MCP Mat

Name: MCP Mat
Author: codelipenghui

by codelipenghuiversion 0.1.0i★ –iRuns on your computer

Registry nameio.github.codelipenghui/mcp-mat

Install

Overview

Description from the maker (original English)

Headless Eclipse MAT MCP server for Java heap dump analysis

PopNx MCP’s three pillars

These three are never merged into one score: opinions, measurements and popularity are different things.

User voiceiNo reviews yetReviews open together with accounts in a later step
Our basic checksi1 of 1 passedChecked from public information; code not scanned yet
UsageiNot measured yet★ –

What you can do with it

We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.

Connection: Runs on your computer
Transport: stdio
Category: Other

Install

Pick the AI app you use, then copy the settings.

Before you install

Basic checks: 1 of 1 passed
Runs on your computer with your user’s permissions (files, network, apps).
You fill in yourself: MAT_HOME, JAVA_PATH, MAT_XMX_MB

You need

npmNode.js installed (for the npx command)

Which app do you use?

ClaudeClaude CodeCursorVS CodeChatGPT

Pick your app above. We remember it, so next time the button says “Install in …”.

Open Claude Desktop → Settings → Developer → Edit Config, and paste this into claude_desktop_config.json

{
  "mcpServers": {
    "mat": {
      "command": "npx",
      "args": [
        "-y",
        "mcp-mat"
      ],
      "env": {
        "MAT_HOME": "your-value",
        "JAVA_PATH": "your-value",
        "MAT_XMX_MB": "your-value"
      }
    }
  }
}

Run this in your terminal

claude mcp add mat --env MAT_HOME=your-value --env JAVA_PATH=your-value --env MAT_XMX_MB=your-value -- npx -y mcp-mat

Fill in the empty values before running it.

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

{
  "mcpServers": {
    "mat": {
      "command": "npx",
      "args": [
        "-y",
        "mcp-mat"
      ],
      "env": {
        "MAT_HOME": "your-value",
        "JAVA_PATH": "your-value",
        "MAT_XMX_MB": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "mat": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "mcp-mat"
      ],
      "env": {
        "MAT_HOME": "your-value",
        "JAVA_PATH": "your-value",
        "MAT_XMX_MB": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

This one runs on your computer, and ChatGPT can only connect to servers on the internet. Pick another app.

Your choice stays on this device in a cookie; no account needed.

Values you fill in

MAT_HOME env
Path to Eclipse MAT installation directory (e.g., /Applications/MemoryAnalyzer.app/Contents/Eclipse)
JAVA_PATH env
Path to Java executable (default: java)
MAT_XMX_MB env
Maximum JVM heap size in MB for MAT (default: 4096)

These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

What it can do

Runs on your computer; the tool list appears in your AI app after you install it.

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 7, 2026

✓ Pass
Maker matches the repo
The registry name was verified with the GitHub account codelipenghui, which owns the repo
… Not checked yet
Still maintained
We have not read this repo from GitHub yet
… Not checked yet
Has a licence
We have not read this repo from GitHub yet
– Not applicable
Endpoint responds
This one runs on your computer; there is no internet endpoint
– Not applicable
Sign-in with OAuth
Runs on your computer and uses local settings instead
… Not checked yet
No hidden instructions in tool descriptions
Runs on your computer; we can only read tool lists from internet endpoints

Compared with others in Otheri

More stars than 0% of the other 32655 servers in this category
Published to the registry more recently than 4% of the other 32655 servers in this category
Basic checks equal to or better than 100% of the other 32655 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Common questions

Is MCP Mat safe?

It passed 1 of 1 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.

What keys or codes does it need?

The registry does not list a required key, though some servers ask you to sign in on first use.

Does it run on my computer or in the cloud?

It runs on your computer. Your AI app starts it when needed, and data does not pass through the maker’s servers (unless it calls an online service itself).

Is it still maintained?

The GitHub repo last changed –, and the latest version (0.1.0) reached the registry 8 months ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. You also need Node.js on your computer.

What can I use instead?

In the same category: Spec Driven Development, Remote Desktop Commander, SuperCollider

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README from the maker

Open the README

Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.

mcp-mat

Headless MCP server for Eclipse MAT using direct java -jar org.eclipse.equinox.launcher_*.jar execution.

