diff --git a/.agent-work/ledger.json b/.agent-work/ledger.json
new file mode 100644
index 0000000..84d6e0c
--- /dev/null
+++ b/.agent-work/ledger.json
@@ -0,0 +1,9 @@
+{
+  "tasks": {
+    "projects/product-54354138-1#3": {
+      "events": [
+        "Created tools package (tools/__init__.py, tools/example.py), examples/input.json, tests/test_example.py, .gitignore, .env.example; updated pyproject.toml (metadata, setuptools packages, dev pytest extra, pytest pythonpath/testpaths, requires-python >=3.11 due to approved-mirror exceptiongroup constraint) and generated uv.lock via prepare_environment update. Facade validate/test/smoke and --help all pass locally."
+      ]
+    }
+  }
+}
diff --git a/.env.example b/.env.example
new file mode 100644
index 0000000..a827b65
--- /dev/null
+++ b/.env.example
@@ -0,0 +1,3 @@
+# Optional environment overrides for the toolkit CLI.
+# The CLI is offline and does not require any variable to be set.
+LOG_LEVEL=info
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..f01c06e
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,7 @@
+__pycache__/
+*.py[cod]
+.venv/
+.pytest_cache/
+build/
+dist/
+*.egg-info/
diff --git a/examples/input.json b/examples/input.json
new file mode 100644
index 0000000..6ed9590
--- /dev/null
+++ b/examples/input.json
@@ -0,0 +1,9 @@
+{
+  "version": 1,
+  "mode": "validate",
+  "dry_run": true,
+  "command": "example",
+  "arguments": {
+    "request": "examples/input.json"
+  }
+}
diff --git a/pyproject.toml b/pyproject.toml
index 13a7c65..af98515 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,8 +1,23 @@
-# Initial declaration; add project dependencies and development tools here.
+[build-system]
+requires = ["setuptools>=68"]
+build-backend = "setuptools.build_meta"
+
 [project]
 name = "product-54354138-1-tools"
 version = "0.1.0"
+description = "Offline toolkit for validating and running structured JSON request documents."
+readme = "README.md"
+requires-python = ">=3.11"
 dependencies = []
 
 [project.optional-dependencies]
-dev = ["pytest"]
+dev = ["pytest>=8.0"]
+
+[tool.setuptools]
+packages = ["tools"]
+
+[tool.pytest.ini_options]
+minversion = "8.0"
+pythonpath = ["."]
+testpaths = ["tests"]
+addopts = "-ra"
diff --git a/tests/test_example.py b/tests/test_example.py
new file mode 100644
index 0000000..1574b48
--- /dev/null
+++ b/tests/test_example.py
@@ -0,0 +1,118 @@
+"""Tests for the placeholder toolkit CLI and its request document."""
+
+from __future__ import annotations
+
+import json
+import subprocess
+import sys
+from pathlib import Path
+
+import pytest
+
+from tools import example
+
+REPO_ROOT = Path(__file__).resolve().parents[1]
+EXAMPLE_REQUEST = REPO_ROOT / "examples" / "input.json"
+
+
+def run_cli(*args: str) -> subprocess.CompletedProcess[str]:
+    """Run the CLI in a subprocess so stdout/exit codes are asserted end to end."""
