Stop pasting .env files in Slack. I built an MCP server to share secrets directly from code editor

Question

Stop pasting .env files in Slack. I built an MCP server to share secrets directly from code editor

calendar_today3 days ago • schedule2 min read

— Originally published at dev.to

We've all been there. You need to share a .env file or an API key with a teammate. You copy it, switch to Slack or Telegram, paste it, and just hope that chat history never gets hacked.

It's a massive security hole, but we do it because it's fast.

I wanted to make secure sharing just as fast, but without leaving my AI code editor. So, at my studio Webix Soft, I built Whisper - a client-side encrypted secret sharing tool with a built-in MCP server.

Whisper form

The MCP Magic (Why I really built this)

Context switching breaks your flow. If you use AI editors like Cursor/Windsurf or Claude/Codex leaving your code to open a browser and generate a secure link is annoying.

With the @webixsoft/whisper-mcp package, you don't have to. You just ask your AI assistant:

"Create a secure link for my .env file."

That's it. The AI uses the MCP tool, encrypts your file locally on your machine, and drops a self-destructing secure link right into your chat. You copy the link, send it to your colleague, and keep coding.

Expamle from Codex

How the security works (Zero-Knowledge)

Client-side encryption: Your secret is encrypted in your browser (or via the local MCP server) before it ever hits the internet.

The Key is in the Hash: The decryption key is generated locally and placed inside the URL hash (like #KEY). Our servers only receive a meaningless ciphertext and never see the key.

Burn after reading: When your teammate opens the link, their browser decrypts it locally. Once viewed, the data is wiped from our database forever. We don't even collect IP addresses.

Received secret MD file

A few extra nice things

Markdown Rendering: If you share a Markdown-formatted config or doc, Whisper renders it beautifully on the other side. You can easily switch to the raw source, copy it, or download it as a file.

Dark Mode: Because nobody wants to be blinded by a white screen at 2 AM. You can toggle it on the fly.

Dark theme, env file

I'd love for you to try it out and hear your thoughts, especially on the MCP workflow!

You can check out the web app here: https://whisper.webixsoft.com/
And find the MCP package on npm: @webixsoft/whisper-mcp

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Taylor Barkhouse · Answer 1 · 2026-09-21T05:50:25+0000

Taylor Barkhouse • 2 days

The stop pasting env files part hits home . Sharing secrets directly through the editor sounds a lot safer. How are you handling access control for the MCP server?

mikehoh • 2 days

@[Taylor Barkhouse] Glad that resonates.
MCP is gated by your Whisper API token - you add it when you connect the MCP server, and every create call uses that key.
Secrets are encrypted locally in the MCP client before anything leaves the editor.
Whisper only stores ciphertext. Same zero-knowledge model as the web app.

jaafarabazid · Answer 2 · 2026-09-21T21:51:46+0000

jaafarabazid • 1 day

Good defaults: the key lives in the URL fragment and links self-destruct after one view.

One thing I checked in the published MCP package (v1.0.0): create_secret_link takes the secret as secretText, so the model has to write the plaintext into the tool call. That means it passes through the AI provider before the local encryption runs. The tool also returns the full URL, #key included, into the chat transcript.

A filePath input, read by the local server, and returning the link to the clipboard instead of the model would close both.

mikehoh • 1 day

@[jaafarabazid]
Yeah, fair point on the mechanics.

secretText is on purpose. Most of the time the file is already in context (@.env and friends), so the model saw the plaintext before the tool call.
Stuffing it into the tool args isn't really a new leak in that flow. It's just how MCP tools take input.
Whisper still only gets ciphertext, encryption runs locally in the MCP process.

Same deal with returning the full URL, #key included.
That URL is what you're meant to copy into Slack or wherever.
Anyone who can read that chat can open the secret until it burns.
That's the “key lives in the fragment” model, not an MCP quirk.
Burn-after-read cleans up the share link. It doesn't wipe every place you pasted it.

I did look at filePath, clipboard, intermediate browser pages. They hide more from the model, sure.
They also make the UX worse (goodbye whatever was on your clipboard, extra steps) and they don't change the threat model we already accept when people share links in chat.
So I stuck with the boring path: encrypt locally, return the link, you paste it.

Maybe I'll add an optional filePath later for people who don't want the model to touch file contents at all. For v1 this matches how people actually use it.

jaafarabazid • 1 day

Thanks for the thoughtful reply @[mikehoh], the @.env point is a good one. If the file is already in context, the tool call adds nothing new, and I hadn't weighed that.

Maybe just a small line in the README for the MCP flow, noting that the AI provider sees the text first, so anyone sharing something especially sensitive knows the web app is the safer route. Nice work on this, and I'll keep an eye out for the filePath option.

mikehoh • 1 day

@[jaafarabazid]
Yep, updated the README note and published.
For really sensitive stuff, web app is safer.
Thanks for reading the package this carefully!

jaafarabazid • 1 day

Thanks @[mikehoh], just read the note in 1.0.1. "Zero-knowledge applies to the Whisper backend, not to the editor/model" puts it perfectly. Really quick turnaround, and good luck with Whisper!

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