re-dotnet-patch

MCP server for structured patching of Mono / .NET assemblies.

Status

v2.8.0 — SKELETON. Tool contracts are final and pinned by tests (tests/test_re_dotnet_patch.py). The actual round-trip patcher backend (dnlib / Mono.Cecil / pythonnet) lands in v2.8.1.

Every mutating tool currently returns a structured {status: "not_implemented", reason, remediation, schema_for_replay} dict, so:

1. Downstream skills can target the tool names today.
2. Callers can serialize the operation as a patch descriptor for later replay once v2.8.1 lands.
3. The CHANGELOG entry for v2.8.0 can advertise the new server even though the backend is deferred.

Tools

Tool	Status	What it does
check_dnlib	WARN (stub)	Probe for the future backend
nop_method	not_implemented	Replace a method body with a NOP-sled (return default)
replace_method_body	not_implemented	Replace a method body with caller-supplied IL bytes
replace_string_ldstr	not_implemented	Replace a specific ldstr operand within a method body
patch_assembly	not_implemented	Apply a list of operations atomically
rollback_patch	delegate	Delegate to re-patch.restore_original

Why a new server (not a helper in re-patch)?

re-patch is byte-splice only, pure-stdlib + mcp/pydantic. Adding a heavy dnlib / Mono.Cecil dep would bloat re-patch's surface for callers that only need a byte-splice. Per the v2.8.0 plan (approved 2026-06-07, LO decision), the Mono dnlib patcher ships as a new server to keep the dep boundary clean. Costs 1 server-count entry in .mcp.json (30 → 31).

What this server does NOT do

• It does NOT NOP a method body today. v2.8.1 will. For v2.8.0, decompile the assembly with re-dotnet.decompile_type, edit the C# source by hand to stub the target method, then recompile.
• It does NOT touch native / non-.NET binaries. Use re-patch for byte-splice; use re-vm-reverse for VM-protected native code.
• It does NOT restore originals — call re-patch.restore_original directly. The rollback_patch tool delegates by-documentation.

Closing CD-3

The r03-stress run identified MonoLauncher::PASystemInfoScanner.MainWindow as the Mono Steam-gate target (see See the RE-AI output directory. for the full decompile). Once v2.8.1 lands the dnlib backend, nop_method("PASystemInfoScanner.MainWindow::GetSteamRegistryKey") will close CD-3 as a HIGH-confidence patch (currently DOC-ONLY).

License

MIT.