+    return subprocess.run(
+        [sys.executable, "-m", "tools.example", *args],
+        cwd=REPO_ROOT,
+        capture_output=True,
+        text=True,
+        check=False,
+    )
+
+
+def test_example_request_document_is_valid_json_object() -> None:
+    document = json.loads(EXAMPLE_REQUEST.read_text(encoding="utf-8"))
+
+    assert isinstance(document, dict)
+    assert set(example.REQUIRED_FIELDS) <= set(document)
+    assert document["dry_run"] is True
+    assert document["mode"] == "validate"
+
+
+def test_example_request_document_passes_validation() -> None:
+    request = example.validate_request(example.load_request(EXAMPLE_REQUEST))
+
+    assert request["mode"] == "validate"
+    assert request["dry_run"] is True
+    assert request["arguments"]["request"] == "examples/input.json"
+
+
+def test_cli_prints_single_json_envelope_and_exits_zero() -> None:
+    result = run_cli("examples/input.json")
+
+    assert result.returncode == 0, result.stderr
+    assert result.stderr == ""
+    lines = [line for line in result.stdout.splitlines() if line.strip()]
+    assert len(lines) == 1
+
+    envelope = json.loads(lines[0])
+    assert envelope == {
+        "status": "ok",
+        "command": "example",
+        "mode": "validate",
+        "dry_run": True,
+        "version": 1,
+        "request": "examples/input.json",
+    }
+
+
+def test_cli_help_exits_zero() -> None:
+    result = run_cli("--help")
+
+    assert result.returncode == 0
+    assert "REQUEST" in result.stdout
+
+
+def test_cli_reports_missing_request_document(tmp_path: Path) -> None:
+    missing = tmp_path / "missing.json"
+
+    result = run_cli(str(missing))
+
+    assert result.returncode == example.EXIT_INVALID_REQUEST
+    envelope = json.loads(result.stdout)
+    assert envelope["status"] == "error"
+    assert envelope["error"]["code"] == "request_not_found"
+
+
+def test_cli_reports_malformed_json(tmp_path: Path) -> None:
+    malformed = tmp_path / "malformed.json"
+    malformed.write_text("{not json", encoding="utf-8")
+
+    result = run_cli(str(malformed))
+
+    assert result.returncode == example.EXIT_INVALID_REQUEST
+    assert json.loads(result.stdout)["error"]["code"] == "request_not_json"
+
+
+@pytest.mark.parametrize(
+    ("document", "code"),
+    [
+        ([], "request_not_object"),
+        ({"mode": "validate", "dry_run": True, "command": "example", "arguments": {}}, "request_field_missing"),
+        ({"version": 1, "mode": "validate", "dry_run": False, "command": "example", "arguments": {"request": "x"}}, "request_not_dry_run"),
+        ({"version": 1, "mode": "execute", "dry_run": True, "command": "example", "arguments": {"request": "x"}}, "request_mode_unsupported"),
+        ({"version": 1, "mode": "validate", "dry_run": True, "command": "example", "arguments": {}}, "request_field_missing"),
+        ({"version": 1, "mode": "validate", "dry_run": True, "command": "", "arguments": {"request": "x"}}, "request_field_invalid"),
+    ],
+)
+def test_validate_request_rejects_invalid_documents(document: object, code: str) -> None:
+    with pytest.raises(example.RequestError) as excinfo:
+        example.validate_request(document)
+
+    assert excinfo.value.code == code
+
+
+def test_envelope_is_deterministic() -> None:
+    request = example.validate_request(example.load_request(EXAMPLE_REQUEST))
+
+    first = example.build_envelope(request, "examples/input.json")
+    second = example.build_envelope(request, "examples/input.json")
+
+    assert first == second
+    assert json.dumps(first, sort_keys=True) == json.dumps(second, sort_keys=True)
diff --git a/tools/__init__.py b/tools/__init__.py
new file mode 100644
index 0000000..a1c96b3
--- /dev/null
+++ b/tools/__init__.py
@@ -0,0 +1,12 @@
+"""Importable toolkit package for the request-document CLI.
+
+The package intentionally exposes only its version metadata here; the
+executable behaviour lives in :mod:`tools.example` (and in the modules that
+later increments add).
+"""
+
+from __future__ import annotations
+
+__all__ = ["__version__"]
+
+__version__ = "0.1.0"
diff --git a/tools/example.py b/tools/example.py
new file mode 100644
index 0000000..32d2b87
--- /dev/null
+++ b/tools/example.py
@@ -0,0 +1,200 @@
+"""Placeholder toolkit entry point that loads and validates a JSON request.
+
+This increment only establishes the stable command-line surface: read a single
+JSON request document, validate its shape, and print one structured JSON
+envelope. Later modules extend the same document format and envelope without
+changing the invocation contract, so the module stays deterministic and works
+fully offline.
+
+Usage::
+
+    python -m tools.example examples/input.json
+"""
+
+from __future__ import annotations
+
+import argparse
+import json
+import sys
+from pathlib import Path
+from typing import Any, Mapping, Sequence
+
+__all__ = [
+    "EXIT_INVALID_REQUEST",
+    "EXIT_OK",
+    "EXIT_USAGE",
+    "RequestError",
+    "build_envelope",
+    "load_request",
+    "main",
+    "validate_request",
+]
+
+EXIT_OK = 0
+EXIT_INVALID_REQUEST = 1
+EXIT_USAGE = 2
+
+#: Fields every request document must provide.
+REQUIRED_FIELDS = ("version", "mode", "dry_run", "command", "arguments")
+
+#: Modes understood by this increment of the toolkit.
