Model Context Protocol (MCP) support

Feature request
1

Hi eM Client team,
I’d like to request support for the Model Context Protocol (MCP) in eM Client.

MCP is an open standard developed by Anthropic for connecting AI assistants to external tools (email, calendars, CRMs, etc.) in a secure and structured way. It allows an AI client to call well‑defined “tools” exposed by an MCP server instead of screen‑scraping or ad‑hoc APIs. More about it here: https://modelcontextprotocol.io

It’s already being adopted by several AI clients and tools, and there are reference implementations and documentation here:

Why this would be valuable for eM Client:

  • Allow AI assistants (desktop and cloud) to safely read, search, and act on email and calendar data via a standard protocol, instead of custom integrations. blog.modelcontextprotocol
  • Make it possible to build MCP servers around eM Client data or to let eM Client act directly as an MCP client for external tools (e.g., CRM, ticketing, knowledge bases). blog.modelcontextprotocol
  • Attract power users who are already building MCP‑based workflows and want to keep eM Client as their primary mail app.

From a product perspective, even a minimal MCP implementation (read‑only access to messages, search, and sending via a small set of tools) would already be very useful.

Could you please let me know:

  1. Whether MCP support is on your roadmap or under consideration.
  2. If there is a preferred channel (beta program, GitHub, etc.) where technically inclined users could help test or provide concrete use‑cases.

Thanks a lot for considering this – I think eM Client could be a great first‑class unit in the emerging MCP ecosystem.

Thanks, best…

7 Likes
2

I’d like to request support for the Model Context Protocol (MCP) in eM Client

Suggest you create a Sleekplan suggestion for MCP for others to vote on via the above link.

Whether MCP support is on your roadmap or under consideration.

This is the current Sleekplan suggestion Roadmap. Apart from that official support might comment.

Why this would be valuable for eM Client:
Allow AI assistants (desktop and cloud) to safely read, search, and act on email and calendar data via a standard protocol, instead of custom integrations.

MCP might then be a privacy / security / dangerous issue controlling and accessing all your email etc if it’s like OpenClaw AI assistant. I’d be worried if it is.

Eg: There was a recent incident where Cursor, an AI agent powered by Anthropic’s Claude Opus 4.6 model deleted an entire database including the backup which was devastating for the business.

2 Likes
3

MCP support is planned for version 11

7 Likes
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Thanks for the info.
Would that be local support or remote MCP server?
Is there a release date for the v11?

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It is partially covered in the AppleScript support ticket that is already in the Roadmap and as @Michal_Burger mentioned I wil wait for the v11. I am honestly curious for the remote MCP server/cloud support.

Agreed. But anything can be a security issue in case you either underestimate it or use unwisely. I use Perplexity and its “Computer” solution for work mostly and have been going without issues while having most of my workspace(s) connected to AI. I admit to say I am very cautious in automation though.

1 Like
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I’ve been using OpenClaw to manage a couple of email accounts that are also visible in eM Client. That way my agent can create an email, place it in the Drafts folder, I can review it in eM Client, and then send it. It actually works quite well. OpenClaw can also analyze emails that I move into a designated folder and then draft replies—for example, unsubscribe requests. There are commercial programs like Fixr that offer similar features. Even though emclient doesn’t have an API, I’m still able to do quite a lot with it.

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As eM Client is a locally ran software and we do not route emails via cloud (unlike MS Outlook New, Spark, Superhuman or others) the MCP server will run locally as well. Of course you can set up your network to access a local MCP server remotely.

3 Likes
8

how long before we see MCP feature, this is necessary, and I hope there isn’t some paywall like there was with the Ai junk you guys previously added into the client.

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@zerocool

how long before we see MCP feature, this is necessary.

As @Michal_Burger advised further up this thread MCP support is planned for V11. No doubt like with previous major releases, that will be announced via the official blog page and forum announcement page as per below links. So keep checking those for updates when it’s released.

https://www.emclient.com/blog

https://forum.emclient.com/c/announcement

I hope there isn’t some paywall like there was with the Ai junk you guys previously added into the client.

If you purchase eM Client as a yearly subscription the AI Addon “its included” as per the pricing page. Otherwise it’s optional and not mandatory.

The AI ChatGPT Addon is not junk and many users are very happy with the AI Addon. Seemed to work ok when I tested it previously. There is also a new AI Summarise feature coming in V11.

So If you are currently using the AI Addon and have problems, then suggest you create a new thread and state exact what the issues are and others who use the AI Addon might be able to assist you.

