dnSpy MCP Server

A Model Context Protocol (MCP) server embedded in dnSpy that exposes full .NET assembly analysis, editing, debugging, memory-dump, and deobfuscation capabilities to any MCP-compatible AI assistant.

Version: 1.6.0 | Tools: 95 | Status: ✅ 0 errors, 0 warnings | Targets: .NET 4.8 + .NET 10.0-windows

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Table of Contents

1. Features
2. Build & Install
3. Client Configuration
4. Tool Reference
   • Assembly Tools
   • Type & Member Tools
   • Method & Decompilation Tools
   • IL Tools
   • Analysis & Cross-Reference Tools
   • Edit Tools
   • Embedded Resource Tools
   • Debug Tools
   • Memory Dump & PE Tools
   • Static PE Analysis
   • Deobfuscation Tools
   • Window / Dialog Tools
   • Utility
5. Pattern Syntax
6. Pagination
7. Usage Examples
8. Architecture
9. Project Structure
10. Configuration
11. Troubleshooting

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Features

Category	Capabilities
Assembly	List loaded assemblies, namespaces, type counts, P/Invoke imports
Types	Inspect types, fields, properties, events, nested types, attributes, inheritance
Decompilation	Decompile entire types or individual methods to C#
IL	View IL instructions, raw bytes, local variables, exception handlers
Analysis	Find callers/users, trace field reads/writes, call graphs, dead code, cross-assembly dependencies
Edit	Rename members, change access modifiers, edit metadata, patch methods, inject types, save to disk
Resources	List, read, add, remove embedded resources (ManifestResource table); extract Costura.Fody-embedded assemblies
Debug	Manage breakpoints (with conditions), launch/attach processes, pause/resume/stop sessions, single-step (over/into/out), inspect call stacks, read locals, evaluate expressions
Memory Dump	List runtime modules, dump .NET or native modules from memory, read/write process memory, extract PE sections
Static PE Analysis	Scan raw PE bytes for strings; all-in-one ConfuserEx unpacker
Deobfuscation	de4dot integration: detect obfuscator, rename mangled symbols, decrypt strings. Both in-process (deobfuscate_assembly) and external process (run_de4dot) modes available in all builds
Window / Dialog	List active dialog/message-box windows (Win32 #32770 + WPF) in the dnSpy process; dismiss them by clicking any button by name (supports EN and ES)
Search	Glob and regex search across all loaded assemblies

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Build & Install

Prerequisites

Requirement	Version
.NET SDK	10.0+ (for net10.0-windows target)
.NET Framework SDK	4.8 (for net48 target)
OS	Windows (WPF dependency)
dnSpy	dnSpyEx (this repo)

de4dot integration — de4dot libraries are bundled in libs/de4dot/ (net48) and libs/de4dot-net8/ (net8/net10). No external dependencies required; all deobfuscation tools are available in both build targets.

Clone & Restore

git clone https://github.com/dnSpyEx/dnSpy --recursive
cd dnSpy

Build commands

# Build only the MCP Server extension (Debug)
dotnet build Extensions/dnSpy.MCP.Server/dnSpy.MCP.Server.csproj -c Debug

# Build only the MCP Server extension (Release)
dotnet build Extensions/dnSpy.MCP.Server/dnSpy.MCP.Server.csproj -c Release

# Build the full dnSpy solution (both targets)
dotnet build dnSpy.sln -c Debug

# Build for a specific target framework only
dotnet build Extensions/dnSpy.MCP.Server/dnSpy.MCP.Server.csproj -c Release -f net10.0-windows
dotnet build Extensions/dnSpy.MCP.Server/dnSpy.MCP.Server.csproj -c Release -f net48

# Restore NuGet packages without building
dotnet restore Extensions/dnSpy.MCP.Server/dnSpy.MCP.Server.csproj

# Clean build artifacts
dotnet clean Extensions/dnSpy.MCP.Server/dnSpy.MCP.Server.csproj

Output locations

Target	Output path
.NET 10.0-windows	dnSpy/dnSpy/bin/Release/net10.0-windows/dnSpy.MCP.Server.x.dll
.NET Framework 4.8	dnSpy/dnSpy/bin/Release/net48/dnSpy.MCP.Server.x.dll

The MCP Server DLL is output directly into dnSpy's bin directory so it loads automatically when you start dnSpy.

Verify the build

# Check for errors (expects "Compilación correcta" or "Build succeeded")
dotnet build Extensions/dnSpy.MCP.Server/dnSpy.MCP.Server.csproj -c Release --nologo 2>&1 | tail -5

Runtime

1. Start dnSpy — the MCP server starts automatically on http://localhost:3100
2. Verify it is running:

   curl http://localhost:3100/health
   curl -N --max-time 3 http://localhost:3100/sse   # should print event: endpoint
   

3. Configure your MCP client (see next section)

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Client Configuration

The server implements the MCP SSE transport (spec version 2024-11-05). On connect the server sends an event: endpoint with the per-session POST URL; responses are pushed back over the SSE stream.

