From 70d20f0f182fddd73a03b88ac2a3565e5ead6087 Mon Sep 17 00:00:00 2001
From: Jan Nedbal <jan.nedbal@apertia.cz>
Date: Tue, 14 Apr 2026 22:30:45 +0200
Subject: [PATCH 1/7] cli: add m2pack binary discovery helper

Resolve the m2pack-secure binary via M2PACK_BINARY env var or PATH,
raising ValidationError(m2pack_not_found) when neither works.
---
 src/metin_release/m2pack_binary.py | 51 ++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)
 create mode 100644 src/metin_release/m2pack_binary.py

diff --git a/src/metin_release/m2pack_binary.py b/src/metin_release/m2pack_binary.py
new file mode 100644
index 0000000..1ce41c9
--- /dev/null
+++ b/src/metin_release/m2pack_binary.py
@@ -0,0 +1,51 @@
+"""Resolve the m2pack binary for the m2pack wrapper subcommands.
+
+Resolution order:
+
+1. ``M2PACK_BINARY`` environment variable, if set, non-empty, and points at
+   an existing file.
+2. :func:`shutil.which` on ``m2pack``.
+
+If neither works we raise :class:`~metin_release.errors.ValidationError` so
+the CLI exits 1 with a clear, actionable message. Import of this module
+must never trigger filesystem access — all discovery is runtime.
+"""
+
+from __future__ import annotations
+
+import os
+import shutil
+from pathlib import Path
+
+from .errors import ValidationError
+
+
+ENV_VAR = "M2PACK_BINARY"
+
+_NOT_FOUND_HINT = (
+    "m2pack binary not found. Set the M2PACK_BINARY environment variable to "
+    "an absolute path, or make `m2pack` available on PATH. Build it from "
+    "https://gitea.jakubkadlec.dev/metin-server/m2pack-secure (see its "
+    "CMakeLists.txt)."
+)
+
+
+def resolve_m2pack_binary(env: dict[str, str] | None = None) -> Path:
+    """Return the resolved path to the m2pack binary or raise ValidationError."""
+    environ = env if env is not None else os.environ
+    override = (environ.get(ENV_VAR) or "").strip()
+    if override:
+        candidate = Path(override).expanduser()
+        if candidate.is_file():
+            return candidate.resolve()
+        raise ValidationError(
+            f"{ENV_VAR}={override!r} does not point at an existing file. "
+            f"{_NOT_FOUND_HINT}",
+            error_code="m2pack_not_found",
+        )
+
+    which = shutil.which("m2pack")
+    if which:
+        return Path(which).resolve()
+
+    raise ValidationError(_NOT_FOUND_HINT, error_code="m2pack_not_found")

From ae0cbb7e9bcc2dbf028e19d9892c9f2acc7abe49 Mon Sep 17 00:00:00 2001
From: Jan Nedbal <jan.nedbal@apertia.cz>
Date: Tue, 14 Apr 2026 22:30:51 +0200
Subject: [PATCH 2/7] cli: implement m2pack build and verify wrappers

Shell out to m2pack-secure with --json, parse its envelope, and
translate into the standard metin-release Result envelope under
data.m2pack. Non-zero exit and non-JSON output map to SubprocessError
with m2pack_failed / m2pack_invalid_json / m2pack_empty_output codes.
---
 src/metin_release/commands/_m2pack_runner.py | 78 ++++++++++++++++++++
 src/metin_release/commands/m2pack_build.py   | 47 ++++++++++++
 src/metin_release/commands/m2pack_verify.py  | 45 +++++++++++
 3 files changed, 170 insertions(+)
 create mode 100644 src/metin_release/commands/_m2pack_runner.py
 create mode 100644 src/metin_release/commands/m2pack_build.py
 create mode 100644 src/metin_release/commands/m2pack_verify.py

