outlook-mcp
This MCP server provides comprehensive access to on-premises Microsoft Exchange via EWS for managing email, calendar, contacts, folders, and availability data.
Email: List, search, read, send, reply, forward, move, copy, delete, and mark emails; create and send drafts; download attachments.
Folders: List and create mailbox folders.
Calendar: List, get, create, update, and delete events; respond to meeting invites; find free time slots; get personal availability; list calendars.
Contacts: Search (personal and GAL), get, create, update, and delete contacts.
System: Test connectivity (ping) and retrieve mailbox metadata.
The server is distributed as a PyPI package named outlook-ews-mcp.
Click on "Install Server".
Wait a few minutes for the server to deploy. Once ready, it will show a "Started" state.
In the chat, type
@followed by the MCP server name and your instructions, e.g., "@outlook-mcpfind my unread emails from last week"
That's it! The server will respond to your query, and you can continue using it as needed.
Here is a step-by-step guide with screenshots.
outlook-ews-mcp
outlook-ews-mcp is an MCP server for on-prem Microsoft
Exchange via EWS (exchangelib). It gives
MCP-compatible clients (Claude Desktop, Claude Code, and any other MCP client) access to
email, calendar, contacts, folders, attachments, and availability data through a single,
testable Python service — no direct mailbox scripting required.
Renamed from
outlook-mcp. That name was already taken on PyPI by an unrelated project, so the distribution and CLI name are nowoutlook-ews-mcp. The Python import path is unchanged. Until the first tagged PyPI release, install from this repository as shown below.
Contents
Related MCP server: owa-mail-mcp
Highlights
Email — list, search (substring or Advanced Query Syntax), read, send, reply, forward, move, copy, delete, mark, categorize, bulk actions, raw MIME export, attachment add/delete
System — Inbox Rules, Out-of-Office (automatic replies), read-only delegate listing
Calendar — list, create, update, delete, respond to invites, find free slots, view a shared/delegate mailbox's calendar, Room Finder, bulk actions
Contacts — search, read, create, update, delete
Folders & attachments — folder CRUD and attachment download
Auth —
NTLMandBasicagainst on-prem ExchangeTransport —
stdioandSSEArchitecture — centralized error mapping through a single
ExchangeClientabstraction (see Project notes)Safety — a privacy-safer smoke check by default (see Smoke check)
Ops — Docker image plus GitHub and GitLab CI/CD pipelines included
Tool catalog
Every tool below is registered in tool_specs.py, the
single source of truth for its name, description, and schema. Read-only marks tools
that never modify the mailbox — they get more concurrency (see
Request queue) and are safe to call speculatively.
System
Tool | Description | Read-only |
| Check connectivity to Exchange | ✅ |
| Get mailbox metadata | ✅ |
| List mailbox delegates and their folder permission levels — read-only because | ✅ |
| List server-side inbox rules | ✅ |
| Create a server-side inbox rule, e.g. "from this sender → move to folder" | |
| Enable/disable a rule or change its priority (other fields aren't updatable here) | |
| Delete a server-side inbox rule by id | |
| Get the out-of-office (automatic reply) settings | ✅ |
| Turn automatic replies off, on, or schedule a start/end window |
⚠️
create_inbox_rule/update_inbox_rule/delete_inbox_rulemanage rules over EWS, which removes the client-side rule blob desktop Outlook keeps — this can wipe rules a user created in Outlook itself. This is documented EWS behavior, not a bug here.