Claude Code (CLI)

claude mcp add dnspy --transport sse http://localhost:3100/sse

Claude Desktop

{
  "mcpServers": {
    "dnspy": {
      "type": "sse",
      "url": "http://localhost:3100/sse"
    }
  }
}

Or

claude mcp add dnspy --transport sse http://localhost:3100/sse

OpenCode

{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "dnspy": {
      "type": "remote",
      "url": "http://localhost:3100/sse",
      "enabled": true
    }
  }
}

Kilo Code / Roo Code

{
  "mcpServers": {
    "dnspy-mcp": {
      "type": "sse",
      "url": "http://localhost:3100/sse",
      "alwaysAllow": [
        "list_assemblies", "list_tools", "search_types",
        "get_type_info", "list_methods_in_type"
      ],
      "disabled": false
    }
  }
}

Codex CLI

{
  "mcpServers": {
    "dnspy": {
      "type": "sse",
      "url": "http://localhost:3100/sse",
      "timeout": 30
    }
  }
}

Gemini CLI

mcpServers:
  dnspy:
    type: sse
    url: http://localhost:3100/sse

SSE endpoints: GET /sse (or /events, /) opens the event stream. The server immediately sends event: endpoint\ndata: http://localhost:3100/message?sessionId=<id>. The client then POSTs JSON-RPC requests to that URL and receives responses as event: message SSE events. POST / still accepts direct JSON-RPC for curl/scripting use.

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Tool Reference

All tools are called over MCP as tools/call with a JSON arguments object. Parameters marked required must always be provided; all others are optional.

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Assembly Tools

Tools for listing and inspecting .NET assemblies loaded in dnSpy.

Tool	Description	Required params	Optional params
list_assemblies	List every assembly currently open in dnSpy, with version, culture, and public key token	—	—
get_assembly_info	Detailed info for one assembly: modules, namespaces, type count	assembly_name	cursor
list_types	List types in an assembly, with class/interface/enum flags. Supports glob and regex via name_pattern	assembly_name	namespace, name_pattern, cursor
list_native_modules	List native DLLs imported via [DllImport], grouped by DLL name with the managed methods that use them	assembly_name	—
load_assembly	Load a .NET assembly into dnSpy from a file on disk or from a running process by PID. Supports both normal PE layout and raw memory-layout dumps	—	file_path, memory_layout, pid, module_name
select_assembly	Select an assembly in the dnSpy document tree and open it in the active tab; changes the current assembly context for subsequent operations	assembly_name	file_path
close_assembly	Close (remove) a specific assembly from dnSpy	assembly_name	file_path
close_all_assemblies	Close all assemblies currently loaded in dnSpy, clearing the document tree	—	—

Parameter details

Parameter	Type	Description
assembly_name	string	Short assembly name as shown in dnSpy (e.g. UnityEngine.CoreModule)
namespace	string	Exact namespace filter (e.g. System.Collections.Generic)
name_pattern	string	Glob or regex filter on type name — see Pattern Syntax
cursor	string	Opaque base-64 pagination cursor from nextCursor in a previous response
file_path	string	(load_assembly) Absolute path to a .NET assembly or memory dump
memory_layout	boolean	(load_assembly) When true, treat the file as raw memory-layout (VAs, not file offsets). Default false
pid	integer	(load_assembly) PID of a running .NET process to dump from. Requires active debug session.
module_name	string	(load_assembly) Module name/filename to pick when using pid. Defaults to first EXE module.
file_path	string	(select_assembly, close_assembly) Absolute path (FilePath from list_assemblies) to disambiguate when multiple assemblies share the same short name

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Type & Member Tools

Tools for inspecting the internals of a specific type.

Tool	Description	Required params	Optional params
get_type_info	Full type overview: visibility, base type, interfaces, fields, properties, methods (paginated)	assembly_name, type_full_name	cursor
search_types	Search for types by name across all loaded assemblies	query	cursor
get_type_fields	List fields matching a name pattern, with type, visibility, and readonly/const flags	assembly_name, type_full_name, pattern	cursor
get_type_property	Full detail for a single property: getter/setter signatures, attributes	assembly_name, type_full_name, property_name	—
list_properties_in_type	Summary list of all properties with read/write flags	assembly_name, type_full_name	cursor
list_events_in_type	All events with add/remove method info	assembly_name, type_full_name	—
list_nested_types	All nested types recursively (full name, visibility, kind)	assembly_name, type_full_name	—
get_custom_attributes	Custom attributes on the type or on one of its members	assembly_name, type_full_name	member_name, member_kind
analyze_type_inheritance	Full inheritance chain (base classes + interfaces)	assembly_name, type_full_name	—
find_path_to_type	BFS traversal of property/field references to find how one type reaches another	assembly_name, from_type, to_type	max_depth

Parameter details

Parameter	Type	Description
type_full_name	string	Fully-qualified type name (e.g. MyNamespace.MyClass)
query	string	Substring, glob, or regex matched against FullName
pattern	string	Glob or regex for field name matching; use * to list all
property_name	string	Exact property name (case-insensitive)
member_name	string	Member name for attribute lookup (omit to get type-level attributes)
member_kind	string	Disambiguates overloaded names: method, field, property, or event
from_type	string	Full name of starting type for BFS path search
to_type	string	Name or substring of the target type
max_depth	integer	BFS depth limit (default 5)

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Method & Decompilation Tools

Tools for decompiling code and exploring method metadata.

Tool	Description	Required params	Optional params
decompile_type	Decompile an entire type (class/struct/interface/enum) to C#	assembly_name, type_full_name	—
decompile_method	Decompile a single method to C#	assembly_name, type_full_name, method_name	—
list_methods_in_type	List methods with return type, visibility, static, virtual, parameter count. Filter by visibility or name pattern	assembly_name, type_full_name	visibility, name_pattern, cursor
get_method_signature	Full signature for one method: parameters, return type, generic constraints	assembly_name, type_full_name, method_name	—

Parameter details

Parameter	Type	Description
method_name	string	Method name (first match when overloads exist; use get_method_signature to disambiguate)
visibility	string	Filter: public, private, protected, or internal
name_pattern	string	Glob or regex on method name (e.g. Get*, ^On[A-Z], Async$)

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IL Tools

Low-level IL inspection for a method body.

