LegacyMCP

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Active Directory MCP Server for AI-powered assessment

LegacyMCP brings the power of AI to Active Directory on-premises environments. It exposes AD data as tools that Claude and other LLMs can query directly — turning a static assessment script into an interactive, intelligent conversation with your infrastructure.

No more 200-page Word documents that nobody reads. Ask questions, get answers, understand your AD.

Why LegacyMCP

Active Directory is still the backbone of most enterprise environments. Despite the cloud push, AD on-prem is very much alive — and largely invisible to modern AI tooling.

LegacyMCP fills that gap.

It was born out of a real consulting need: the Identity team at Impresoft 4ward runs AD assessments for enterprise clients regularly. The goal was to make that process faster, smarter, and more useful — and to share the result with the community.

Two modes, one interface

Live Mode Connects directly to Domain Controllers via WinRM and PowerShell. Real-time data, ideal for internal admins or consultants with direct network access.

flowchart LR
    A[LegacyMCP Server] -->|WinRM read-only| B[Active Directory]
    A -->|SQLite in-memory| C[MCP Tools]
    C -->|Natural language| D[Claude / Copilot]

Offline Mode A PowerShell collector exports AD data to a structured JSON file. The MCP server loads and queries that data locally — no network access required during analysis. Perfect for remote consulting scenarios.

flowchart LR
    A[PowerShell Collector] -->|JSON file| B[LegacyMCP Server]
    B -->|SQLite in-memory| C[MCP Tools]
    C -->|Natural language| D[Claude / Copilot]
    E[Active Directory] -.->|read-only collection| A

Multi-scope Workspace

LegacyMCP understands that real-world assessments are rarely simple:

• Single domain — limited access, no Enterprise Admin required
• Full forest — global view across all domains in the forest
• Multiple forests — separate environments, independent analysis
• Migration scenarios — source/destination mapping, SIDHistory tracking,

naming conflict detection

What it covers

LegacyMCP Core covers everything in Carl Webster's legendary ADDS_Inventory script (https://github.com/CarlWebster/Active-Directory-V3) — now queryable via natural language:

• Forest and domain configuration
• Optional AD features (Recycle Bin, etc.)
• AD Schema — custom objects and attributes
• Domain Controllers, FSMO roles, local settings (NTP, registry)
• Event Log configuration per DC
• SYSVOL state and replication
• Sites, site links, replication topology
• Users — counts, states, privileged accounts
• Groups — privileged groups, nested membership
• Organizational Units — full OU tree
• GPO Inventory — list, OU links, blocked inheritance
• Trust relationships — type, direction, SIDHistory
• Fine-Grained Password Policies
• DNS configuration on Domain Controllers
• PKI / CA Discovery — Certification Authorities from AD

Enterprise layer

Impresoft 4ward maintains a proprietary enterprise layer on top of LegacyMCP Core:

• DHCP Analysis — DHCP infrastructure assessment
• GPO Analysis — deep Group Policy analysis
• AD Security Analysis — security posture assessment
• AD Health Check — misconfiguration and operational health review
• PKI Configuration Analysis — CA infrastructure and certificate template review
• PKI Security Analysis — PKI security assessment
• ESC Analysis — certificate template vulnerability assessment
• DOCX generation — automated assessment documents from corporate templates

Interested? Get in touch.

Security by Design

LegacyMCP is built around ten security principles that apply across every deployment scenario:

1. Read-only by design — LegacyMCP never creates, modifies, or deletes any AD object. This is an architectural decision, not a limitation.

1. Least privilege — the tool operates with the minimum rights required. In Offline Mode, no live AD credentials are needed at all.

1. Sensitive data stays local — in Offline Mode, AD data never leaves the client network toward the cloud. Analysis happens locally. JSON output files are classified Confidential/Restricted.

1. Strong authentication for exposed endpoints — four deployment profiles with increasing security requirements: local-only, internal network (API Key), internal network with Entra ID, and internet-facing with WAF and OAuth2/OIDC.

flowchart TD
    A[Profile A - Local] -->|localhost only| B[LegacyMCP Server]
    C[Profile B-core - Internal] -->|HTTPS + API Key| B
    D[Profile B-enterprise - Internal] -->|HTTPS + Entra ID| B
    E[Profile C - Internet] -->|WAF + OAuth2/OIDC + MFA| F[Azure APIM]
    F --> B

1. TLS on all non-localhost endpoints — no plaintext traffic outside localhost under any deployment profile.

1. Credentials never in plaintext — gMSA for service accounts, Azure Key Vault for enterprise deployments, DPAPI user-scope encryption for explicit credentials on client machines. Never in config files, environment variables, or logs.

1. Code integrity — signed PowerShell collector, signed executable releases, published SHA256 hashes for all release artifacts.

1. Full auditability — dedicated Windows EventLog, every operation logged with who requested what, when, and on which objects. SIEM and Sentinel compatible.

1. Unified data format — Live Mode snapshots and Offline Mode JSON files share the same format, enabling temporal comparisons and full interoperability between modes.

1. Safe degradation — partial data is always explicit. Unreachable domain controllers are flagged, never silently skipped.

See DISCLAIMER.md for terms of use.

Built for enterprise environments

• gMSA support — no password management headaches
• Windows Service — install, forget, monitor
• Dedicated EventLog — full audit trail, SIEM-ready
• Performance Counters — heartbeat and DC reachability monitoring (roadmap)
• Graceful degradation — partial data is better than no data
• Four deployment profiles — local offline, internal network with API Key,

internal network with Entra ID, internet-facing with WAF

Requirements

LegacyMCP involves three distinct machines with different requirements:

Collector machine — runs the PowerShell data collection script:

• Windows 10 / Windows Server 2012 R2 or later
• PowerShell 5.1+
• ActiveDirectory module (RSAT)
• Minimum AD permissions as documented in docs/minimum-permissions.md.

Dedicated scripts in installer/ are available to apply, test, and remove them. Domain Admin is not required.

MCP server machine — runs the LegacyMCP Python server:

• Profile A: the consultant's own machine (same as collector machine above)
• Profile B-core: a dedicated Windows Server 2016+ (2012 R2 supported),

domain-joined, with a service account

• Python 3.10+

Consultant machine — runs Claude Desktop:

• Claude Desktop with Pro plan
• Node.js 18+ — Profile B-core only, required for mcp-remote

Getting Started

New to LegacyMCP? Start here:

👉 Getting Started Guide

Already know which profile you need?

• Profile A — local offline setup
• Profile B-core — LAN endpoint with HTTPS

Further Reading

• Deployment profiles
• Architecture
• Setup Reference — all parameters for Setup-LegacyMCP.ps1
• TLS certificate setup
• Design principles
• MCP Tools Reference

Author

Marco Lelli Head of Identity — Impresoft 4ward Microsoft Identity specialist with 25+ years in enterprise IT infrastructure.

📖 Follow the build story on Legacy Things — a technical blog about the legacy mechanisms that still run the world.

License

MIT — free to use, modify, and distribute. See LICENSE for details.