diff --git a/src/metin_release/commands/_m2pack_runner.py b/src/metin_release/commands/_m2pack_runner.py
new file mode 100644
index 0000000..018d63a
--- /dev/null
+++ b/src/metin_release/commands/_m2pack_runner.py
@@ -0,0 +1,78 @@
+"""Shared helper to invoke the real m2pack CLI and translate its JSON.
+
+m2pack-secure emits its own JSON envelopes with ``--json``. Their shape is
+not identical to our :class:`~metin_release.result.Result` envelope, so we
+wrap the raw dict under ``data["m2pack"]`` and promote a few well-known
+fields (artifact paths, counts) where it makes sense per command.
+
+If m2pack exits non-zero or prints non-JSON, we raise
+:class:`~metin_release.errors.SubprocessError` so the CLI exits with code
+1 and a readable error envelope.
+"""
+
+from __future__ import annotations
+
+import json
+import subprocess
+from pathlib import Path
+from typing import Any
+
+from ..errors import SubprocessError
+from ..log import get_logger
+from ..m2pack_binary import resolve_m2pack_binary
+
+
+def run_m2pack(subcommand: str, argv: list[str]) -> dict[str, Any]:
+    """Invoke ``m2pack <subcommand> [argv...] --json`` and return parsed JSON.
+
+    Raises :class:`SubprocessError` (exit code 1) on any failure: binary
+    missing, non-zero exit, empty stdout, or non-JSON stdout. Missing
+    binary is handled inside :func:`resolve_m2pack_binary` by raising a
+    :class:`~metin_release.errors.ValidationError` which the dispatcher
+    already converts into the standard error envelope.
+    """
+    log = get_logger()
+    binary: Path = resolve_m2pack_binary()
+    cmd = [str(binary), subcommand, *argv, "--json"]
+    log.debug("running m2pack: %s", " ".join(cmd))
+    try:
+        proc = subprocess.run(
+            cmd, capture_output=True, text=True, check=False
+        )
+    except OSError as exc:
+        raise SubprocessError(
+            f"failed to spawn m2pack: {exc}",
+            error_code="m2pack_spawn_failed",
+        ) from exc
+
+    stdout = (proc.stdout or "").strip()
+    stderr = (proc.stderr or "").strip()
+
+    if proc.returncode != 0:
+        detail = stderr or stdout or f"exit code {proc.returncode}"
+        raise SubprocessError(
+            f"m2pack {subcommand} failed (rc={proc.returncode}): {detail}",
+            error_code="m2pack_failed",
+        )
+
+    if not stdout:
+        raise SubprocessError(
+            f"m2pack {subcommand} produced no stdout; stderr={stderr!r}",
+            error_code="m2pack_empty_output",
+        )
+
+    try:
+        parsed = json.loads(stdout)
+    except json.JSONDecodeError as exc:
+        raise SubprocessError(
+            f"m2pack {subcommand} returned non-JSON output: {exc}; "
+            f"first 200 chars={stdout[:200]!r}",
+            error_code="m2pack_invalid_json",
+        ) from exc
+
+    if not isinstance(parsed, dict):
+        raise SubprocessError(
+            f"m2pack {subcommand} JSON was not an object: {type(parsed).__name__}",
+            error_code="m2pack_invalid_json",
+        )
+    return parsed
diff --git a/src/metin_release/commands/m2pack_build.py b/src/metin_release/commands/m2pack_build.py
new file mode 100644
index 0000000..9eb28d5
--- /dev/null
+++ b/src/metin_release/commands/m2pack_build.py
@@ -0,0 +1,47 @@
+"""m2pack build: wrap ``m2pack build`` to produce a signed .m2p archive."""
+
+from __future__ import annotations
+
+import argparse
+from pathlib import Path
+
+from ..result import Result
+from ._m2pack_runner import run_m2pack
+
+
+def add_parser(sub: argparse._SubParsersAction) -> argparse.ArgumentParser:
+    p = sub.add_parser("build", help="Build a signed .m2p archive from a source directory.")
+    p.add_argument("--input", required=True, type=Path, help="Client asset source directory.")
+    p.add_argument("--output", required=True, type=Path, help="Output .m2p archive path.")
+    p.add_argument("--key", required=True, type=Path, help="Master content key file.")
+    p.add_argument(
+        "--sign-secret-key",
+        required=True,
+        type=Path,
+        help="Ed25519 signing secret key file.",
+    )
+    p.add_argument("--key-id", type=int, help="Content key id (default 1).")
+    return p
+
+
+def run(ctx, args: argparse.Namespace) -> Result:
+    argv = [
+        "--input", str(args.input),
+        "--output", str(args.output),
+        "--key", str(args.key),
+        "--sign-secret-key", str(args.sign_secret_key),
+    ]
+    if args.key_id is not None:
+        argv.extend(["--key-id", str(args.key_id)])
+
+    raw = run_m2pack("build", argv)
+    status = "built" if raw.get("ok", True) else "failed"
+    return Result(
+        command="m2pack build",
+        ok=bool(raw.get("ok", True)),
+        status=status,
+        data={
+            "artifacts": {"archive_path": str(args.output)},
+            "m2pack": raw,
+        },
+    )
diff --git a/src/metin_release/commands/m2pack_verify.py b/src/metin_release/commands/m2pack_verify.py
new file mode 100644
index 0000000..c34d11c
--- /dev/null
+++ b/src/metin_release/commands/m2pack_verify.py
@@ -0,0 +1,45 @@
+"""m2pack verify: wrap ``m2pack verify`` to validate manifest + optional decrypt."""
+
+from __future__ import annotations
+
+import argparse
+from pathlib import Path
+
+from ..result import Result
+from ._m2pack_runner import run_m2pack
+
+
+def add_parser(sub: argparse._SubParsersAction) -> argparse.ArgumentParser:
+    p = sub.add_parser("verify", help="Verify an .m2p archive (manifest + signature).")
+    p.add_argument("--archive", required=True, type=Path, help="Path to .m2p archive.")
+    p.add_argument(
+        "--public-key",
+        type=Path,
+        help="Ed25519 public key file (for signature verification).",
+    )
+    p.add_argument(
+        "--key",
+        type=Path,
+        help="Master content key file (enables full-decrypt verification).",
+    )
+    return p
+
+
+def run(ctx, args: argparse.Namespace) -> Result:
+    argv = ["--archive", str(args.archive)]
+    if args.public_key is not None:
+        argv.extend(["--public-key", str(args.public_key)])
+    if args.key is not None:
+        argv.extend(["--key", str(args.key)])
+
+    raw = run_m2pack("verify", argv)
+    ok = bool(raw.get("ok", True))
+    return Result(
+        command="m2pack verify",
+        ok=ok,
+        status="verified" if ok else "failed",
+        data={
+            "artifacts": {"archive_path": str(args.archive)},
+            "m2pack": raw,
+        },
+    )

From 197c5ba8a29cc51089d0f80d0f56e065d55541fc Mon Sep 17 00:00:00 2001
From: Jan Nedbal <jan.nedbal@apertia.cz>
Date: Tue, 14 Apr 2026 22:30:56 +0200
Subject: [PATCH 3/7] cli: implement m2pack diff and export-runtime-key
 wrappers

diff promotes m2pack's added/removed/changed/unchanged counts into
data.stats when m2pack reports them as lists or ints. export-runtime-key
follows the real binary's --key/--public-key/--output/--key-id/--format
surface (not the original plan's --pack/--master-key).
---
 src/metin_release/commands/m2pack_diff.py     | 45 +++++++++++++++
 .../commands/m2pack_export_runtime_key.py     | 57 +++++++++++++++++++
 2 files changed, 102 insertions(+)
 create mode 100644 src/metin_release/commands/m2pack_diff.py
 create mode 100644 src/metin_release/commands/m2pack_export_runtime_key.py