Tool	Description	Required params	Optional params
get_method_il	IL instruction listing with offsets, opcodes, operands, and local variable table	assembly_name, type_full_name, method_name	—
get_method_il_bytes	Raw IL bytes as a hex string and Base64	assembly_name, type_full_name, method_name	—
get_method_exception_handlers	try/catch/finally/fault region table (offsets and handler type)	assembly_name, type_full_name, method_name	—
dump_cordbg_il	For each MethodDef in the paused module, reads ICorDebugFunction.ILCode.Address and ILCode.Size via the CorDebug COM API (through reflection). Reports whether IL addresses fall inside the PE image (encrypted stubs) or outside (JIT hook buffers). Useful for ConfuserEx JIT-hook analysis. Requires an active paused debug session	—	module_name, output_path, max_methods, include_bytes

Parameter details (dump_cordbg_il)

Parameter	Type	Description
module_name	string	Module name or filename filter (default: first EXE module)
output_path	string	Optional path to save full JSON results to disk
max_methods	integer	Max number of MethodDef tokens to scan (default 10000)
include_bytes	boolean	When true, include Base64-encoded IL bytes for each method (default false)

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Analysis & Cross-Reference Tools

Call-graph, usage, and dependency analysis across all loaded assemblies.

Tool	Description	Required params	Optional params
find_who_calls_method	Find every method whose IL contains a call/callvirt to the target	assembly_name, type_full_name, method_name	—
find_who_uses_type	Find all types, methods, and fields that reference a type (base class, interface, field type, parameter, return type)	assembly_name, type_full_name	—
find_who_reads_field	Find all methods that read a field via ldfld/ldsfld IL instructions	assembly_name, type_full_name, field_name	—
find_who_writes_field	Find all methods that write to a field via stfld/stsfld IL instructions	assembly_name, type_full_name, field_name	—
analyze_call_graph	Build a recursive call graph for a method, showing all methods it calls down to a configurable depth	assembly_name, type_full_name, method_name	max_depth
find_dependency_chain	Find all dependency paths between two types via BFS over base types, interfaces, fields, parameters, and return types	assembly_name, from_type, to_type	max_depth
analyze_cross_assembly_dependencies	Compute a dependency matrix for all loaded assemblies, showing which assemblies each depends on	—	—
find_dead_code	Identify methods and types never called or referenced (static approximation; virtual dispatch and reflection are not tracked)	assembly_name	—

Parameter details

Parameter	Type	Description
field_name	string	Exact field name to search for read/write access
max_depth	integer	Recursion depth limit for call-graph or BFS traversal (default 5)

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Edit Tools

In-memory metadata editing. Changes are applied immediately to dnlib's in-memory model and persist until save_assembly is called or dnSpy is closed without saving.

Tool	Description	Required params	Optional params
change_member_visibility	Change the access modifier of a type or one of its members	assembly_name, type_full_name, member_kind, new_visibility	member_name
rename_member	Rename a type or one of its members	assembly_name, type_full_name, member_kind, old_name, new_name	—
save_assembly	Write the (possibly modified) assembly to disk using dnlib's ModuleWriter	assembly_name	output_path
get_assembly_metadata	Read assembly-level metadata: name, version, culture, public key, flags, hash algorithm, module count, custom attributes	assembly_name	—
edit_assembly_metadata	Edit assembly-level metadata fields: name, version, culture, or hash algorithm	assembly_name	name, version, culture, hash_algorithm
set_assembly_flags	Set or clear an individual assembly attribute flag (e.g. PublicKey, Retargetable, processor architecture)	assembly_name, flag_name, value	—
list_assembly_references	List all assembly references (AssemblyRef table entries) in the manifest module	assembly_name	—
add_assembly_reference	Add an assembly reference by loading a DLL from disk. Creates a TypeForwarder to anchor the reference	assembly_name, dll_path	—
remove_assembly_reference	Remove an AssemblyRef entry and all TypeForwarder entries that target it. Returns a warning if TypeRefs in code still use the reference	assembly_name, reference_name	—
inject_type_from_dll	Deep-clone a type (fields, methods with IL, properties, events) from an external DLL into the target assembly	assembly_name, dll_path, type_full_name	—
list_pinvoke_methods	List all P/Invoke (DllImport) declarations in a type: managed name, token, DLL name, native function name	assembly_name, type_full_name	—
patch_method_to_ret	Replace a method's IL body with a minimal return stub (nop + ret) to neutralize it. Works on P/Invoke methods too (converts to managed stub)	assembly_name, type_full_name, method_name	—

Parameter details

Parameter	Type	Values / Description
member_kind	string	type, method, field, property, or event
new_visibility	string	public, private, protected, internal, protected_internal, private_protected
old_name	string	Current member name
new_name	string	Desired new name
output_path	string	Absolute path for output file. Defaults to the original file location.
flag_name	string	Assembly flag to toggle (e.g. PublicKey, Retargetable, PA_MSIL, PA_x86, PA_AMD64)
value	boolean	true to set the flag, false to clear it
dll_path	string	Absolute path to the source DLL

Note: rename_member changes only the metadata name. It does not update call sites, string literals, or XML docs.

