Skills/npm/microsoft365-mcp-server

microsoft365-mcp-server@1.3.1

VERIFIED· not started

Publisher claims: "A Model Context Protocol (MCP) server for Microsoft 365 - manage mail, calendar, contacts, files, Teams, Planner, OneNote, To Do, and more via Microsoft Graph." Observed in sandbox: no network, touches nothing outside the project, writes no memory.

Registry npm (MCP server)Publisher sapientsai · publishing for 229 daysInstalls 2,483Last detonated 5d ago
$claude mcp add microsoft365-mcp-server -- npx -y microsoft365-mcp-server
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Coverage

Not started: dependency install failed; the server itself was not observed.
Tested
the dependency install step · every file read, file written and host contacted by what ran
Not tested
server startup · the tool list · tool behavior

What this means for the label: Verified here covers what ran. The server's tools were not exercised with a real credential, so nothing about their behavior is asserted; the credential summary below says what to do with that.

Before you give it your token

It will ask for
MS365_ACCESS_TOKENMS365_AUTH_MODEMS365_CERT_PASSWORDMS365_CLIENT_SECRETMS365_JWT_SIGNING_KEYMS365_OAUTH_BASE_URLMS365_TOKEN_CACHEMS365_TOKEN_CACHE_PATHMS365_TOKEN_ENCRYPTION_KEYMS365_UPLOAD_TOKENTOKEN_STORAGE_PATHConfiguration, not credentials: FASTMCP_HOST, GIT_HASH, MCP_STATELESS, MS365_ALLOWED_MAILBOXES, MS365_ALLOWED_REDIRECT_URI_PATTERNS, MS365_CERT_PATH, MS365_CLIENT_ID, MS365_DISABLE_SIGN_IN, MS365_ENABLED_TOOLS, MS365_EXTRA_SCOPES, MS365_GRAPH_CIRCUIT_DISABLED, MS365_GRAPH_VERSION, MS365_MAX_EXTRACT_BYTES, MS365_ORG_MODE, MS365_PRESETS, MS365_PUBLIC_BASE_URL, MS365_READ_ONLY, MS365_REDIRECT_URI, MS365_REQUIRE_DRAFT, MS365_TENANT_ID, MS365_USE_DEVICE_CODE, MS365_WIDEN_SCOPES_ON_REFRESH, TRANSPORT_TYPE
Where it talks to
no vendor host named in the codeAlso microsoft.com, claude.ai, claude.com — not the publisher's domain; check what for before connecting.
What the honeypot saw
no credential files read · no network
What we could not test
server startup · the tool list · tool behavior

Connect it with a scoped credential, under the guard, and read the third-party hosts first. The code names microsoft.com, claude.ai, claude.com as well as its own vendor. The guard injects MS365_ACCESS_TOKEN, MS365_AUTH_MODE, MS365_CERT_PASSWORD, MS365_CLIENT_SECRET, MS365_JWT_SIGNING_KEY, MS365_OAUTH_BASE_URL, MS365_TOKEN_CACHE, MS365_TOKEN_CACHE_PATH, MS365_TOKEN_ENCRYPTION_KEY, MS365_UPLOAD_TOKEN, TOKEN_STORAGE_PATH only into requests to the host you bind (and its subdomains) and refuses the rest.

$vet-skills run --net declared -- npx -y microsoft365-mcp-server

Never paste a credential into a chat, a ticket or a report, including ours. How the guard holds it.

Is [email protected] safe to install?

KillerSkills ran it in the KillerSkills honeypot sandbox (2 scenarios; not started: dependency install failed; the server itself was not observed) on 2026-11-09 and scored it 90/100 (Verified). In what ran, nothing we could detect went wrong: no undeclared network egress, no credential reads, no persistent instruction writes. What it does with a real credential was not observed; the static findings and the publisher carry the rest of the score. Summary: no network, touches nothing outside the project, writes no memory.

Behavior trace

Honeypot run · 2 s · 2 scenarios · 0 deviations
t+CategoryObserved action
0.0sprocessno install scripts in bundle
1.8sprocessdependency install exit 1 · npm error code EUNSUPPORTEDPROTOCOL npm error Unsupported URL Type "workspace:": workspace:* npm error A complete log of this run can be found in: /tmp/ks-detonate-YEbqyK/task/home/.npm/_logs/2026-11-09T18_35_03_233Z-debug-0.log
1.8sclaimednot started: dependency install failed (exit 1); the server itself was not observed
1.9sprocessscript backend runs setup only
1.9sprocessno install scripts to re-run

Static findings

HIGH
Access to sensitive file pathsdist/index.js:664 · Access to sensitive file paths — SSH keys, AWS credentials, env files, or system filesconst loadEnvFileIfPresent = (path = ".env") => {Fix: Stop enumerating or reading credential locations; take secrets from a declared environment variable the user sets on purpose.
AST05
MEDIUM
npx invocation of non-well-known packagepackage.json:43 · npx invocation of non-well-known package — may execute untrusted code"start": "pnpm build && npx microsoft365-mcp-server",Fix: Pin versions and sources; vendor anything fetched at install time.
AST06

Cost to the agent

Instructions loaded
≈81 tok
1 file · 10 in bundle
Tool list per prompt
≈0 tok
0 tools · 0 per tool
Handshake
no reply
launch to tools/list, stdio
Undocumented tools
0
description under 20 chars · avg 0

Tokens estimated at four characters each. The tool list is re-read by the agent on every turn, so it is the number to compare between servers that do the same job: ranked across the index.

Known vulnerabilities

No advisories in OSV for microsoft365-mcp-server@1.3.1 as of 5d ago. This is the package itself, not its dependencies.