Memorylens Mcp

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MemoryLens MCP

On-demand .NET memory profiling with concrete, AI-actionable code fix suggestions — wraps JetBrains dotMemory with a heuristic-based rule engine.

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Hosted deployment

A hosted deployment is available on Fronteir AI.

Quick Start

VS Code / Visual Studio (via dnx)

Add to your MCP settings (.vscode/mcp.json or VS settings):

{
  "servers": {
    "memorylens": {
      "type": "stdio",
      "command": "dnx",
      "args": ["MemoryLens.Mcp", "--yes"]
    }
  }
}

Claude Code Plugin

claude install gh:MarcelRoozekrans/memorylens-mcp

.NET Global Tool

dotnet tool install -g MemoryLens.Mcp

Prerequisites

• .NET 10 SDK or later
• JetBrains dotMemory CLI (see below for installation options)

dotMemory CLI Installation

MemoryLens MCP automatically downloads and caches the JetBrains dotMemory CLI on first use via the ensure_dotmemory tool — no manual installation required on supported platforms.

Supported Platforms (auto-download)

| Platform | Architecture | |---|---| | Windows | x64, x86, ARM64 | | Linux (glibc) | x64, ARM64, ARM | | Linux (musl) | x64, ARM64 | | macOS | x64 (Intel), ARM64 (Apple Silicon) |

Cache Location

Downloaded binaries are cached at ~/.memorylens/tools/dotmemory/{version}/. Old versions are not auto-removed — delete the directory manually to free disk space.

Unsupported Platforms

Platforms not listed above (e.g. FreeBSD, Linux x86) cannot use auto-download. Set DOTMEMORY_PATH to point to an existing dotMemory CLI executable:

export DOTMEMORY_PATH="/path/to/dotMemory.sh"   # Linux/macOS
set DOTMEMORY_PATH=C:\path\to\dotMemory.exe      # Windows

Find dotMemory CLI in JetBrains Toolbox:

• Linux: ~/.local/share/JetBrains/Toolbox/apps/rider/tools/profiler/dotMemory.sh
• Windows: %LOCALAPPDATA%\JetBrains\Toolbox\apps\rider\tools\profiler\dotMemory.exe

Manual Fallback Discovery

If auto-download is unavailable, MemoryLens MCP falls back through these discovery modes in order:

1. DOTMEMORY_PATH environment variable — explicit path to the CLI executable
2. System PATH — searches for dotMemory.sh / dotMemory (Linux/macOS) or dotMemory.exe (Windows)
3. Local .NET tool manifest — dotnet tool install dotnet-dotmemory --local
4. Global .NET tool — dotnet tool install -g dotnet-dotmemory (legacy fallback)

Error Scenarios

| Error | Cause | Fix | |---|---|---| | Platform '...' is not supported | Unsupported OS/arch | Set DOTMEMORY_PATH | | Network/download failure | No internet / NuGet unreachable | Set DOTMEMORY_PATH or retry ensure_dotmemory | | chmod +x failed | Read-only filesystem | Set DOTMEMORY_PATH to a writable location | | dotMemory CLI not found | All discovery modes failed | Run ensure_dotmemory or set DOTMEMORY_PATH |

Available MCP Tools

| Tool | Description | |------|-------------| | ensure_dotmemory | Downloads and verifies the JetBrains dotMemory CLI tool is available | | list_processes | Lists running .NET processes available for profiling | | snapshot | Captures a single memory snapshot of a target process | | compare_snapshots | Captures two snapshots with configurable delay and compares them | | analyze | Runs the rule engine against a captured snapshot and returns findings | | get_rules | Lists all available analysis rules with their metadata |

Built-in Rules

| ID | Severity | Category | Description | |----|----------|----------|-------------| | ML001 | critical | leak | Event handler leak detected | | ML002 | critical | leak | Static collection growing unbounded | | ML003 | high | leak | Disposable object not disposed | | ML004 | high | fragmentation | Large Object Heap fragmentation | | ML005 | medium | retention | Object retained longer than expected | | ML006 | medium | allocation | Excessive allocations in hot path | | ML007 | medium | retention | Closure retaining unexpected references | | ML008 | low | allocation | Array/list resizing without capacity hint | | ML009 | low | pattern | Finalizer without Dispose pattern | | ML010 | low | pattern | String interning opportunity |

Configuration

Create a .memorylens.json file in your project root to customize rule behavior:

{
  "rules": {
    "ML001": { "enabled": true, "severity": "critical" },
    "ML002": { "enabled": true, "severity": "critical" },
    "ML003": { "enabled": true, "severity": "high" },
    "ML004": { "enabled": true, "severity": "high" },
    "ML005": { "enabled": true, "severity": "medium" },
    "ML006": { "enabled": true, "severity": "medium" },
    "ML007": { "enabled": true, "severity": "medium" },
    "ML008": { "enabled": true, "severity": "low" },
    "ML009": { "enabled": true, "severity": "low" },
    "ML010": { "enabled": true, "severity": "low" }
  }
}

Usage Examples

Single Snapshot

Capture a memory snapshot of a running process to inspect current memory state:

> /memorylens
> Take a snapshot of my running API (PID 12345)

Claude will call ensure_dotmemory, then snapshot with the target PID, then analyze the result and present findings ordered by severity.

Before/After Comparison

Detect memory growth by comparing two snapshots taken with a delay:

> /memorylens
> Check if my app has a memory leak — compare before and after processing 1000 requests

Claude will call compare_snapshots with a configurable wait period, then analyze the diff to identify objects that grew between snapshots.

License

[MIT](LICENSE)

Source & license

This open-source MCP server is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: MarcelRoozekrans
• Source: MarcelRoozekrans/memorylens-mcp
• License: MIT

Install and usage instructions live in the source repository linked above.