Path of Exile 2 Build Optimizer MCP

Community Project Disclaimer

This is an independent, fan-made community project built out of love for Path of Exile 2. It is not affiliated with, endorsed by, or officially connected to Grinding Gear Games in any way. Path of Exile is a trademark of Grinding Gear Games. All game data and assets remain the property of their respective owners.

A Model Context Protocol (MCP) server for Path of Exile 2 character analysis and optimization. Provides 38 MCP tools for AI-powered build analysis, passive tree analysis, item mod validation, support gem validation, and Path of Building integration (including a live bridge to a running PoB instance).

What is This?

This is an MCP server - a backend service that gives AI assistants (like Claude, ChatGPT, Cursor, etc.) the ability to analyze your Path of Exile 2 characters and provide optimization recommendations.

What it does:

• Fetches your character data from poe.ninja
• Analyzes defensive stats, skills, gear, and passive tree
• Validates support gem combinations (prevents invalid recommendations)
• Inspects spell and support gem data
• Imports/exports Path of Building codes
• Compares your build to top ladder players
• Explains PoE2 game mechanics

What you need:

• An AI assistant that supports MCP (Claude Desktop, ChatGPT Desktop, Cursor, Windsurf, etc.)
• Python 3.9+ installed
• Your PoE2 character on poe.ninja (public profile)

Quick Start

1. Install

Option A: PyPI (Recommended)

pip install poe2-mcp

Option B: From Source

git clone https://github.com/HivemindOverlord/poe2-mcp.git
cd poe2-mcp
pip install -e .

2. Connect to Your AI Assistant

Choose your platform below:

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Claude Desktop Integration

Option A: Manual Configuration (Recommended for Development)

Edit your Claude Desktop config file:

• Windows: %APPDATA%\Claude\claude_desktop_config.json
• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json

The right config depends on how you installed. Pick one.

A1. If you ran pip install poe2-mcp (Recommended)

Use the poe2-mcp console script. It's on your PATH after pip install and works on every platform — no absolute path needed:

{
  "mcpServers": {
    "poe2-optimizer": {
      "command": "poe2-mcp",
      "env": {}
    }
  }
}

If Claude Desktop reports it can't find poe2-mcp, your pip install directory isn't on Claude Desktop's PATH. Either run which poe2-mcp (where poe2-mcp on Windows) and use the absolute path, or fall back to python -m:

{
  "mcpServers": {
    "poe2-optimizer": {
      "command": "python",
      "args": ["-m", "src.mcp_server"],
      "env": {}
    }
  }
}

A2. If you cloned + pip install -e . from source

Point at launch.py directly. It does some Windows-specific UTF-8 setup that the bare console script skips:

Windows:

{
  "mcpServers": {
    "poe2-optimizer": {
      "command": "python",
      "args": ["C:\\Users\\YourName\\poe2-mcp\\launch.py"],
      "env": {}
    }
  }
}

macOS/Linux:

{
  "mcpServers": {
    "poe2-optimizer": {
      "command": "python3",
      "args": ["/Users/YourName/poe2-mcp/launch.py"],
      "env": {}
    }
  }
}

Restart Claude Desktop after editing the config. The server will appear in your MCP tools.

Option B: Download .mcpb Bundle (One-Click Install)

Pre-built MCP bundles are available for one-click installation in Claude Desktop:

1. Download poe2-mcp-1.0.0.mcpb from the GitHub Releases
2. In Claude Desktop: Settings > Extensions > Install Extension
3. Select the downloaded .mcpb file

Note: The bundle is ~109MB as it includes all game data files. Python 3.9+ must be installed on your system.

Recommendation: For development or if you want automatic updates, use Option A (manual configuration) with pip install poe2-mcp.

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Other AI Platforms

MCP is an open standard supported by multiple AI platforms:

OpenAI ChatGPT Desktop

ChatGPT desktop app supports MCP servers. Configuration varies by version - check OpenAI's documentation for current setup instructions.

Cursor AI

Cursor supports MCP via SSE protocol. Add to your Cursor settings:

{
  "mcp": {
    "servers": {
      "poe2-optimizer": {
        "command": "python",
        "args": ["/path/to/poe2-mcp/launch.py"]
      }
    }
  }
}

Windsurf

Windsurf has a built-in MCP Plugin Store. You can either:

• Search for "poe2" in the plugin store (if published)
• Manually add the server path in settings

Claude Code (CLI)

# In your project directory
claude mcp add poe2-optimizer python /path/to/poe2-mcp/launch.py

Other Compatible Clients

• Zed Editor
• Replit
• Codeium
• Sourcegraph
• Microsoft Semantic Kernel
• Salesforce Agentforce

Check each platform's documentation for MCP server configuration.