Tool | Description | Read-only |
| List emails in a folder | ✅ |
| Get a full email by id | ✅ |
| Export a message's raw RFC 822 MIME content, base64-encoded | ✅ |
| Get every message of a conversation in order, bodies included | ✅ |
| Search by substring (subject/body/sender) or server-side Advanced Query Syntax | ✅ |
| Send a new email | |
| Reply to an email | |
| Forward an email | |
| Move an email to another folder | |
| Copy an email to another folder | |
| Bulk move, with per-item results — one bad id doesn't fail the rest | |
| Bulk copy, with per-item results | |
| Bulk delete, with per-item results (soft-deletes unless | |
| Delete an email | |
| Update read state, importance, or the follow-up flag | |
| Set, add, or remove Outlook categories (the coloured labels) | |
| Bulk version of | |
| Bulk version of | |
| List categories in use with counts, sampled from recent messages (not the mailbox master category list) | ✅ |
| List mailbox folders | ✅ |
| Create a mailbox folder | |
| Rename a folder — refuses built-in folders (Inbox, Sent Items, Calendar, ...) | |
| Delete a folder and everything in it — refuses built-in folders | |
| Create an email draft | |
| Update a draft; omitted fields are left unchanged, | |
| Send an existing draft | |
| Attach a local file to a message, typically a draft — the file must live under | |
| Remove one attachment from a message by id | |
| Save an attachment to disk | ✅ |
Calendar
Tool | Description | Read-only |
| List calendar events in a time range; pass | ✅ |
| Get a calendar event by id; pass | ✅ |
| Create a calendar event | |
| Update a calendar event | |
| Delete a calendar event | |
| Accept, decline, or tentatively respond to an invite | |
| Find open meeting time slots | ✅ |
| Bulk delete events, with per-item results | |
| Bulk respond to invites, with per-item results | |
| Get free/busy slots; pass | ✅ |
| List calendars | ✅ |
| List Room Finder room lists (groups of meeting rooms) | ✅ |
| List the meeting rooms in a Room Finder room list | ✅ |
Contacts
Tool | Description | Read-only |
| Search contacts | ✅ |
| Get a contact by id | ✅ |
| Create a personal contact | |
| Update a personal contact | |
| Delete a personal contact |
Typical use cases
Connect Claude Desktop or another MCP client to on-prem Exchange
Search inbox messages and fetch full email content
Send or draft emails from AI workflows
Inspect calendars and create meetings
Check free/busy windows for scheduling
Search personal contacts or the Global Address List
Expose Exchange operations through a controlled MCP boundary instead of direct mailbox scripting
Security notes
What the current code does:
Scoped connectivity | Connects only to the Exchange/EWS endpoint configured in |
No telemetry | Contains no telemetry, analytics, or third-party data export logic |
Secrets stay local | Keeps secrets in environment variables / |
Clean error payloads | Structured MCP error responses never include raw Exchange exception text, message bodies, attachment contents, or passwords; successful tools return only the mailbox data they were asked for |
Clean logs |
|
Clean Docker builds |
|
What you should still be careful with:
EXCHANGE_VERIFY_SSL=falsedisables TLS certificate verification — trusted internal/self-signed environments only.EXCHANGE_AUTH_TYPE=Basicsends credentials in the clear, so the server refuses to start against anhttp://EXCHANGE_SERVER; only override withEXCHANGE_ALLOW_INSECURE_BASIC_AUTH=truefor a local/test server you control.get_attachmentwrites files to disk, andsend_email/reply_email/forward_email/create_draftread local files (viaattachments) and attach their contents to outgoing mail. Combined with untrusted email content, this is a plausible path for prompt-injected exfiltration of any file readable by the process. Local file access is refused by default and only works onceEXCHANGE_ATTACHMENT_ROOTis set to an absolute directory, which then confines bothattachmentspaths andget_attachment'ssave_pathto that directory tree (an unsetsave_pathstill falls back to the system temp directory).outlook-ews-mcp-smokeis privacy-safe by default and prints only masked mailbox info plus counts; setOUTLOOK_MCP_SMOKE_INCLUDE_DATA=trueonly if you explicitly want real inbox/event data in stdout.If you enable file logging with
LOG_FILE, protect that file with OS permissions.If you publish Docker images from CI, protect GitLab/GitHub project access and registry permissions.
Quick start
uv venv
source .venv/bin/activate
uv pip install -e .[dev]
cp .env.example .env
outlook-ews-mcpBy default the server runs in stdio mode. Set MCP_TRANSPORT=sse to start an HTTP
server instead.
Configuration
Minimal .env to get started — everything else below has a working default:
EXCHANGE_SERVER=https://mail.company.com/EWS/Exchange.asmx
EXCHANGE_USERNAME=DOMAIN\username
EXCHANGE_PASSWORD=secret
EXCHANGE_EMAIL_ADDRESS=user@company.com
EXCHANGE_AUTH_TYPE=NTLMA fully commented copy of every variable lives in .env.example.