+SUPPORTED_MODES = frozenset({"validate"})
+
+PROG = "tools.example"
+
+
+class RequestError(ValueError):
+    """Raised when a request document is missing or malformed."""
+
+    def __init__(self, code: str, message: str) -> None:
+        super().__init__(message)
+        self.code = code
+        self.message = message
+
+
+def load_request(path: str | Path) -> Any:
+    """Read and decode the JSON document stored at ``path``."""
+    try:
+        raw = Path(path).read_text(encoding="utf-8")
+    except FileNotFoundError as exc:
+        raise RequestError("request_not_found", f"request document not found: {path}") from exc
+    except IsADirectoryError as exc:
+        raise RequestError("request_not_a_file", f"request document is not a file: {path}") from exc
+    except OSError as exc:
+        raise RequestError("request_unreadable", f"request document could not be read: {path}") from exc
+    except UnicodeDecodeError as exc:
+        raise RequestError("request_not_utf8", f"request document is not valid UTF-8: {path}") from exc
+
+    try:
+        return json.loads(raw)
+    except json.JSONDecodeError as exc:
+        raise RequestError(
+            "request_not_json",
+            f"request document is not valid JSON: {path} (line {exc.lineno}, column {exc.colno})",
+        ) from exc
+
+
+def _require(mapping: Mapping[str, Any], key: str, expected: type | tuple[type, ...], label: str) -> Any:
+    if key not in mapping:
+        raise RequestError("request_field_missing", f"request field {label} is required")
+    value = mapping[key]
+    if isinstance(value, bool) and bool not in (
+        expected if isinstance(expected, tuple) else (expected,)
+    ):
+        raise RequestError("request_field_invalid", f"request field {label} must be {_describe(expected)}")
+    if not isinstance(value, expected):
+        raise RequestError("request_field_invalid", f"request field {label} must be {_describe(expected)}")
+    return value
+
+
+def _describe(expected: type | tuple[type, ...]) -> str:
+    names = expected if isinstance(expected, tuple) else (expected,)
+    return " or ".join(sorted({name.__name__ for name in names}))
+
+
+def validate_request(document: Any) -> dict[str, Any]:
+    """Validate ``document`` and return the normalised request mapping."""
+    if not isinstance(document, dict):
+        raise RequestError("request_not_object", "request document must be a JSON object")
+
+    for key in REQUIRED_FIELDS:
+        if key not in document:
+            raise RequestError("request_field_missing", f"request field '{key}' is required")
+
+    version = _require(document, "version", int, "version")
+    if version < 1:
+        raise RequestError("request_field_invalid", "request field 'version' must be a positive integer")
+
+    mode = _require(document, "mode", str, "mode")
+    if mode not in SUPPORTED_MODES:
+        supported = ", ".join(sorted(SUPPORTED_MODES))
+        raise RequestError(
+            "request_mode_unsupported",
+            f"request field 'mode' must be one of: {supported}",
+        )
+
+    dry_run = _require(document, "dry_run", bool, "dry_run")
+    if not dry_run:
+        raise RequestError(
+            "request_not_dry_run",
+            "this increment only supports validate-only dry_run requests",
+        )
+
+    command = _require(document, "command", str, "command")
+    if not command.strip():
+        raise RequestError("request_field_invalid", "request field 'command' must not be empty")
+
+    arguments = _require(document, "arguments", dict, "arguments")
+    request_path = _require(arguments, "request", str, "arguments.request")
+    if not request_path.strip():
+        raise RequestError("request_field_invalid", "request field 'arguments.request' must not be empty")
+
+    return {
+        "version": version,
+        "mode": mode,
+        "dry_run": dry_run,
+        "command": command,
+        "arguments": dict(arguments),
+    }
+
+
+def build_envelope(request: Mapping[str, Any], source: str) -> dict[str, Any]:
+    """Build the deterministic success envelope for a validated request."""
+    return {
+        "status": "ok",
+        "command": request["command"],
+        "mode": request["mode"],
+        "dry_run": request["dry_run"],
+        "version": request["version"],
+        "request": source,
+    }
+
+
+def build_error_envelope(error: RequestError, source: str) -> dict[str, Any]:
+    """Build the deterministic failure envelope for an invalid request."""
+    return {
+        "status": "error",
+        "error": {"code": error.code, "message": error.message},
+        "request": source,
+    }
+
+
+def emit(envelope: Mapping[str, Any]) -> None:
+    """Print exactly one JSON document to standard output."""