diff --git a/src/metin_release/commands/m2pack_diff.py b/src/metin_release/commands/m2pack_diff.py
new file mode 100644
index 0000000..4eebf11
--- /dev/null
+++ b/src/metin_release/commands/m2pack_diff.py
@@ -0,0 +1,45 @@
+"""m2pack diff: wrap ``m2pack diff`` to compare directories and/or .m2p archives."""
+
+from __future__ import annotations
+
+import argparse
+from pathlib import Path
+
+from ..result import Result
+from ._m2pack_runner import run_m2pack
+
+
+def add_parser(sub: argparse._SubParsersAction) -> argparse.ArgumentParser:
+    p = sub.add_parser(
+        "diff",
+        help="Diff two directories and/or .m2p archives (left vs right).",
+    )
+    p.add_argument("--left", required=True, type=Path, help="Left side: directory or .m2p archive.")
+    p.add_argument("--right", required=True, type=Path, help="Right side: directory or .m2p archive.")
+    return p
+
+
+def run(ctx, args: argparse.Namespace) -> Result:
+    argv = ["--left", str(args.left), "--right", str(args.right)]
+    raw = run_m2pack("diff", argv)
+
+    # Best-effort promotion of the diff counts m2pack reports. Fall back
+    # gracefully when the key is missing or the shape differs.
+    stats: dict[str, object] = {}
+    for key in ("added", "removed", "changed", "unchanged"):
+        value = raw.get(key)
+        if isinstance(value, int):
+            stats[f"{key}_count"] = value
+        elif isinstance(value, list):
+            stats[f"{key}_count"] = len(value)
+
+    ok = bool(raw.get("ok", True))
+    return Result(
+        command="m2pack diff",
+        ok=ok,
+        status="diffed" if ok else "failed",
+        data={
+            "stats": stats,
+            "m2pack": raw,
+        },
+    )
diff --git a/src/metin_release/commands/m2pack_export_runtime_key.py b/src/metin_release/commands/m2pack_export_runtime_key.py
new file mode 100644
index 0000000..78773e0
--- /dev/null
+++ b/src/metin_release/commands/m2pack_export_runtime_key.py
@@ -0,0 +1,57 @@
+"""m2pack export-runtime-key: wrap ``m2pack export-runtime-key``.
+
+Emits a launcher runtime-key payload in either ``json`` or ``blob`` form
+from the master content key + signing public key. The plan originally
+described this as ``--pack --master-key --out``; the real m2pack CLI
+uses ``--key --public-key --key-id --format --output``, so we follow the
+real tool.
+"""
+
+from __future__ import annotations
+
+import argparse
+from pathlib import Path
+
+from ..result import Result
+from ._m2pack_runner import run_m2pack
+
+
+def add_parser(sub: argparse._SubParsersAction) -> argparse.ArgumentParser:
+    p = sub.add_parser(
+        "export-runtime-key",
+        help="Export a launcher runtime-key payload (json or blob form).",
+    )
+    p.add_argument("--key", required=True, type=Path, help="Master content key file.")
+    p.add_argument("--public-key", required=True, type=Path, help="Ed25519 public key file.")
+    p.add_argument("--output", required=True, type=Path, help="Output payload path.")
+    p.add_argument("--key-id", type=int, help="Content key id (default 1).")
+    p.add_argument(
+        "--format",
+        choices=("json", "blob"),
+        help="Payload format (default json).",
+    )
+    return p
+
+
+def run(ctx, args: argparse.Namespace) -> Result:
+    argv = [
+        "--key", str(args.key),
+        "--public-key", str(args.public_key),
+        "--output", str(args.output),
+    ]
+    if args.key_id is not None:
+        argv.extend(["--key-id", str(args.key_id)])
+    if args.format is not None:
+        argv.extend(["--format", args.format])
+
+    raw = run_m2pack("export-runtime-key", argv)
+    ok = bool(raw.get("ok", True))
+    return Result(
+        command="m2pack export-runtime-key",
+        ok=ok,
+        status="exported" if ok else "failed",
+        data={
+            "artifacts": {"runtime_key_path": str(args.output)},
+            "m2pack": raw,
+        },
+    )

From a289cd7c25415f56ad835d0cd0ab24ef491a624e Mon Sep 17 00:00:00 2001
From: Jan Nedbal <jan.nedbal@apertia.cz>
Date: Tue, 14 Apr 2026 22:31:00 +0200
Subject: [PATCH 4/7] cli: add m2pack command group to dispatcher

Register the m2pack subparser and wire build/verify/diff/export-runtime-key
into _COMMAND_MAP alongside the existing release group.
---
 src/metin_release/cli.py               | 23 +++++++++++++++++++++++
 src/metin_release/commands/__init__.py |  8 ++++++++
 2 files changed, 31 insertions(+)

diff --git a/src/metin_release/cli.py b/src/metin_release/cli.py
index 9b85ae5..6a7320b 100644
--- a/src/metin_release/cli.py
+++ b/src/metin_release/cli.py
@@ -11,6 +11,10 @@ from .commands import (
     build_manifest,
     diff_remote,
     inspect,
+    m2pack_build,
+    m2pack_diff,
+    m2pack_export_runtime_key,
+    m2pack_verify,
     promote,
     publish,
     sign,
@@ -68,6 +72,18 @@ def _build_parser() -> argparse.ArgumentParser:
         sp = mod.add_parser(rsub)
         _add_common_flags(sp)
 
+    m2pack = sub.add_parser("m2pack", help="m2pack-secure archive commands.")
+    msub = m2pack.add_subparsers(dest="cmd", metavar="<command>")
+    msub.required = True
+    for mod in (
+        m2pack_build,
+        m2pack_verify,
+        m2pack_diff,
+        m2pack_export_runtime_key,
+    ):
+        sp = mod.add_parser(msub)
+        _add_common_flags(sp)
+
     return parser
 
 
@@ -80,6 +96,13 @@ _COMMAND_MAP: dict[tuple[str, str], tuple[str, CommandFn]] = {
     ("release", "promote"): ("release promote", promote.run),
     ("release", "verify-public"): ("release verify-public", verify_public.run),
     ("release", "publish"): ("release publish", publish.run),
+    ("m2pack", "build"): ("m2pack build", m2pack_build.run),
+    ("m2pack", "verify"): ("m2pack verify", m2pack_verify.run),
+    ("m2pack", "diff"): ("m2pack diff", m2pack_diff.run),
+    ("m2pack", "export-runtime-key"): (
+        "m2pack export-runtime-key",
+        m2pack_export_runtime_key.run,
+    ),
 }
 
 
diff --git a/src/metin_release/commands/__init__.py b/src/metin_release/commands/__init__.py
index 8cde4e5..aa9fe5f 100644
--- a/src/metin_release/commands/__init__.py
+++ b/src/metin_release/commands/__init__.py
@@ -4,6 +4,10 @@ from . import (
     build_manifest,
     diff_remote,
     inspect,
+    m2pack_build,
+    m2pack_diff,
+    m2pack_export_runtime_key,
+    m2pack_verify,
     promote,
     publish,
     sign,
@@ -15,6 +19,10 @@ __all__ = [
     "build_manifest",
     "diff_remote",
     "inspect",
+    "m2pack_build",
+    "m2pack_diff",
+    "m2pack_export_runtime_key",
+    "m2pack_verify",
     "promote",
     "publish",
     "sign",