Note: patch_method_to_ret is ideal for disabling anti-debug, anti-tamper, or license-check routines before saving and re-analyzing.

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Embedded Resource Tools

Read, write, and extract entries from the ManifestResource table. All write operations are in-memory until save_assembly is called.

Tool	Description	Required params	Optional params
list_resources	List all ManifestResource entries: name, kind (Embedded/Linked/AssemblyLinked), size, visibility, and whether it looks like a Costura.Fody-embedded assembly	assembly_name	—
get_resource	Extract an embedded resource as Base64 (up to 4 MB inline) and/or save to disk	assembly_name, resource_name	output_path, skip_base64
add_resource	Embed a file from disk as a new EmbeddedResource in the assembly	assembly_name, resource_name, file_path	is_public
remove_resource	Delete a ManifestResource entry by name	assembly_name, resource_name	—
extract_costura	Detect and extract Costura.Fody-embedded assemblies (costura.*.dll.compressed resources). Decompresses gzip automatically. Useful for analysing assemblies packed with Costura	assembly_name, output_directory	decompress

Parameter details

Parameter	Type	Description
resource_name	string	Exact resource name (use list_resources to find it)
output_path	string	(get_resource) Absolute path to write raw resource bytes
skip_base64	boolean	(get_resource) Omit Base64 from response; useful when saving large resources to disk (default false)
is_public	boolean	(add_resource) Resource visibility — true = Public (default), false = Private
output_directory	string	(extract_costura) Directory where extracted DLLs/PDBs will be written
decompress	boolean	(extract_costura) Decompress gzip-compressed resources (default true)

Costura.Fody workflow: list_resources (confirm costura.* entries exist) → extract_costura output_directory=C:\extracted → load_assembly each extracted DLL → analyse normally with MCP tools.

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Skills Knowledge Base

A persistent reverse-engineering knowledge base stored in %APPDATA%\dnSpy\dnSpy.MCPServer\skills\. Each skill is a pair of files: a Markdown narrative ({id}.md) and a JSON technical record ({id}.json). Skills capture step-by-step procedures, magic values, crypto keys, algorithms, offsets, and generic prompts — so once you've reversed a packer or obfuscator, the knowledge is reusable.

Workflow: Before analysing a new binary, call search_skills to check for existing knowledge. After completing an analysis, call save_skill to record findings.

Tool	Description	Required params	Optional params
list_skills	List all skills in the knowledge base with ID, name, description, tags, and targets	—	tag
get_skill	Retrieve the full Markdown narrative and JSON technical record of a skill	skill_id	—
save_skill	Create or update a skill. Writes Markdown and/or JSON. Use merge=true to append findings without overwriting existing data	skill_id	name, description, tags, targets, markdown, json_data, merge
search_skills	Full-text search across all skill Markdown and JSON files. Returns matches with context snippets	query or tag	query, tag
delete_skill	Permanently delete a skill (both .md and .json files)	skill_id	—

Parameter details

Parameter	Type	Description
skill_id	string	Skill identifier — will be slugified (e.g. confuserex-unpacking). Use list_skills to see existing IDs
name	string	Human-readable skill name
description	string	Short summary of what the skill covers
tags	string	Comma-separated or JSON array of tags (e.g. packer,confuserex,unpacking)
targets	string	Comma-separated or JSON array of target binary names or hashes this skill applies to
markdown	string	Markdown narrative: what to do, why, key observations, procedure steps in prose
json_data	string	JSON object with technical details: procedure (steps with tool/prompt/expected), magic_values, crypto_keys, algorithms, offsets, findings, prompts (identify/apply/verify/troubleshoot)
merge	boolean	If true, deep-merge json_data into the existing record instead of replacing it (default false)
query	string	(search_skills) Keyword or phrase to search for in all skill files
tag	string	(list_skills, search_skills) Filter results to skills containing this tag substring

Example JSON skill record structure

{
  "id": "confuserex-unpacking",
  "name": "ConfuserEx Unpacking",
  "version": "1",
  "tags": ["packer", "confuserex", "unpacking"],
  "targets": ["MyProtectedApp.exe"],
  "description": "Step-by-step procedure to unpack ConfuserEx 1.x protected assemblies",
  "procedure": [
    { "step": 1, "tool": "detect_obfuscator", "prompt": "Detect which obfuscator was applied", "expected": "ConfuserEx v1.x" },
    { "step": 2, "tool": "start_debugging",   "prompt": "Launch under dnSpy with break_kind=EntryPoint", "expected": "Paused at entry point after .cctor" },
    { "step": 3, "tool": "dump_module_from_memory", "prompt": "Dump decrypted module from RAM", "expected": "Raw PE bytes" }
  ],
  "magic_values": { "key_offset": "0x1234", "xor_key": "0xDEADBEEF" },
  "crypto_keys": [],
  "algorithms": ["XOR", "AES-128-ECB"],
  "prompts": {
    "identify": "Use detect_obfuscator on the assembly. If ConfuserEx, proceed with this skill.",
    "apply": "Follow procedure steps 1-3. After dump, reload and deobfuscate.",
    "verify": "Decompile Main() — if readable C# appears, unpacking succeeded.",
    "troubleshoot": "If dump_module_from_memory fails, try dump_module_unpacked with fix_pe_header=true."
  }
}

---

Debug Tools

Interact with dnSpy's integrated debugger. Most tools require an active debug session.