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Available Tools (38 Registered)

Once connected, you can ask your AI assistant to use these tools. The authoritative list is _register_tools() in src/mcp_server.py — verify the live count with:

python -c "import re; print(len(re.findall(r'types\.Tool\(\s*name=', open('src/mcp_server.py').read())))"

Character Analysis

Tool	Description
analyze_character	Full character analysis (defenses, skills, gear, passives); exposes raw passive_node_ids
import_poe_ninja_url	Import character from a poe.ninja profile URL (league-segment aware)
compare_to_top_players	Compare your build to ladder leaders (protobuf builds API)
analyze_passive_tree	Analyze allocated passive nodes with pathfinding
calculate_character_dps	Server-side spell DPS, including the optional DoT layer (ignite/poison/bleed + skill DoT)
get_live_game_state	Read the running PoE2 client's Client.txt (character, area, deaths) — local, no network
get_game_config	Read local game config INI (gateway, input mode, renderer)

Validation & Inspection

Tool	Description
validate_support_combination	Check if support gems work together (hard + semantic conflicts)
validate_build_constraints	Validate build against game rules (flat/nested/legacy resistance schemas, null-tolerant)
reconcile_defensive_stats	Diff local EHP/defense calcs against poe.ninja's computed stats
inspect_support_gem	View complete support gem data (incl. spirit reservation)
inspect_spell_gem	View complete spell gem data (per-level costs/reservation)
list_all_supports	List all available support gems
list_all_spells	List all available spell gems

Passive Tree Data

Tool	Description
list_all_keystones	List all keystones with full stats
inspect_keystone	Get complete keystone details by name
list_all_notables	List all notable passives with stats
inspect_passive_node	Get details for any passive node
check_tree_freshness	Report passive-tree data revision vs poe.ninja

Base Item Data

Tool	Description
list_all_base_items	List all base item types
inspect_base_item	Get details for a specific base item

Item Mod Data

Tool	Description
inspect_mod	Get complete details for a specific mod by ID
list_all_mods	List mods with filtering by type (PREFIX/SUFFIX/IMPLICIT)
search_mods_by_stat	Search for mods by keyword (e.g., "fire", "life")
get_mod_tiers	Show all tier variations of a mod family
validate_item_mods	Check if mods can legally exist together on an item
get_available_mods	List all mods available for a generation type

Knowledge & Discovery

Tool	Description
explain_mechanic	Explain PoE2 mechanics / stat ids; tiered exact → substring → BM25 lexical; cluster: true dumps a mechanic's full stat-id + source web
find_stat_sources	Reverse lookup: which skills / passives / ascendancy nodes / mods grant a stat
get_formula	Get calculation formulas

Path of Building (file-based)

Tool	Description
import_pob	Import a PoB build — from pob_file_path, raw pob_xml, or inline pob_code
export_pob	Export build to PoB format
get_pob_code	Get a character's PoB export via the poe.ninja profile API

Trade & Items

Tool	Description
search_items	Search local item database
search_trade_items	Search official trade site (requires auth)
setup_trade_auth	Set up trade site authentication

Utility

Tool	Description
health_check	Check server status
clear_cache	Clear cached data

Live Path of Building bridge: src/pob/client.py + the pob_addon/ Lua addon implement a TCP bridge (127.0.0.1:49085) to a running PoB instance. The bridge client exists but its pob_* operations are not currently registered as MCP tools — they are used internally / via the integration test suite. They are not in the 38 above.

Not registered: DPS/EHP standalone calculators, optimizers, and the live pob_* bridge ops have handlers/clients but no tool registration yet.

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Example Usage

Once configured, just talk to your AI naturally:

"Analyze my character TomawarTheFourth from account Tomawar"

"Import this poe.ninja URL: https://poe.ninja/poe2/builds/char/..."

"Can I use Faster Projectiles and Slower Projectiles together?" (uses validate_support_combination)

"Show me all support gems that work with projectiles" (uses list_all_supports)

"What keystones are available for life builds?" (uses list_all_keystones)

"Tell me about Chaos Inoculation" (uses inspect_keystone)

"Compare my build to top Witchhunter players"

"Explain how armor works in PoE2"

"What prefixes can roll on items?" (uses get_available_mods)

"Show me all tiers of the Strength mod" (uses get_mod_tiers)

"Can Strength1 and Strength2 exist on the same item?" (uses validate_item_mods)

"Search for fire resistance mods" (uses search_mods_by_stat)

The AI will use the appropriate tools automatically.

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Trade API Authentication (Optional)

For search_trade_items to work, you need to authenticate with pathofexile.com:

pip install playwright
playwright install chromium
python scripts/setup_trade_auth.py

This opens a browser for you to log in, then saves your session cookie.