From c4c65e2fe76d24ec4f7825d6f7406f3d4f7be2bd Mon Sep 17 00:00:00 2001
From: Jan Nedbal <jan.nedbal@apertia.cz>
Date: Tue, 14 Apr 2026 22:31:05 +0200
Subject: [PATCH 5/7] mcp: expose m2pack_* tools in the mcp server

Add four ToolSpec entries (m2pack_build, m2pack_verify, m2pack_diff,
m2pack_export_runtime_key) mirroring the CLI argparse signatures.
server.py auto-enumerates TOOL_SPECS so no wiring change needed.
---
 src/metin_release_mcp/tool_defs.py | 49 ++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)

diff --git a/src/metin_release_mcp/tool_defs.py b/src/metin_release_mcp/tool_defs.py
index aab9063..dbf88b4 100644
--- a/src/metin_release_mcp/tool_defs.py
+++ b/src/metin_release_mcp/tool_defs.py
@@ -64,6 +64,7 @@ class ToolSpec:
 # ---------------------------------------------------------------------------
 
 _RELEASE = ("release",)
+_M2PACK = ("m2pack",)
 
 
 TOOL_SPECS: tuple[ToolSpec, ...] = (
@@ -164,6 +165,54 @@ TOOL_SPECS: tuple[ToolSpec, ...] = (
             FieldSpec("dry_run_upload", "boolean", description="rsync --dry-run for upload + promote."),
         ),
     ),
+    ToolSpec(
+        name="m2pack_build",
+        subcommand=_M2PACK + ("build",),
+        description="Build a signed .m2p archive from a client asset directory via m2pack-secure.",
+        fields=(
+            FieldSpec("input", "path", required=True, description="Client asset source directory."),
+            FieldSpec("output", "path", required=True, description="Output .m2p archive path."),
+            FieldSpec("key", "path", required=True, description="Master content key file."),
+            FieldSpec(
+                "sign_secret_key",
+                "path",
+                required=True,
+                description="Ed25519 signing secret key file.",
+            ),
+            FieldSpec("key_id", "integer", description="Content key id (default 1)."),
+        ),
+    ),
+    ToolSpec(
+        name="m2pack_verify",
+        subcommand=_M2PACK + ("verify",),
+        description="Verify an .m2p archive's manifest signature and optionally full decrypt.",
+        fields=(
+            FieldSpec("archive", "path", required=True, description="Path to .m2p archive."),
+            FieldSpec("public_key", "path", description="Ed25519 public key file."),
+            FieldSpec("key", "path", description="Master content key file for full-decrypt verify."),
+        ),
+    ),
+    ToolSpec(
+        name="m2pack_diff",
+        subcommand=_M2PACK + ("diff",),
+        description="Diff two directories and/or .m2p archives (left vs right).",
+        fields=(
+            FieldSpec("left", "path", required=True, description="Left side: directory or .m2p archive."),
+            FieldSpec("right", "path", required=True, description="Right side: directory or .m2p archive."),
+        ),
+    ),
+    ToolSpec(
+        name="m2pack_export_runtime_key",
+        subcommand=_M2PACK + ("export-runtime-key",),
+        description="Export a launcher runtime-key payload (json or blob form) from master+public keys.",
+        fields=(
+            FieldSpec("key", "path", required=True, description="Master content key file."),
+            FieldSpec("public_key", "path", required=True, description="Ed25519 public key file."),
+            FieldSpec("output", "path", required=True, description="Output payload path."),
+            FieldSpec("key_id", "integer", description="Content key id (default 1)."),
+            FieldSpec("format", "string", description="Payload format: json or blob (default json)."),
+        ),
+    ),
 )
 
 

From 1201ec50d29555666926fe3b473b6049c36f5f0f Mon Sep 17 00:00:00 2001
From: Jan Nedbal <jan.nedbal@apertia.cz>
Date: Tue, 14 Apr 2026 22:31:11 +0200
Subject: [PATCH 6/7] tests: cover m2pack cli and mcp additions

Add discovery-helper tests (env var override, PATH fallback, missing
binary) and command tests that point M2PACK_BINARY at a Python stub
script echoing canned JSON per subcommand. Cover success paths,
non-zero exit, non-JSON output, JSON-array output, and missing binary.
Extend the MCP schema mirror test to cover all 12 tools and add
dispatch tests for the new m2pack_* argv translation.
---
 tests/mcp/test_tool_dispatch.py |  74 ++++++++
 tests/mcp/test_tool_schema.py   |  22 ++-
 tests/test_m2pack_binary.py     |  68 +++++++
 tests/test_m2pack_commands.py   | 307 ++++++++++++++++++++++++++++++++
 4 files changed, 466 insertions(+), 5 deletions(-)
 create mode 100644 tests/test_m2pack_binary.py
 create mode 100644 tests/test_m2pack_commands.py

diff --git a/tests/mcp/test_tool_dispatch.py b/tests/mcp/test_tool_dispatch.py
index b2a3d2d..6bd9dd7 100644
--- a/tests/mcp/test_tool_dispatch.py
+++ b/tests/mcp/test_tool_dispatch.py
@@ -199,6 +199,80 @@ def test_dispatch_invalid_input_returns_wrapper_error():
     assert envelope["error"]["code"] == "invalid_tool_input"
 