Variable | Default | Description |
| (required) | EWS endpoint URL, e.g. |
| (required) |
|
| (required) | Account password |
| unset | SMTP address; set when |
|
|
|
|
| Allow |
|
| Verify the server's TLS certificate; |
| unset (auto-detected) | Exchange server version, e.g. |
|
| Used only when Exchange reports an unresolvable GUID timezone id; normal operations use the mailbox's own default timezone |
|
| Per-request timeout in seconds (1–300) |
|
| Wall-clock retry budget for read-only calls when Exchange reports itself busy, not a retry count; |
| unset | Mailbox to impersonate (requires Exchange impersonation permissions) |
|
| Max size per attachment, enforced on both upload and |
|
| Max attachments on a single send/reply/forward/create_draft call (1–100) |
|
| Max combined attachment size on a single call (1–500) |
| unset (disabled) | Directory that confines attachment paths. Unset refuses all local file access for |
|
| Cap on |
|
| Cap on raw MIME export size before base64 expansion (1–100) |
| unset | Appended to outgoing text bodies and replies/forwards. No EWS signature API exists, so this is configuration, not the mailbox's Outlook signature |
| unset | Appended to outgoing HTML bodies. Same caveat as above; no cross-conversion between the two. Either can be skipped per call with |
|
|
|
|
| Bind host when |
|
| Bind port when |
|
| Concurrent read-only tool calls (1–8); mutating calls always run exclusively. See Request queue |
|
| Max calls admitted at once, running + waiting (1–1000); beyond that, calls get an immediate |
|
|
|
| unset (stderr) | Log file path; protect it with OS permissions if set |
Behavior notes that aren't tied to a single variable:
list_eventsandfind_free_slotsaccept a boundedlimit(default 200, maximum 1000); event ranges are capped at 366 days and free-slot ranges at 31 days, so broad queries can't produce unbounded EWS or MCP responses.Listings stay lean by design: email summaries carry the sender but not recipient lists (
get_emailhas them),list_eventsreturns events without bodies (get_eventhas them), andget_emailreturns RFC-822 headers only withinclude_headers: true.Send operations return
id: nullwhen EWS doesn't provide a durable id for the sent copy (notably replies, forwards, and sent drafts).Attachment metadata includes
downloadable; embedded Exchange item attachments havedownloadable: falseand can't be saved byget_attachment.
Request queue
Clients issue several tool calls in parallel. Exchange work is blocking, so the server runs it in worker threads and admits calls through one shared FIFO queue.
MCP_MAX_CONCURRENCY(default4) sets how many read-only calls run at once, so an agent asking for an email, the folder list, and the calendar pays the slowest round trip instead of the sum. Mutating calls always run exclusively — one at a time, never overlapping a read — so read/write races on shared account state can't happen. Callers beyond the limit wait their turn, served in arrival order; a waiting mutation blocks later reads from overtaking it.MCP_MAX_QUEUE_SIZE(default20) caps how many calls can be admitted at once, running or waiting. Once that many are already in, further calls get an immediateserver_busyerror instead of joining an unbounded queue.The transport stays responsive while work is in flight. Tools are awaited rather than run on the event loop thread, so finished responses go out immediately and pings are answered while a long call is still running.
There is no per-call timeout, deliberately. A thread blocked on a socket read can't be killed from outside; the runtime can only stop waiting for it, which abandons the thread along with the EWS session it holds.
exchangelib's session pool has a hard maximum and hands out sessions in a loop with no give-up path, so leaked sessions eventually starve it and every later call blocks forever. A slow call is waited out instead, bounded byEXCHANGE_TIMEOUTplusEXCHANGE_MAX_RETRY_WAIT_SECONDS: the account's retry policy is fail-fast, so every EWS call raises on its first transient error rather thanexchangelibretrying it forever internally, andExchangeClientretries only read-only calls itself, bounded by that wall-clock budget. Writes are never auto-retried. Overruns past the expected budget are logged.
Claude Desktop example
{
"mcpServers": {
"outlook": {
"command": "outlook-ews-mcp",
"env": {
"EXCHANGE_SERVER": "https://mail.company.com/EWS/Exchange.asmx",
"EXCHANGE_USERNAME": "DOMAIN\\username",
"EXCHANGE_PASSWORD": "secret",
"EXCHANGE_EMAIL_ADDRESS": "user@company.com",
"EXCHANGE_AUTH_TYPE": "NTLM"
}
}
}
}Smoke check
After filling in .env, run:
outlook-ews-mcp-smokeDefault output is sanitized for safer verification. If you intentionally want sample mailbox/event data in the output:
OUTLOOK_MCP_SMOKE_INCLUDE_DATA=true outlook-ews-mcp-smokeDocker
docker build -t outlook-ews-mcp .
docker run --rm --env-file .env outlook-ews-mcpCI/CD
GitHub Actions and GitLab CI both run lint, formatting, type checks, tests, dependency
audit, and package builds, using the uv version pinned in pyproject.toml.
GitHub | Additionally publishes tagged releases ( |
GitLab | Additionally builds and pushes a Docker image to the GitLab Container Registry on the default branch and on tags, using the built-in |
Default image tagging behavior:
Trigger | Tags pushed |
Default branch |
|
Git tag |
|
Development
uv run --python 3.12 --with '.[dev]' ruff check .
uv run --python 3.12 --with '.[dev]' pytest -qProject notes
The implementation is centered around a single
ExchangeClientabstraction so auth, transport, retries, and error mapping stay centralized.Errors are returned in a structured JSON form suitable for MCP
isError=truehandling.
Contributing
Bug reports and PRs are welcome — see CONTRIBUTING.md for how to set up a dev environment and run the test suite without a real Exchange server. For vulnerability reports, see SECURITY.md.
License
MIT — see LICENSE.
Maintenance
Resources
Unclaimed servers have limited discoverability.
Looking for Admin?
If you are the server author, to access and configure the admin panel.
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