+    print(json.dumps(envelope, sort_keys=True, ensure_ascii=True))
+
+
+def _build_parser() -> argparse.ArgumentParser:
+    parser = argparse.ArgumentParser(
+        prog=PROG,
+        description=(
+            "Load and validate a JSON request document. The command is offline "
+            "and prints one structured JSON envelope."
+        ),
+    )
+    parser.add_argument(
+        "request",
+        metavar="REQUEST",
+        help="path to the JSON request document (for example examples/input.json)",
+    )
+    return parser
+
+
+def main(argv: Sequence[str] | None = None) -> int:
+    """Run the placeholder CLI and return the process exit code."""
+    parser = _build_parser()
+    args = parser.parse_args(list(sys.argv[1:] if argv is None else argv))
+
+    try:
+        document = load_request(args.request)
+        request = validate_request(document)
+    except RequestError as error:
+        emit(build_error_envelope(error, args.request))
+        return EXIT_INVALID_REQUEST
+
+    emit(build_envelope(request, args.request))
+    return EXIT_OK
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())
diff --git a/uv.lock b/uv.lock
new file mode 100644
index 0000000..587cd93
--- /dev/null
+++ b/uv.lock
@@ -0,0 +1,63 @@
+version = 1
+revision = 5
+requires-python = ">=3.11"
+
+[[package]]
+name = "colorama"
+version = "0.4.6"
+source = { registry = "https://git.p2prod.ru/api/packages/dependency-mirror/pypi/simple" }
+wheels = [
+    { url = "https://git.p2prod.ru/api/packages/dependency-mirror/pypi/files/colorama/0.4.6/colorama-0.4.6-py2.py3-none-any.whl", hash = "sha256:4f1d9991f5acc0ca119f9d443620b77f9d6b33703e51011c16baf57afb285fc6" },
+]
+
+[[package]]
+name = "iniconfig"
+version = "2.3.1"
+source = { registry = "https://git.p2prod.ru/api/packages/dependency-mirror/pypi/simple" }
+wheels = [
+    { url = "https://git.p2prod.ru/api/packages/dependency-mirror/pypi/files/iniconfig/2.3.1/iniconfig-2.3.1-py3-none-any.whl", hash = "sha256:9121e2c1fdb355232495be3194c8dfe87ccc2d5dee45947b78e68f499790d7a7" },
+]
+
+[[package]]
+name = "packaging"
+version = "26.3"
+source = { registry = "https://git.p2prod.ru/api/packages/dependency-mirror/pypi/simple" }
+wheels = [
+    { url = "https://git.p2prod.ru/api/packages/dependency-mirror/pypi/files/packaging/26.3/packaging-26.3-py3-none-any.whl", hash = "sha256:d7193f7c8e4e93f444fde0262bf90af30e16fa0ad0ad44cb553c87339b23cd1c" },
+]
+
+[[package]]
+name = "pluggy"
+version = "1.7.0"
+source = { registry = "https://git.p2prod.ru/api/packages/dependency-mirror/pypi/simple" }
+wheels = [
+    { url = "https://git.p2prod.ru/api/packages/dependency-mirror/pypi/files/pluggy/1.7.0/pluggy-1.7.0-py3-none-any.whl", hash = "sha256:7dd7b0d8832ba3cb632c306926ded123429211b83641b35dc5c41ad2d34f9bec" },
+]
+
+[[package]]
+name = "product-54354138-1-tools"
+version = "0.1.0"
+source = { editable = "." }
+
+[package.optional-dependencies]
+dev = [
+    { name = "pytest" },
+]
+
+[package.metadata]
+requires-dist = [{ name = "pytest", marker = "extra == 'dev'", specifier = ">=8.0" }]
+provides-extras = ["dev"]
+
+[[package]]
+name = "pytest"
+version = "8.3.3"
+source = { registry = "https://git.p2prod.ru/api/packages/dependency-mirror/pypi/simple" }
+dependencies = [
+    { name = "colorama", marker = "sys_platform == 'win32'" },
+    { name = "iniconfig" },
+    { name = "packaging" },
+    { name = "pluggy" },
+]
+wheels = [
+    { url = "https://git.p2prod.ru/api/packages/dependency-mirror/pypi/files/pytest/8.3.3/pytest-8.3.3-py3-none-any.whl", hash = "sha256:a6853c7375b2663155079443d2e45de913a911a11d669df02a50814944db57b2" },
+]