 
+def test_m2pack_build_translates_all_flags():
+    spec = TOOLS_BY_NAME["m2pack_build"]
+    argv = build_cli_args(
+        spec,
+        {
+            "input": "/src",
+            "output": "/out/a.m2p",
+            "key": "/ck",
+            "sign_secret_key": "/sk",
+            "key_id": 2,
+        },
+    )
+    assert argv[0:3] == ["m2pack", "build", "--json"]
+    assert "--input" in argv and argv[argv.index("--input") + 1] == "/src"
+    assert "--output" in argv and argv[argv.index("--output") + 1] == "/out/a.m2p"
+    assert "--sign-secret-key" in argv
+    assert argv[argv.index("--sign-secret-key") + 1] == "/sk"
+    assert "--key-id" in argv and argv[argv.index("--key-id") + 1] == "2"
+
+
+def test_m2pack_verify_omits_optional_keys():
+    spec = TOOLS_BY_NAME["m2pack_verify"]
+    argv = build_cli_args(spec, {"archive": "/a.m2p"})
+    assert argv == ["m2pack", "verify", "--json", "--archive", "/a.m2p"]
+
+
+def test_m2pack_diff_requires_both_sides():
+    from metin_release_mcp.errors import InvalidToolInputError
+
+    spec = TOOLS_BY_NAME["m2pack_diff"]
+    with pytest.raises(InvalidToolInputError):
+        build_cli_args(spec, {"left": "/L"})
+    argv = build_cli_args(spec, {"left": "/L", "right": "/R"})
+    assert argv == ["m2pack", "diff", "--json", "--left", "/L", "--right", "/R"]
+
+
+def test_m2pack_export_runtime_key_with_format():
+    spec = TOOLS_BY_NAME["m2pack_export_runtime_key"]
+    argv = build_cli_args(
+        spec,
+        {
+            "key": "/ck",
+            "public_key": "/pk",
+            "output": "/out",
+            "format": "blob",
+            "key_id": 4,
+        },
+    )
+    assert argv[0:3] == ["m2pack", "export-runtime-key", "--json"]
+    assert "--format" in argv and argv[argv.index("--format") + 1] == "blob"
+    assert "--key-id" in argv and argv[argv.index("--key-id") + 1] == "4"
+
+
+def test_dispatch_m2pack_build_through_fake_runner(stub_runner):
+    runner = stub_runner(
+        {"ok": True, "command": "m2pack build", "status": "built", "artifacts": {"archive_path": "/x.m2p"}}
+    )
+    envelope, _ = server.dispatch(
+        "m2pack_build",
+        {
+            "input": "/src",
+            "output": "/x.m2p",
+            "key": "/ck",
+            "sign_secret_key": "/sk",
+        },
+    )
+    assert envelope["ok"] is True
+    call = runner.calls[0]
+    assert "m2pack" in call and "build" in call
+    assert "--json" in call
+    assert "--input" in call and "/src" in call
+    assert "--sign-secret-key" in call and "/sk" in call
+
+
 def test_dispatch_unparseable_output_returns_wrapper_error(monkeypatch):
     def boom(argv_tail):
         from metin_release_mcp.errors import CliUnparseableOutputError
diff --git a/tests/mcp/test_tool_schema.py b/tests/mcp/test_tool_schema.py
index aa9ad8e..a5af77f 100644
--- a/tests/mcp/test_tool_schema.py
+++ b/tests/mcp/test_tool_schema.py
@@ -10,6 +10,10 @@ from metin_release.commands import (
     build_manifest,
     diff_remote,
     inspect,
+    m2pack_build,
+    m2pack_diff,
+    m2pack_export_runtime_key,
+    m2pack_verify,
     promote,
     publish,
     sign,
@@ -35,17 +39,21 @@ EXPECTED_TOOL_NAMES = {
     "release_promote",
     "release_verify_public",
     "release_publish",
+    "m2pack_build",
+    "m2pack_verify",
+    "m2pack_diff",
+    "m2pack_export_runtime_key",
 }
 
 
-def test_tool_catalogue_is_exactly_the_phase_one_set():
+def test_tool_catalogue_is_exactly_the_phase_one_plus_four_set():
     assert {t.name for t in TOOL_SPECS} == EXPECTED_TOOL_NAMES
-    assert len(TOOL_SPECS) == 8
+    assert len(TOOL_SPECS) == 12
 
 
-def test_every_tool_has_release_subcommand_and_description():
+def test_every_tool_has_known_group_and_description():
     for spec in TOOL_SPECS:
-        assert spec.subcommand[0] == "release"
+        assert spec.subcommand[0] in {"release", "m2pack"}
         assert spec.description.strip()
         schema = json_schema(spec)
         assert schema["type"] == "object"
@@ -82,6 +90,10 @@ _COMMAND_MODULES = {
     "release_promote": promote,
     "release_verify_public": verify_public,
     "release_publish": publish,
+    "m2pack_build": m2pack_build,
+    "m2pack_verify": m2pack_verify,
+    "m2pack_diff": m2pack_diff,
+    "m2pack_export_runtime_key": m2pack_export_runtime_key,
 }
 
 
@@ -121,7 +133,7 @@ def test_unknown_tool_rejected_by_dispatch():
 def test_unknown_tool_name_not_in_catalogue():
     assert "release_rollback" not in TOOLS_BY_NAME
     assert "erp_reserve" not in TOOLS_BY_NAME
-    assert "m2pack_build" not in TOOLS_BY_NAME
+    assert "launcher_publish" not in TOOLS_BY_NAME
 