Tool	Description	Required params	Optional params
get_debugger_state	Current state: IsDebugging, IsRunning, process list with thread/runtime counts	—	—
list_breakpoints	All registered code breakpoints with enabled state, bound count, and location	—	—
set_breakpoint	Set a breakpoint at a method entry point or specific IL offset. Supports an optional C# condition expression — only fires when the expression evaluates to true	assembly_name, type_full_name, method_name	il_offset, condition, file_path
remove_breakpoint	Remove a specific breakpoint	assembly_name, type_full_name, method_name	il_offset
clear_all_breakpoints	Remove every visible breakpoint	—	—
continue_debugger	Resume all paused processes (RunAll)	—	—
break_debugger	Pause all running processes (BreakAll)	—	—
stop_debugging	Terminate all active debug sessions	—	—
get_call_stack	Call stack of the currently selected (or first paused) thread — up to 50 frames	—	—
step_over	Step over the current statement. Blocks until the step completes (or timeout). Returns the new execution location (token, IL offset, module).	—	thread_id, process_id, timeout_seconds
step_into	Step into the next called method. Same blocking behaviour as step_over.	—	thread_id, process_id, timeout_seconds
step_out	Run until the current method returns to its caller.	—	thread_id, process_id, timeout_seconds
get_current_location	Read the top-frame execution location without stepping. Requires paused debugger.	—	thread_id, process_id
wait_for_pause	Poll until any process becomes paused (after a continue_debugger or start_debugging). Returns process info on pause, throws TimeoutException otherwise.	—	timeout_seconds
start_debugging	Launch an EXE under the dnSpy debugger. By default breaks at EntryPoint (after the module .cctor has run, so ConfuserEx-decrypted bodies are in RAM)	exe_path	arguments, working_directory, break_kind
attach_to_process	Attach the dnSpy debugger to a running .NET process by PID	process_id	—

Parameter details

Parameter	Type	Description
il_offset	integer	IL byte offset within the method body (default 0 = method entry)
condition	string	C# expression evaluated at each breakpoint hit — pauses only when true (e.g. "i > 100", "value != null")
exe_path	string	Absolute path to the EXE to launch
arguments	string	Command-line arguments to pass to the process
working_directory	string	Working directory for the launched process
break_kind	string	EntryPoint (default, pauses after .cctor) or ModuleCctorOrEntryPoint (pauses before .cctor)
thread_id	integer	Explicit thread ID to step/inspect. Defaults to current thread, then first paused thread.
timeout_seconds	integer	Max seconds to wait for a step or pause to complete (default 30)

Tip: Use start_debugging + break_kind: EntryPoint for ConfuserEx-packed assemblies — method bodies are decrypted by the time the breakpoint hits. Then use dump_module_from_memory or unpack_from_memory.

Step workflow: break_debugger (or wait for a BP) → get_current_location → step_over / step_into → inspect with get_local_variables or eval_expression → repeat.

---

Memory Dump & PE Tools

Extract raw bytes from a debugged process. Requires an active debug session unless otherwise noted.

Tool	Description	Required params	Optional params
list_runtime_modules	Enumerate all .NET modules loaded in the debugged processes with address, size, IsDynamic, IsInMemory, and AppDomain	—	process_id, name_filter
dump_module_from_memory	Extract a .NET module from process memory to a file (preserves file layout when possible)	module_name, output_path	process_id
read_process_memory	Read up to 64 KB from any process address; returns a formatted hex dump and Base64	address, size	process_id
write_process_memory	Write bytes to a process address (hot-patching). Accepts bytes_base64 (base64) or hex_bytes (e.g. "90 90 C3"). Useful for disabling checks without touching the binary on disk.	address, (bytes_base64 or hex_bytes)	process_id
get_local_variables	Read local variables and parameters from a paused stack frame; returns primitives, strings, and addresses for complex objects	—	frame_index, process_id
eval_expression	Evaluate a C# expression in the current paused frame context (Watch window equivalent). Returns typed value: primitive, string, or object address	expression	frame_index, process_id, func_eval_timeout_seconds
get_pe_sections	List PE section headers of a module in process memory (names, virtual addresses, sizes, characteristics)	module_name	process_id
dump_pe_section	Extract a specific PE section (e.g. .text, .data, .rsrc) from a module in process memory; writes to file and/or returns Base64	module_name, section_name	output_path, process_id
dump_module_unpacked	Dump a full module with memory-to-file layout conversion (produces a valid loadable PE). Handles .NET, native, and mixed-mode modules	module_name, output_path	process_id
dump_memory_to_file	Save a contiguous range of process memory to a file. Supports up to 256 MB	address, size, output_path	process_id

Parameter details

Parameter	Type	Description
process_id	integer	Target process ID (use get_debugger_state to find it). Defaults to the first paused process.
name_filter	string	Glob or regex filter on module name or filename
module_name	string	Module name, full filename, or basename (e.g. MyApp.dll). Use list_runtime_modules to find exact names.
output_path	string	Absolute path where the dumped bytes will be written. Parent directories are created automatically.
address	string	Memory address in hex (0x7FF000) or decimal
size	integer	Number of bytes to read/dump
bytes_base64	string	Bytes to write as base64 (use with write_process_memory)
hex_bytes	string	Bytes to write as hex string — "90 90 C3", "9090C3", "0x90 0x90" all accepted
frame_index	integer	Stack frame index (0 = top/innermost, default 0)
expression	string	C# expression to evaluate in the current frame context (e.g. "myObj.Field", "arr.Length")
func_eval_timeout_seconds	integer	Timeout for function evaluation calls in the debuggee (default 5)
section_name	string	PE section name (e.g. .text, .data, .rsrc)

Layout note: dump_module_from_memory reports IsFileLayout in its response. If false, use dump_module_unpacked instead for a corrected PE layout.