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MCP Support now in the new eM Client 11 Beta

Model Context Protocol (MCP) support

Connect your AI agent to eM Client to find accounts and folders, search and retrieve emails or conversations, perform selected mailbox actions, draft and send messages, and more!

Automatic setup or configuration instructions are available for ChatGPT, Codex CLI, Copilot App, Copilot CLI, Claude Code, Antigravity CL, Claude App, LM Studio, AnythingLLM, OpenClaw, but any tool that supports connection to MCP server via stdio can take advantage of accessing eM Client’s data. Settings for this feature can be found in Settings > Artificial Intelligence > MCP.

2 Likes
11

Subject: eM Client 11 beta MCP server — all tool calls fail, plus two issues that make it hard to diagnose

I’ve spent today getting the MCP server in 11.0.0.0 beta working with Claude Desktop on macOS 27 beta. The server itself starts, authenticates and lists all 28 tools correctly — but no tool call succeeds. I hit two further issues along the way that are worth reporting separately, because together they made this take hours instead of minutes.

1. Every tool call returns a generic error

The handshake works:

{"result":{"protocolVersion":"2025-06-18","capabilities":{"logging":{},"tools":{"listChanged":true}},"serverInfo":{"name":"eM Client","version":"11.0.0.0"}},"id":0,"jsonrpc":"2.0"}

Every tools/call then fails:

{"result":{"content":[{"type":"text","text":"An error occurred invoking 'ListEmailAccounts'."}],"isError":true},"id":1,"jsonrpc":"2.0"}

Same for ListEmailFolders. Notably, calling ListEmailFolders with empty arguments — omitting its required parameters — returns that same generic string rather than a validation error, which suggests all exceptions are being caught and replaced with one message, so the real cause never surfaces.

Reproduced directly over stdio with no MCP client involved, so this isn’t Claude-specific. eM Client was running, MCP server enabled, all accounts ticked under Account access, all tools ticked under Tool access.

ListEmailAccounts failing is fatal for the whole integration, since every other tool needs an account id and that’s the only tool that can provide one.

Could the actual exception, or at least an error code, be included in the tool result?

2. The server doesn’t start unless TMPDIR is inherited

On macOS the server locates its transport via TMPDIR. Claude Desktop launches MCP servers with a reduced environment that omits it, so the server starts, accepts the secret, then fails about two seconds after initialize with:

{"jsonrpc":"2.0","id":null,"error":{"code":-32000,"message":"Timed out while connecting to the MailClient MCP transport."}}

Confirmed with env -i: adding HOME alone still fails, adding TMPDIR makes it work.

This means the config that eM Client’s own “Configure this for me” button writes does not work as-is under Claude Desktop. My workaround is to wrap the command:

"command": "/bin/sh", "args": ["-c", "export TMPDIR=$(getconf DARWIN_USER_TEMP_DIR); exec \"/Applications/eM Client.app/Contents/MacOS/eM Client\" --mcp --mcp-secret <SECRET>"]

Better would be for eM Client to resolve the temp directory itself rather than depending on the parent process’s environment.

3. Error responses use id: null instead of echoing the request id

Errors come back like this:

{"jsonrpc":"2.0","id":null,"error":{"code":-32001,"message":"Invalid MCP secret."}}

The MCP client rejects that at the schema level, because id must be a string or a number. The client then discards the message and shows only “Server disconnected” — the actual error text never reaches the user.

This is what made issue 2 so hard to find. eM Client was reporting a clear, correct error the whole time and the client couldn’t display it. Echoing the request’s id on error responses would fix this.

Happy to run further tests if useful.

1 Like
12

This is now fixed in the version 11.0.108

Win
https://licensing.emclient.com/api/update/emclient.appinstaller

Mac
https://www.emclient.com/dist/latest-beta-mac

1 Like
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Thanx, will try it out

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Tried the version 11.0.108 on MacOS, still the same issue that On macOS the server locates its transport via TMPDIR. Claude Desktop launches MCP servers with a reduced environment that omits it, so the server starts, accepts the secret, then fails about two seconds after initialize with:

{"jsonrpc":"2.0","id":null,"error":{"code":-32000,"message":"Timed out while connecting to the MailClient MCP transport."}}

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We’ve fixed the issue with TMPDIR on Mac and it will be included in the next beta release. Thank you for reporting it.

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Thanx look forward to your update, regards Torben