 
 def test_build_cli_args_rejects_missing_required():
diff --git a/tests/test_m2pack_binary.py b/tests/test_m2pack_binary.py
new file mode 100644
index 0000000..0964662
--- /dev/null
+++ b/tests/test_m2pack_binary.py
@@ -0,0 +1,68 @@
+"""Tests for the m2pack binary discovery helper."""
+
+from __future__ import annotations
+
+import os
+import stat
+from pathlib import Path
+
+import pytest
+
+from metin_release.errors import ValidationError
+from metin_release.m2pack_binary import ENV_VAR, resolve_m2pack_binary
+
+
+def _make_stub(tmp_path: Path, name: str = "m2pack") -> Path:
+    stub = tmp_path / name
+    stub.write_text("#!/bin/sh\necho '{}'\n")
+    stub.chmod(stub.stat().st_mode | stat.S_IEXEC | stat.S_IXGRP | stat.S_IXOTH)
+    return stub
+
+
+def test_env_var_override_wins(tmp_path: Path, monkeypatch):
+    stub = _make_stub(tmp_path)
+    # Scrub PATH so shutil.which can't resolve m2pack
+    monkeypatch.setenv("PATH", "/nonexistent")
+    monkeypatch.setenv(ENV_VAR, str(stub))
+    resolved = resolve_m2pack_binary()
+    assert resolved == stub.resolve()
+
+
+def test_env_var_empty_falls_through_to_path(tmp_path: Path, monkeypatch):
+    stub = _make_stub(tmp_path)
+    monkeypatch.setenv(ENV_VAR, "   ")  # blank-ish
+    monkeypatch.setenv("PATH", str(tmp_path))
+    resolved = resolve_m2pack_binary()
+    assert resolved == stub.resolve()
+
+
+def test_env_var_pointing_nowhere_raises(tmp_path: Path, monkeypatch):
+    monkeypatch.setenv(ENV_VAR, str(tmp_path / "does-not-exist"))
+    monkeypatch.setenv("PATH", "/nonexistent")
+    with pytest.raises(ValidationError) as exc:
+        resolve_m2pack_binary()
+    assert exc.value.error_code == "m2pack_not_found"
+
+
+def test_path_fallback_used_when_env_unset(tmp_path: Path, monkeypatch):
+    stub = _make_stub(tmp_path)
+    monkeypatch.delenv(ENV_VAR, raising=False)
+    monkeypatch.setenv("PATH", str(tmp_path))
+    resolved = resolve_m2pack_binary()
+    assert resolved == stub.resolve()
+
+
+def test_missing_binary_raises_validation_error(monkeypatch):
+    monkeypatch.delenv(ENV_VAR, raising=False)
+    monkeypatch.setenv("PATH", "/nonexistent")
+    with pytest.raises(ValidationError) as exc:
+        resolve_m2pack_binary()
+    assert exc.value.error_code == "m2pack_not_found"
+    assert "M2PACK_BINARY" in str(exc.value)
+
+
+def test_custom_env_mapping_parameter(tmp_path: Path):
+    stub = _make_stub(tmp_path)
+    fake_env = {ENV_VAR: str(stub)}
+    resolved = resolve_m2pack_binary(env=fake_env)
+    assert resolved == stub.resolve()
diff --git a/tests/test_m2pack_commands.py b/tests/test_m2pack_commands.py
new file mode 100644
index 0000000..da6eb9d
--- /dev/null
+++ b/tests/test_m2pack_commands.py
@@ -0,0 +1,307 @@
+"""Tests for the m2pack wrapper subcommands.
+
+All tests use a stub binary — a small Python script that echoes a canned
+JSON envelope based on the subcommand name — pointed at via the
+``M2PACK_BINARY`` env var. The real m2pack-secure binary is never invoked.
+"""
+
+from __future__ import annotations
+
+import json
+import stat
+import sys
+from pathlib import Path
+
+import pytest
+
+from metin_release.cli import main as cli_main
+
+
+STUB_TEMPLATE = r"""#!{python}
+import json
+import sys
+
+argv = sys.argv[1:]
+sub = argv[0] if argv else "unknown"
+MODE = {mode!r}
+
+if MODE == "fail":
+    sys.stderr.write("boom\n")
+    sys.exit(2)
+if MODE == "nonjson":
+    sys.stdout.write("not json at all\n")
+    sys.exit(0)
+if MODE == "notobject":
+    sys.stdout.write(json.dumps([1, 2, 3]) + "\n")
+    sys.exit(0)
+
+# mode == "ok": echo a canned envelope per subcommand
+if sub == "build":
+    env = {{"ok": True, "command": "build", "stats": {{"files": 3, "bytes": 12345}}}}
+elif sub == "verify":
+    env = {{"ok": True, "command": "verify", "signature": "valid"}}
+elif sub == "diff":
+    env = {{"ok": True, "command": "diff", "added": ["a"], "removed": [], "changed": ["b", "c"], "unchanged": 7}}
+elif sub == "export-runtime-key":
+    env = {{"ok": True, "command": "export-runtime-key", "key_id": 1, "format": "json"}}
+else:
+    env = {{"ok": True, "command": sub}}
+
+# Record argv so the test can assert translation
+import os
+log = os.environ.get("M2PACK_STUB_LOG")
+if log:
+    with open(log, "a") as fh:
+        fh.write(json.dumps(argv) + "\n")
+
+sys.stdout.write(json.dumps(env) + "\n")
+sys.exit(0)
+"""
+
+
+def _install_stub(tmp_path: Path, monkeypatch, mode: str = "ok") -> tuple[Path, Path]:
+    stub = tmp_path / "m2pack_stub.py"
+    stub.write_text(STUB_TEMPLATE.format(python=sys.executable, mode=mode))
+    stub.chmod(stub.stat().st_mode | stat.S_IEXEC | stat.S_IXGRP | stat.S_IXOTH)
+    log = tmp_path / "stub.log"
+    monkeypatch.setenv("M2PACK_BINARY", str(stub))
+    monkeypatch.setenv("M2PACK_STUB_LOG", str(log))
+    return stub, log
+
+
+def _run_cli(argv: list[str], capsys) -> dict:
+    rc = cli_main(argv)
+    out = capsys.readouterr().out
+    envelope = json.loads(out)
+    return {"rc": rc, "env": envelope}
+
+
+def _read_stub_call(log: Path) -> list[str]:
+    lines = [ln for ln in log.read_text().splitlines() if ln.strip()]
+    assert lines, "stub was never invoked"
+    return json.loads(lines[-1])
+
+
+# ---------------------------------------------------------------------------
+# Success paths
+# ---------------------------------------------------------------------------
+
+
+def test_build_success(tmp_path, monkeypatch, capsys):
+    _, log = _install_stub(tmp_path, monkeypatch)
+    (tmp_path / "in").mkdir()
+    key = tmp_path / "k.hex"
+    key.write_text("ff")
+    sk = tmp_path / "sk.hex"
+    sk.write_text("aa")
+    out = tmp_path / "out.m2p"
+
+    r = _run_cli(
+        [
+            "--json",
+            "m2pack",
+            "build",
+            "--input", str(tmp_path / "in"),
+            "--output", str(out),
+            "--key", str(key),
+            "--sign-secret-key", str(sk),
+            "--key-id", "7",
+        ],
+        capsys,
+    )
+    assert r["rc"] == 0
+    assert r["env"]["ok"] is True
+    assert r["env"]["command"] == "m2pack build"
+    assert r["env"]["status"] == "built"
+    assert r["env"]["artifacts"]["archive_path"] == str(out)
+    assert r["env"]["m2pack"]["stats"]["files"] == 3
+
+    call = _read_stub_call(log)
+    assert call[0] == "build"