---

Static PE Analysis

Tools that operate on raw PE file bytes — no debug session required.

Tool	Description	Required params	Optional params
scan_pe_strings	Scan raw PE file bytes for printable ASCII and UTF-16 strings. Useful for finding URLs, API keys, IP addresses, and embedded plaintext in packed/obfuscated assemblies	assembly_name	min_length, encoding
unpack_from_memory	All-in-one ConfuserEx unpacker: launches the EXE under the debugger (pausing at EntryPoint after decryption), dumps the main module with PE-layout fix, and optionally stops the session. Output can be loaded in dnSpy or passed to deobfuscate_assembly	exe_path	output_path, stop_after_dump

Parameter details

Parameter	Type	Description
min_length	integer	Minimum string length to include (default 4)
encoding	string	ascii, unicode, or both (default both)
exe_path	string	Absolute path to the packed EXE to unpack
output_path	string	Destination for the unpacked PE (default: <original_name>_unpacked.exe next to the input)
stop_after_dump	boolean	Whether to stop the debug session after dumping (default true)

Workflow: scan_pe_strings → understand what the packed binary contains → unpack_from_memory → deobfuscate_assembly → load the clean file in dnSpy.

---

Deobfuscation Tools

Two de4dot integration modes: in-process (deobfuscate_assembly — uses bundled de4dot libraries, available in all builds) and external process (run_de4dot — spawns de4dot.exe, supports dynamic string decryption, available in all builds).

Tool	Description	Required params	Optional params
list_deobfuscators	List all obfuscator types supported by the in-process de4dot engine	—	—
detect_obfuscator	Detect which obfuscator was applied to a .NET assembly file on disk using de4dot's heuristic detection	file_path	—
deobfuscate_assembly	Deobfuscate a .NET assembly in-process: renames mangled symbols, deobfuscates control flow, decrypts strings	file_path, output_path	obfuscator_type, rename_symbols
save_deobfuscated	Return a previously deobfuscated file as a Base64-encoded blob. Useful when the output file cannot be accessed directly	file_path	—
run_de4dot	Run de4dot.exe as an external process. Supports dynamic string decryption and ConfuserEx method decryption that require a separate process	file_path	output_path, obfuscator_type, dont_rename, no_cflow_deob, string_decrypter, extra_args, de4dot_path, timeout_ms

Parameter details

Parameter	Type	Description
file_path	string	Absolute path to the .NET assembly on disk
output_path	string	Absolute path for the cleaned output assembly
obfuscator_type	string	Force a specific obfuscator type code (cr for ConfuserEx, un for unknown/auto, etc.). Omit to let de4dot auto-detect.
rename_symbols	boolean	(deobfuscate_assembly) Whether to rename obfuscated symbols (default true)
dont_rename	boolean	(run_de4dot) Skip symbol renaming if true (default false)
no_cflow_deob	boolean	(run_de4dot) Skip control-flow deobfuscation if true (default false)
string_decrypter	string	(run_de4dot) String decrypter mode: none, default, static, delegate, emulate
extra_args	string	(run_de4dot) Additional de4dot command-line arguments passed verbatim
de4dot_path	string	(run_de4dot) Override path to de4dot.exe. Defaults to well-known search paths.
timeout_ms	integer	(run_de4dot) Max milliseconds to wait for de4dot to finish (default 120000)

---

Window / Dialog Tools

Enumerate and dismiss dialog boxes (Win32 MessageBox, #32770 dialogs, and WPF windows) that appear in the dnSpy process — for example, error popups that block a debug session. No debug session required.

Tool	Description	Required params	Optional params
list_dialogs	List all active dialog/message-box windows. Returns title, HWND (hex), message text, and available button labels for each	—	—
close_dialog	Close a dialog by clicking a named button. Resolves the target by HWND or picks the first active dialog	—	hwnd, button

Parameter details

Parameter	Type	Description
hwnd	string	Hex HWND of the target dialog, as returned by list_dialogs (e.g. "1A2B3C"). If omitted, the first active dialog is used
button	string	Button to click (case-insensitive, EN and ES): ok/aceptar, yes/sí, no, cancel/cancelar, retry/reintentar, ignore/omitir. Default: ok

Button matching — the tool first checks common exact tokens (EN + ES), then falls back to substring matching. If no button matches, WM_CLOSE is sent to the dialog.

Example

// List all open dialogs
{ "tool": "list_dialogs" }

// Dismiss the first dialog by clicking OK
{ "tool": "close_dialog" }

// Dismiss a specific dialog by HWND, clicking Cancel
{ "tool": "close_dialog", "arguments": { "hwnd": "1A2B3C", "button": "cancel" } }

---

Utility

Tool	Description	Required params
list_tools	Return the full schema for every registered tool as JSON	—
get_mcp_config	Return the current MCP server configuration and the path to mcp-config.json	—
reload_mcp_config	Reload mcp-config.json from disk without restarting dnSpy	—

---

Pattern Syntax

Several tools accept a name_pattern or query parameter that supports both glob and regex syntax. The engine auto-detects the mode.