Features

mat_healthcheck — Validate MAT launcher and Java runtime availability
mat_parse_report — Run predefined MAT reports (leak suspects, system overview, etc.)
mat_oql_query — Execute OQL queries and return inline results
mat_run_command — Execute 56 built-in MAT analysis commands (histogram, dominator_tree, path2gc, thread_overview, etc.)
mat_index_status — Check whether MAT index artifacts exist for a heap dump
mat_oql_spec — Return OQL parser guidance and supported patterns

Supported Commands (`mat_run_command`)

Dominator tree analysis

dominator_tree, show_dominator_tree, immediate_dominators, big_drops_in_dominator_tree

Path to GC roots

path2gc, merge_shortest_paths, gc_roots

Histogram & object listing

histogram, delta_histogram*, list_objects, group_by_value, duplicate_classes

Leak detection

leakhunter, leakhunter2*, find_leaks, find_leaks2*, reference_leak

Thread analysis

thread_overview, thread_details, thread_stack

Collection analysis

collection_fill_ratio, collections_grouped_by_size, array_fill_ratio, arrays_grouped_by_size, hash_entries, map_collision_ratio, extract_list_values, hash_set_values, primitive_arrays_with_a_constant_value

Reference analysis

references_statistics, weak_references_statistics, soft_references_statistics, phantom_references_statistics, finalizer_references_statistics

Finalizer analysis

finalizer_overview, finalizer_thread, finalizer_queue, finalizer_in_processing, finalizer_thread_locals

Retained set

show_retained_set, customized_retained_set

Component & top consumers

component_report, component_report_top, top_consumers, top_consumers_html, pie_biggest_objects

String & memory waste

find_strings, waste_in_char_arrays

Heap info & misc

heap_dump_overview, unreachable_objects, system_properties, class_references, comparison_report*

Eclipse/OSGi specific

bundle_registry, leaking_bundles

Export

export_hprof

\* Requires a baseline heap dump (second .hprof file).

OQL mode notes

This server normalizes client OQL input and wraps it for MAT parse-app command mode.
You can send OQL with or without outer quotes.
For class ranking and top consumers, prefer mat_parse_report with org.eclipse.mat.api:overview and parse Class_Histogram*.txt.
For object inspection, use simple field-level OQL patterns (INSTANCEOF, OBJECTS 0x...).

Environment

All environment variables are optional:

MAT_HOME
MAT_LAUNCHER
JAVA_PATH (default java)
MAT_XMX_MB (default 4096)
MAT_TIMEOUT_SEC (default 1800)
MAT_CONFIG_DIR (default /tmp/mat-config)
MAT_DATA_DIR (default /tmp/mat-workspace)
MAT_DEBUG (default false)
MAT_DEBUG_LOG_DIR (default /tmp/mcp-mat-logs)
MAT_PRIVACY_MODE (default false)
MAT_OQL_MAX_BYTES (default 16384)
MAT_RESULT_PREVIEW_LINES (default 20)
MAT_STDIO_TAIL_CHARS (default 4000)

Run

npm install

npm run build MAT_HOME=/path/to/mat node dist/src/server.js

Test

npm test

Install via npx

No build step required. Install directly from npm:

Claude Code

Add to ~/.claude/settings.json or project .claude/settings.json:

"mcpServers": { "mat": { "command": "npx", "args": ["-y", "mcp-mat"], "env": { "MAT_HOME": "/Applications/MemoryAnalyzer.app/Contents/Eclipse" } } } }

Codex

codex mcp add \

--env MAT_HOME=/Applications/MemoryAnalyzer.app/Contents/Eclipse \ mat \ npx -y mcp-mat

Install in Claude Code (from source)

Add the MCP server to Claude Code settings (~/.claude/settings.json or project .claude/settings.json):

"mcpServers": { "mat": { "command": "node", "args": ["/path/to/mcp-mat/dist/src/server.js"], "env": { "MAT_HOME": "/Applications/MemoryAnalyzer.app/Contents/Eclipse" } } } }

Install in Codex (from source)

Build first:

cd /path/to/mcp-mat

npm install npm run build

Add MCP server to Codex:

codex mcp add \

--env MAT_HOME=/Applications/MemoryAnalyzer.app/Contents/Eclipse \ mat \ node /path/to/mcp-mat/dist/src/server.js

Verify:

codex mcp list

codex mcp get mat --json

If you need to update the entry:

codex mcp remove mat

then run codex mcp add ... again

Equivalent ~/.codex/config.toml entry:

[mcp_servers.mat]

command = "node" args = ["/path/to/mcp-mat/dist/src/server.js"]

[mcp_servers.mat.env] MAT_HOME = "/Applications/MemoryAnalyzer.app/Contents/Eclipse"

MCP Mat

Overview

PopNx MCP’s three pillars

What you can do with it

Install

Before you install

Values you fill in

What it can do

Basic checksi

Maker matches the repo

Still maintained

Has a licence

Endpoint responds

Sign-in with OAuth

No hidden instructions in tool descriptions

Compared with others in Otheri

Common questions

Alternatives

Spec Driven Development

Remote Desktop Commander

SuperCollider

README from the maker

mcp-mat

Features

Supported Commands (mat_run_command)

Dominator tree analysis

Path to GC roots

Histogram & object listing

Leak detection

Thread analysis

Collection analysis

Reference analysis

Finalizer analysis

Retained set

Component & top consumers

String & memory waste

Heap info & misc

Eclipse/OSGi specific

Export

OQL mode notes

Environment

Run

Test

Install via npx

Claude Code

Codex

Install in Claude Code (from source)

Install in Codex (from source)

then run codex mcp add ... again

Supported Commands (`mat_run_command`)