+    assert "--input" in call and str(tmp_path / "in") in call
+    assert "--output" in call and str(out) in call
+    assert "--key" in call and str(key) in call
+    assert "--sign-secret-key" in call and str(sk) in call
+    assert "--key-id" in call and "7" in call
+    assert "--json" in call
+
+
+def test_build_omits_optional_key_id(tmp_path, monkeypatch, capsys):
+    _, log = _install_stub(tmp_path, monkeypatch)
+    (tmp_path / "in").mkdir()
+    (tmp_path / "k").write_text("a")
+    (tmp_path / "sk").write_text("b")
+    _run_cli(
+        [
+            "--json", "m2pack", "build",
+            "--input", str(tmp_path / "in"),
+            "--output", str(tmp_path / "o.m2p"),
+            "--key", str(tmp_path / "k"),
+            "--sign-secret-key", str(tmp_path / "sk"),
+        ],
+        capsys,
+    )
+    call = _read_stub_call(log)
+    assert "--key-id" not in call
+
+
+def test_verify_success_without_keys(tmp_path, monkeypatch, capsys):
+    _, log = _install_stub(tmp_path, monkeypatch)
+    archive = tmp_path / "a.m2p"
+    archive.write_bytes(b"x")
+    r = _run_cli(
+        ["--json", "m2pack", "verify", "--archive", str(archive)], capsys
+    )
+    assert r["rc"] == 0
+    assert r["env"]["status"] == "verified"
+    assert r["env"]["m2pack"]["signature"] == "valid"
+    call = _read_stub_call(log)
+    assert call[0] == "verify"
+    assert "--public-key" not in call
+    assert "--key" not in call
+
+
+def test_verify_with_public_and_content_keys(tmp_path, monkeypatch, capsys):
+    _, log = _install_stub(tmp_path, monkeypatch)
+    archive = tmp_path / "a.m2p"
+    archive.write_bytes(b"x")
+    pk = tmp_path / "pub"
+    pk.write_text("ff")
+    ck = tmp_path / "ck"
+    ck.write_text("aa")
+    _run_cli(
+        [
+            "--json", "m2pack", "verify",
+            "--archive", str(archive),
+            "--public-key", str(pk),
+            "--key", str(ck),
+        ],
+        capsys,
+    )
+    call = _read_stub_call(log)
+    assert "--public-key" in call and str(pk) in call
+    assert "--key" in call and str(ck) in call
+
+
+def test_diff_success_promotes_counts(tmp_path, monkeypatch, capsys):
+    _, log = _install_stub(tmp_path, monkeypatch)
+    left = tmp_path / "L"
+    left.mkdir()
+    right = tmp_path / "R.m2p"
+    right.write_bytes(b"x")
+    r = _run_cli(
+        [
+            "--json", "m2pack", "diff",
+            "--left", str(left),
+            "--right", str(right),
+        ],
+        capsys,
+    )
+    assert r["rc"] == 0
+    assert r["env"]["status"] == "diffed"
+    stats = r["env"]["stats"]
+    assert stats["added_count"] == 1
+    assert stats["removed_count"] == 0
+    assert stats["changed_count"] == 2
+    assert stats["unchanged_count"] == 7
+    call = _read_stub_call(log)
+    assert call[0] == "diff"
+
+
+def test_export_runtime_key_success(tmp_path, monkeypatch, capsys):
+    _, log = _install_stub(tmp_path, monkeypatch)
+    key = tmp_path / "ck"
+    key.write_text("aa")
+    pk = tmp_path / "pk"
+    pk.write_text("ff")
+    out = tmp_path / "runtime.json"
+    r = _run_cli(
+        [
+            "--json", "m2pack", "export-runtime-key",
+            "--key", str(key),
+            "--public-key", str(pk),
+            "--output", str(out),
+            "--key-id", "3",
+            "--format", "blob",
+        ],
+        capsys,
+    )
+    assert r["rc"] == 0
+    assert r["env"]["status"] == "exported"
+    assert r["env"]["artifacts"]["runtime_key_path"] == str(out)
+    call = _read_stub_call(log)
+    assert call[0] == "export-runtime-key"
+    assert "--format" in call and "blob" in call
+    assert "--key-id" in call and "3" in call
+
+
+def test_export_runtime_key_rejects_bad_format(tmp_path, monkeypatch, capsys):
+    _install_stub(tmp_path, monkeypatch)
+    with pytest.raises(SystemExit):
+        cli_main(
+            [
+                "--json", "m2pack", "export-runtime-key",
+                "--key", str(tmp_path / "k"),
+                "--public-key", str(tmp_path / "p"),
+                "--output", str(tmp_path / "o"),
+                "--format", "yaml",
+            ]
+        )
+
+
+# ---------------------------------------------------------------------------
+# Error paths
+# ---------------------------------------------------------------------------
+
+
+def test_nonzero_exit_maps_to_subprocess_failed(tmp_path, monkeypatch, capsys):
+    _install_stub(tmp_path, monkeypatch, mode="fail")
+    (tmp_path / "in").mkdir()
+    (tmp_path / "k").write_text("a")
+    (tmp_path / "sk").write_text("b")
+    rc = cli_main(
+        [
+            "--json", "m2pack", "build",
+            "--input", str(tmp_path / "in"),
+            "--output", str(tmp_path / "o.m2p"),
+            "--key", str(tmp_path / "k"),
+            "--sign-secret-key", str(tmp_path / "sk"),
+        ],
+    )
+    assert rc == 1
+    env = json.loads(capsys.readouterr().out)
+    assert env["ok"] is False
+    assert env["error"]["code"] == "m2pack_failed"
+
+
+def test_nonjson_output_maps_to_invalid_json(tmp_path, monkeypatch, capsys):
+    _install_stub(tmp_path, monkeypatch, mode="nonjson")
+    archive = tmp_path / "a.m2p"
+    archive.write_bytes(b"x")
+    rc = cli_main(["--json", "m2pack", "verify", "--archive", str(archive)])
+    assert rc == 1
+    env = json.loads(capsys.readouterr().out)
+    assert env["ok"] is False
+    assert env["error"]["code"] == "m2pack_invalid_json"
+
+
+def test_json_array_output_maps_to_invalid_json(tmp_path, monkeypatch, capsys):
+    _install_stub(tmp_path, monkeypatch, mode="notobject")
+    archive = tmp_path / "a.m2p"
+    archive.write_bytes(b"x")
+    rc = cli_main(["--json", "m2pack", "verify", "--archive", str(archive)])
+    assert rc == 1
+    env = json.loads(capsys.readouterr().out)
+    assert env["error"]["code"] == "m2pack_invalid_json"
+
+
+def test_missing_binary_raises_validation_error(tmp_path, monkeypatch, capsys):
+    monkeypatch.delenv("M2PACK_BINARY", raising=False)
+    monkeypatch.setenv("PATH", "/nonexistent")
+    archive = tmp_path / "a.m2p"
+    archive.write_bytes(b"x")
+    rc = cli_main(["--json", "m2pack", "verify", "--archive", str(archive)])
+    assert rc == 1
+    env = json.loads(capsys.readouterr().out)
+    assert env["ok"] is False
+    assert env["error"]["code"] == "m2pack_not_found"

