Minerva MCP Server

Minerva MCP

Microsoft 365 and Azure administration for AI assistants — including the parts Microsoft Graph cannot reach.

An MCP server that lets Claude, Copilot, VS Code or any MCP client query and administer a Microsoft 365 tenant in plain language.

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Why another Microsoft 365 MCP server?

There are already good ones, and this is not trying to replace them.

If you only need Graph, use Lokka or ms-365-mcp-server. They are excellent, more mature, and more widely used. Lokka in particular is written by a Microsoft Entra product manager.

Reach for this one when you hit the wall everyone hits eventually: a large part of Microsoft 365 administration has no Graph API. Mailbox permissions, transport rules, message trace, retention policies, sensitivity labels, Teams calling policies, SharePoint term stores, tenant-wide Exchange settings — those live in PowerShell and nowhere else. This server exposes them, with a risk classification and a confirmation step in front of anything that writes.

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How it fits together

flowchart LR
    A["AI client<br/>Claude · VS Code · Copilot Studio"]
    B["minerva-mcp"]
    C{"Risk<br/>classifier"}
    D["Human<br/>confirmation"]
    G["Microsoft Graph<br/>Azure ARM · Search"]
    P["PowerShell 7<br/>Exchange · PnP · Teams · Purview"]
    M["Microsoft<br/>authorizes the token"]

    A -->|"stdio or HTTP"| B
    B --> C
    C -->|"read"| G
    C -->|"write"| D
    D -->|"signed mandate"| G
    D -->|"signed mandate"| P
    C -->|"read"| P
    G --> M
    P --> M

Reads go straight through. Writes stop at a classifier, come back to you as an input_required describing the action and its consequences, and only run once you confirm. Microsoft still has the final word: the server forwards a token, it never grants access.

Install

Nothing to clone. Add it to your client and sign in on first use.

Claude Desktop

claude_desktop_config.json:

{
  "mcpServers": {
    "minerva": {
      "command": "npx",
      "args": ["-y", "minerva-mcp", "--stdio"]
    }
  }
}

VS Code

.vscode/mcp.json:

{
  "servers": {
    "minerva": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "minerva-mcp", "--stdio"]
    }
  }
}

More, including read-only and app-only setups, in examples/.

On the first tool call the server prints a device-code prompt on stderr: open the link, enter the code, done. No app registration needed to try it — it uses the public Microsoft Graph PowerShell client by default.

Requirements: Node.js 20+. For the PowerShell tools, PowerShell 7+ and the modules you intend to use (ExchangeOnlineManagement, PnP.PowerShell, MicrosoftTeams).

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What you can ask

"Which mailboxes have full access delegated to someone outside their department?" → execute_exchange_online with Get-MailboxPermission, no Graph equivalent exists.

"Show me every conditional access policy that does not require MFA, and our Secure Score." → generate_security_report + microsoft_graph_call.

"Create a shared mailbox for invoicing and give the finance team access." → classified as a write: the server describes the action and its consequences, and waits for your confirmation before doing anything.

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Tools

Restrict the surface with --tools=microsoft_graph_call,get_tenant_context, or forbid every write with --read-only.

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Approval, and why it is not optional

A model reads untrusted content — an email subject, a site name, a document — and decides which tool to call. Prompt injection is not hypothetical, and the tools here can delete mailboxes.

So writes do not simply execute. Every action is classified auto, confirmed or critical from the HTTP verb and path (or the PowerShell verb). Anything above auto makes the server answer input_required under MCP's Multi Round-Trip Requests: your client shows what is about to happen and its consequences, you confirm, and only then does it run.

The confirmation is a signed mandate (HMAC) bound to the caller, the method, and a digest of the arguments, valid five minutes. A mandate obtained to delete /users/1 cannot be replayed on /users/999, and cannot be presented by anyone else.

If your client does not support elicitation, nothing is silently executed: the server returns an error saying the action needs confirmation.

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Options

Every flag has an environment variable equivalent.

Transport

In stdio mode all logs go to stderr — stdout belongs to the protocol.

Authentication

Defaults: bearer over HTTP (the caller supplies the token), device-code over stdio, client-secret as soon as a secret is present. Each resource gets its own token: Graph, ARM, Exchange, Purview, SharePoint and Teams do not share an audience.

Scope

--read-only reuses the same risk classifier as the approval gate, so it covers PowerShell cmdlets too, not just HTTP verbs.

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Protocol support

Speaks MCP 2026-07-28, and still serves handshake-era clients until 2027-07-28.

One endpoint serves both generations; the request body decides which. Both read the same tool registry, and a test compares them against a frozen contract so they cannot drift.

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Security

Read SECURITY.md before deploying. The three things that matter:

1. This server grants nothing. It forwards a Microsoft token; Microsoft authorizes. A restricted token gives a restricted server.
2. Graph tokens cannot be verified by a third party — they carry a nonce header that only Graph can check. Their tid/oid claims are therefore self-reported. The server validates them structurally, flags them verified: false, and binds approval mandates to a fingerprint of the token itself rather than to the claims alone. A token that should have verified and did not is rejected.
3. Local PowerShell mode isolates nothing. Cmdlets run with the current user's rights. Do not expose it to a caller you do not trust.

Cmdlet names and parameters never reach the script as code: they travel through environment variables, the name is validated against a strict Verb-Noun pattern, and the call goes through Get-Command plus the call operator.

Report a vulnerability privately — see SECURITY.md.

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What this does not do

• No process isolation in local mode.
• No multi-tenant brokering — one server, one identity.
• No signed audit ledger. Audit events are JSON on stderr, not a signed, offline-verifiable record.

Those three belong to Minerva-IA, the commercial platform this server was extracted from. Everything in this repository works without it.

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Development

npm install
npm run dev:stdio     # stdio, hot reload
npm run verify        # typecheck + tests + secret scan
npm run build && node scripts/smoke-stdio.mjs

Tests need no credentials and touch no network.

Pull requests are closed until 2027-07-31 — see CONTRIBUTING.md for why, and for what is welcome in the meantime (bug reports very much are).

Licence

MIT — see LICENSE.