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Local Game Database

The server includes a local database with:

• 4,975+ passive tree nodes
• 335+ ascendancy nodes (99% coverage)
• 14,269 item modifiers (2,252 prefixes, 2,037 suffixes, 8,930 implicits)
• Complete skill gem data from Path of Building
• Support gem effects and interactions
• Base items and unique items

Data is loaded from data/ directory on startup.

Centralized Game-Data Distribution (new in 1.0.2)

You no longer need to extract .datc64 files from your own PoE2 install. The MCP automatically downloads the maintained game-data bundle from this repo's GitHub Releases on first run and after each patch (resolves #53).

How it works:

1. launch.py calls src/data/data_distributor.ensure_data_current() during startup
2. It compares data/version.json (local) against the latest release tagged data-v*
3. If newer data is available, it downloads poe2-data.zip and unzips into data/
4. The MCP starts with current data

Opt out (run your own local extraction instead):

export POE2_MCP_NO_DATA_FETCH=1   # macOS/Linux
$env:POE2_MCP_NO_DATA_FETCH=1     # PowerShell

Then extract via scripts/extract_poe2_data.py against your own licensed PoE2 install.

Manual refresh:

python -m src.data.data_distributor

Data policy: The bundle is extracted exclusively from the maintainer's licensed PoE2 install via the in-repo extraction scripts. No third-party wiki / scraped data is bundled. See CLAUDE.md "Data Source Policy" for details.

Data currency & drift protection: The shipped datasets are extracted from the full Patch 0.5 table set (1,019 canonical .datc64 balance tables via scripts/extract_balance_tables_v1.py), versioned in data/game/version.json (data-v0.5.0-r12). data/game/schema_fingerprints.json records every table's row-count/row-size/hash; re-extraction diffs against it so a future patch that adds, moves, or resizes columns fails loudly instead of serving silently-wrong data. See docs/GAME_DATA_RESEARCH.md for the reverse-engineered file format and extraction methodology.

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Architecture

poe2-mcp/
├── launch.py              # Entry point
├── src/
│   ├── mcp_server.py      # Main MCP server (38 tools registered)
│   ├── api/               # External API clients
│   │   ├── poe_ninja_api.py
│   │   ├── character_fetcher.py
│   │   └── rate_limiter.py
│   ├── analyzer/          # Analysis components
│   │   ├── character_analyzer.py
│   │   └── weakness_detector.py
│   ├── calculator/        # Numeric calculations
│   │   ├── ehp_calculator.py
│   │   ├── spirit_calculator.py
│   │   └── stun_calculator.py
│   ├── data/              # Data providers
│   │   ├── mod_data_provider.py
│   │   └── fresh_data_provider.py
│   ├── optimizer/         # Optimization engines
│   │   ├── gear_optimizer.py
│   │   └── gem_synergy_calculator.py
│   ├── parsers/           # Data parsers
│   │   ├── passive_tree_resolver.py
│   │   └── specifications/  # Datc64 format specifications
│   ├── knowledge/         # Game mechanics knowledge base
│   │   └── poe2_mechanics.py
│   └── database/          # SQLite database
│       ├── models.py
│       └── manager.py
├── data/                  # Game data files
│   ├── psg_passive_nodes.json
│   ├── poe2_support_gems_database.json
│   └── poe2_mods_extracted.json
└── tests/                 # Test suite

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Development

Running Tests

pytest tests/ -v

Running the Server Directly

# If installed via pip
poe2-mcp

# From source
python launch.py

Key Files

• src/mcp_server.py - MCP server with 38 registered tools
• src/data/mod_data_provider.py - Item mod data access layer
• src/calculator/ehp_calculator.py - EHP calculations
• src/optimizer/gem_synergy_calculator.py - Support gem logic
• data/psg_passive_nodes.json - Passive tree database
• data/poe2_mods_extracted.json - Item modifier database (14,269 mods)

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Troubleshooting

"Server not found" in Claude Desktop

• Check the path in config is absolute (not relative)
• Ensure Python is in your PATH
• Try running python launch.py manually to see errors

"No character found"

• Your character must be on poe.ninja (public ladder)
• Character name is case-sensitive
• Try the full poe.ninja URL with import_poe_ninja_url

Tools return empty results

• Database may need initialization: python launch.py handles this
• Check data/ directory exists with JSON files

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Credits

Data sources:

• poe.ninja - Character data and builds
• Path of Building (PoE2) - Skill data
• Path of Grinding - Passive tree data

MCP Protocol:

• Model Context Protocol
• mcpb Bundle Format

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License

MIT License - See LICENSE for details.

This is a community project. Not affiliated with Grinding Gear Games.

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