good.quality_raw == 0xC0
+        assert good.device_time is not None
+        # unknown tag -> per-tag error, never an exception
+        assert by_tag["No.Such.Tag"].error is not None
+        # "Read Error.Int1" from DEVICE returns the error code as the value
+        # with GOOD quality (verified live 2026-10-07); the BAD quality only
+        # appears on the CACHE path — the diagnozer's quality monitoring
+        # therefore reads CACHE for that tag in the poll loop (Phase 1).
+        assert by_tag["Read Error.Int1"].value is not None
+    except OpcError as exc:
+        pytest.skip(f"simulation server not usable on this machine: {exc}")
+    finally:
+        client.close()