Mode	Detected when	Examples
Glob	Pattern contains only * or ? wildcards	Get*, *Controller, On?Click
Regex	Pattern contains any of ^ $ [ ( | + {	^Get[A-Z], Controller$, ^I[A-Z].*Service$
Substring	No special characters (for search_types only)	Player, Manager

All pattern matching is case-insensitive.

# Find all types whose name starts with "Player"
name_pattern: "Player*"

# Find all interfaces (start with I, followed by uppercase)
name_pattern: "^I[A-Z]"

# Find methods ending in "Async"
name_pattern: "Async$"

# Find all Get* or Set* methods
name_pattern: "^(Get|Set)[A-Z]"

---

Pagination

List operations return paginated results. The default page size is 50 items.

{
  "items": [ ... ],
  "total_count": 312,
  "returned_count": 50,
  "nextCursor": "eyJvZmZzZXQiOjUwLCJwYWdlU2l6ZSI6NTB9"
}

To fetch the next page, pass the nextCursor value as the cursor argument in the next call. When nextCursor is absent, you have reached the last page.

---

Usage Examples

Workflow: explore an unknown assembly

1. list_assemblies                           → find "UnityEngine.CoreModule"
2. get_assembly_info  assembly=UnityEngine…  → see namespaces
3. list_types  assembly=…  namespace=UnityEngine  name_pattern="*Manager"
4. get_type_info  assembly=…  type=UnityEngine.NetworkManager
5. decompile_method  …  method=Awake

Search with regex across all assemblies

{ "tool": "search_types", "arguments": { "query": "^I[A-Z].*Repository$" } }

Dump a Unity game module from memory

{ "tool": "list_runtime_modules", "arguments": { "name_filter": "Assembly-CSharp*" } }

{ "tool": "dump_module_from_memory", "arguments": {
    "module_name": "Assembly-CSharp.dll",
    "output_path": "C:\\dump\\Assembly-CSharp_dump.dll"
}}

Set a breakpoint and inspect the call stack

{ "tool": "set_breakpoint", "arguments": {
    "assembly_name": "Assembly-CSharp",
    "type_full_name": "PlayerController",
    "method_name": "TakeDamage"
}}

{ "tool": "get_call_stack" }

Change a private method to public and save

{ "tool": "change_member_visibility", "arguments": {
    "assembly_name": "MyAssembly",
    "type_full_name": "MyNamespace.MyClass",
    "member_kind": "method",
    "member_name": "InternalHelper",
    "new_visibility": "public"
}}

{ "tool": "save_assembly", "arguments": {
    "assembly_name": "MyAssembly",
    "output_path": "C:\\patched\\MyAssembly.dll"
}}

Read process memory at a known address

{ "tool": "read_process_memory", "arguments": {
    "address": "0x7FFE00001000",
    "size": 256
}}

Unpack a ConfuserEx-protected EXE and deobfuscate it

1. scan_pe_strings  assembly_name=MyApp  → confirm it's packed (few readable strings)
2. unpack_from_memory  exe_path=C:\MyApp.exe  output_path=C:\MyApp_unpacked.exe
3. detect_obfuscator  file_path=C:\MyApp_unpacked.exe  → identify remaining obfuscation
4. deobfuscate_assembly  file_path=C:\MyApp_unpacked.exe  output_path=C:\MyApp_clean.dll

Patch anti-debug stubs and save a clean binary

1. list_pinvoke_methods  assembly=MyApp  type=AntiDebugClass
   → finds "CheckRemoteDebuggerPresent" → kernel32.dll
2. patch_method_to_ret  assembly=MyApp  type=AntiDebugClass  method=CheckRemoteDebuggerPresent
3. save_assembly  assembly=MyApp  output_path=C:\MyApp_patched.exe

Load an assembly from disk or from a running process

// Load a .NET DLL from disk
{ "tool": "load_assembly", "arguments": {
    "file_path": "C:\\dump\\MyApp_unpacked.dll"
}}

// Load a raw memory-layout dump (VAs instead of file offsets)
{ "tool": "load_assembly", "arguments": {
    "file_path": "C:\\dump\\MyApp_memdump.bin",
    "memory_layout": true
}}

// Dump from a running process and load directly into dnSpy
{ "tool": "load_assembly", "arguments": {
    "pid": 1234,
    "module_name": "MyPlugin.dll"
}}

Dismiss a dialog that is blocking a debug session

{ "tool": "list_dialogs" }
// → [1] Title: "Error de depuración"
//       Hwnd: 1A2B3C  |  Type: Win32 (#32770)
//       Message: "No se puede continuar la operación."
//       Buttons: Aceptar, Cancelar

{ "tool": "close_dialog", "arguments": { "hwnd": "1A2B3C", "button": "aceptar" } }
// → Clicked 'Aceptar' in dialog 'Error de depuración'.