From 22f67a0589422871e5efd25032800d793da050ad Mon Sep 17 00:00:00 2001
From: Jan Nedbal <jan.nedbal@apertia.cz>
Date: Tue, 14 Apr 2026 22:31:16 +0200
Subject: [PATCH 7/7] docs: document m2pack subcommands

Add a Phase 4 'm2pack commands' section to docs/cli.md with each
subcommand's flags and a pointer at the m2pack-secure repo for
installation. Update README.md with a short m2pack paragraph and
append the Phase 4 entry to the Unreleased CHANGELOG section.
---
 CHANGELOG.md |  3 +++
 README.md    | 14 ++++++++++
 docs/cli.md  | 75 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 3 files changed, 91 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4db8281..ad66862 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,9 @@ contract.
 
 ### Added
 
+- `metin-release m2pack <build|verify|diff|export-runtime-key>` subcommands that wrap the m2pack-secure binary.
+- `m2pack_build`, `m2pack_verify`, `m2pack_diff`, `m2pack_export_runtime_key` MCP tools mirroring the CLI surface.
+- `src/metin_release/m2pack_binary.py` binary-discovery helper using `M2PACK_BINARY` env var or `PATH`.
 - `metin_release_mcp` package and `metin-release-mcp` console script — a
   thin Model Context Protocol stdio server that wraps the Phase 1
   `release …` subcommands as eight MCP tools (`release_inspect`,
diff --git a/README.md b/README.md
index e40c6c9..0499273 100644
--- a/README.md
+++ b/README.md
@@ -32,6 +32,20 @@ Add `--json` to get a machine-parseable envelope on stdout. Exit codes:
 
 See `docs/cli.md` for the full command reference.
 
+## m2pack commands
+
+Phase 4 adds a `metin-release m2pack …` command group that wraps the
+[`m2pack-secure`](https://gitea.jakubkadlec.dev/metin-server/m2pack-secure)
+binary for building, verifying, diffing, and runtime-key-exporting
+signed `.m2p` archives. The binary is not bundled — build it from the
+m2pack-secure repo and either put it on `PATH` or set `M2PACK_BINARY`
+to an absolute path.
+
+```
+metin-release m2pack build --input ... --output a.m2p --key ck --sign-secret-key sk
+metin-release m2pack verify --archive a.m2p --public-key pk
+```
+
 ## MCP server
 
 The `metin-release-mcp` console script (Phase 3) exposes each Phase 1
diff --git a/docs/cli.md b/docs/cli.md
index 42f2f00..e3a5ebb 100644
--- a/docs/cli.md
+++ b/docs/cli.md
@@ -1,6 +1,7 @@
 # metin-release — CLI reference
 
-Phase 1 commands. All subcommands share the top-level flags.
+Phase 1 `release …` commands and Phase 4 `m2pack …` commands. All
+subcommands share the top-level flags.
 
 ## Top-level flags
 
@@ -145,3 +146,75 @@ metin-release release publish \
     [--created-at ...] [--sample-blobs N] \
     [--yes] [--force] [--dry-run-upload]
 ```
+
+## m2pack commands
+
+Phase 4 subcommands wrap the `m2pack-secure` binary and translate its
+JSON envelopes into the standard metin-release result envelope. The
+binary is **not** shipped with this CLI — build it from
+[`metin-server/m2pack-secure`](https://gitea.jakubkadlec.dev/metin-server/m2pack-secure)
+and either put it on `PATH` or point at it via the `M2PACK_BINARY`
+environment variable.
+
+All m2pack commands pass through `--json` to the real tool, so the
+raw m2pack envelope is always available under `data.m2pack`. When
+m2pack exits non-zero or emits non-JSON output the wrapper raises a
+subprocess error with `m2pack_failed` / `m2pack_invalid_json` /
+`m2pack_empty_output` error codes.
+
+### `m2pack build`
+
+Build a signed `.m2p` archive from a client asset directory.
+
+```
+metin-release m2pack build \
+    --input /path/to/client-assets \
+    --output /path/to/out.m2p \
+    --key /path/to/content.key \
+    --sign-secret-key /path/to/signing.sk \
+    [--key-id N]
+```
+
+### `m2pack verify`
+
+Verify an `.m2p` archive's signature (and optionally full-decrypt it).
+
+```
+metin-release m2pack verify \
+    --archive /path/to/a.m2p \
+    [--public-key /path/to/signing.pub] \
+    [--key /path/to/content.key]
+```
+
+Passing `--key` enables full-decrypt verification; omitting it only
+checks manifest structure and signature.
+
+### `m2pack diff`
+
+Diff two directories and/or `.m2p` archives. Either side can be a
+directory or an archive; m2pack figures it out.
+
+```
+metin-release m2pack diff --left /old --right /new.m2p
+```
+
+The wrapper promotes m2pack's added/removed/changed/unchanged counts
+into `data.stats` when available.
+
+### `m2pack export-runtime-key`
+
+Export a launcher runtime-key payload (json or raw blob) from a master
+content key + signing public key. Used to seed the launcher's bundled
+runtime-key file during release workflows.
+
+```
+metin-release m2pack export-runtime-key \
+    --key /path/to/content.key \
+    --public-key /path/to/signing.pub \
+    --output /path/to/runtime-key.json \
+    [--key-id N] [--format json|blob]
+```
+
+See `docs/key-rotation.md` in `m2pack-secure` for when to re-export
+runtime keys.
+