Find all callers and usages of a suspicious type

{ "tool": "find_who_uses_type", "arguments": {
    "assembly_name": "MyAssembly",
    "type_full_name": "MyNamespace.ObfuscatedLicenseChecker"
}}

{ "tool": "find_who_writes_field", "arguments": {
    "assembly_name": "MyAssembly",
    "type_full_name": "MyNamespace.ObfuscatedLicenseChecker",
    "field_name": "isValid"
}}

---

Architecture

File	Responsibility
src/Communication/McpServer.cs	HTTP/SSE listener, JSON-RPC dispatch
src/Application/McpTools.cs	Central tool registry, schema definitions, routing
src/Application/AssemblyTools.cs	Assembly/type listing, P/Invoke analysis
src/Application/TypeTools.cs	Type detail, methods, IL, BFS path analysis
src/Application/EditTools.cs	Metadata editing, decompilation, assembly saving, method patching
src/Application/DebugTools.cs	Debugger state, breakpoints, stepping, process launch/attach
src/Application/DumpTools.cs	Runtime module enumeration, memory dump, PE section tools
src/Application/MemoryInspectTools.cs	Local variable inspection from paused debug frame
src/Application/UsageFindingCommandTools.cs	Cross-assembly IL usage analysis (callers, field reads/writes)
src/Application/CodeAnalysisHelpers.cs	Static call-graph, dependency chain, dead code analysis
src/Application/De4dotTools.cs	de4dot in-process integration; available in all builds
src/Application/SkillsTools.cs	Persistent skills knowledge base (Markdown + JSON) in %APPDATA%\dnSpy\dnSpy.MCPServer\skills\
src/Application/ScriptTools.cs	Roslyn C# scripting (run_script)
src/Application/WindowTools.cs	Win32 + WPF dialog enumeration and dismissal
src/Presentation/TheExtension.cs	MEF entry point, server lifecycle
src/Contracts/McpProtocol.cs	MCP DTOs (ToolInfo, CallToolResult, …)

---

Project Structure

dnSpy.MCP.Server/
├── dnSpy.MCP.Server.csproj   # Multi-target: net48 + net10.0-windows
├── CHANGELOG.md
├── README.md
├── RELEASE_NOTES.md
└── src/
    ├── Application/
    │   ├── AssemblyTools.cs         # Assembly & type listing
    │   ├── TypeTools.cs             # Type internals + IL
    │   ├── EditTools.cs             # Metadata editing, method patching
    │   ├── DebugTools.cs            # Debugger integration
    │   ├── DumpTools.cs             # Memory dump & PE tools
    │   ├── MemoryInspectTools.cs    # Local variable inspection
    │   ├── UsageFindingCommandTools.cs  # IL usage analysis
    │   ├── CodeAnalysisHelpers.cs   # Call-graph & dependency analysis
    │   ├── De4dotTools.cs           # de4dot deobfuscation (all builds)
    │   ├── SkillsTools.cs           # Skills knowledge base (MD + JSON)
    │   ├── ScriptTools.cs           # Roslyn C# scripting
    │   ├── WindowTools.cs           # Win32/WPF dialog management
    │   └── McpTools.cs              # Tool registry & routing
    ├── Communication/
    │   └── McpServer.cs             # HTTP/SSE server
    ├── Contracts/
    │   └── McpProtocol.cs           # DTO types
    ├── Helper/
    │   └── McpLogger.cs
    └── Presentation/
        ├── TheExtension.cs          # MEF export / entry point
        ├── ToolbarCommands.cs
        ├── McpSettings.cs
        └── McpSettingsPage.cs

---

Configuration

Port

Default port is 3100. To change it, edit src/Presentation/McpSettings.cs:

public const int DefaultPort = 3100;

Rebuild the project after changing this value.

Verify the server is running

# Windows (PowerShell)
Invoke-RestMethod http://localhost:3100

# Windows (cmd)
curl http://localhost:3100

# Check port is listening
netstat -ano | findstr :3100

---

Troubleshooting

Symptom	Likely cause	Solution
Extension not loading	DLL not in dnSpy bin folder	Rebuild with -c Release; check output path in .csproj
Connection refused on port 3100	Server failed to start	Check dnSpy's log window; port 3100 may be in use — netstat -ano | findstr :3100
Tool returns Unknown tool: …	Name typo or outdated client cache	Call list_tools to see the current tool list
Assembly not found	Name mismatch	Call list_assemblies and use the exact Name value shown
Type not found	Wrong type_full_name	Use list_types or search_types to find the exact full name
Debugger is not active	No debug session running	Start debugging via start_debugging or dnSpy's Debug menu
No paused process found	Process is still running	Call break_debugger first
dump_module_from_memory returns no bytes	Module has no address (pure dynamic)	Some in-memory modules emitted by reflection emit cannot be dumped
Dump IsFileLayout: false	Memory layout dump	Use dump_module_unpacked instead — it performs the layout fix automatically
unpack_from_memory fails with anti-debug error	Process kills itself before EntryPoint	Use patch_method_to_ret to neutralize anti-debug methods first, save the patched binary, then retry
Failed to reconnect when adding MCP server	Wrong transport type	Use --transport sse with Claude Code CLI, not streamable-http. URL must point to /sse endpoint: http://localhost:3100/sse
dump_cordbg_il returns E_NOINTERFACE errors	COM STA apartment threading	ICorDebugModule COM objects belong to the CorDebug engine thread; calling from another STA fails. This is a known limitation — use dump_module_unpacked instead for memory dumps.
Debug session appears frozen / no response	A dialog box is blocking the UI thread	Call list_dialogs to detect open dialogs, then close_dialog to dismiss them and unblock the session.

---

Contributing

1. Fork or branch from master
2. Implement your changes under src/Application/ or src/Communication/
3. Register new tools in McpTools.cs (GetAvailableTools + ExecuteTool switch)
4. Build with dotnet build … --nologo — must produce 0 errors, 0 warnings
5. Manually test via any MCP client (list_tools to verify registration)
6. Submit a PR with a description of the new tool(s) and their parameters

---

License

GNU General Public License v3.0 — see LICENSE for details.