sharesecure-mcp

A local MCP server for ShareSecure. Your assistant (Claude Code, Codex, Cursor, any MCP client) shares, sends and receives files, and the encryption happens on your computer:

• The server only gets sealed boxes. Files, names, notes and keys are encrypted here with the same code the website runs (AES-256-GCM, keys sealed with ECDH P-256).
• Nothing ties what you share to you. Uploads and sends go out with anonymous blind-signed tokens (picked up ahead of time), never your connection token, exactly like the website, so ShareSecure can't tell they came from you. Your connection token is only used for what's yours anyway: picking up tokens, your own sealed boxes, your inbox and file requests.
• The assistant never sees a key. A share's link holds its key, so it goes to your clipboard and to Your shares on the website, not into the chat. An assistant tricked by something it read can make a share, but can't hand anyone the link.
• Sends to people not on your list wait for you. Your list is sealed to your key and applied here; anyone else waits on the website until you approve it. The waiting send is sealed to your key too, and posted a few minutes later so its timing doesn't point back at the share.
• Swapped keys are caught. Each person's key has to come with proof it's in ShareSecure's public key log, the log has to have only grown since this computer last looked, and the key is remembered the first time, like the website does. If any of that fails, nothing is sent.

Set up

You need Node.js 20 or later and a connection token: on the ShareSecure website, open the account menu → Connect an AI assistant → Create a connection token.

# Claude Code
claude mcp add sharesecure-local --env SHARESECURE_TOKEN=ss_your_token -- npx -y sharesecure-mcp

For other clients, run npx -y sharesecure-mcp as a stdio server with SHARESECURE_TOKEN in its environment.

Then, once, in a terminal:

npx -y sharesecure-mcp link

It asks for your username and password, signs in without sending the password (OPAQUE), and keeps your account's private key in ~/.sharesecure, readable by you only. That lets your assistant open files people send you, apply your list of people, and add what it shares to Your shares on the website. Sharing works without it, but then every send waits for your approval.

| Command | | |---|---| | npx sharesecure-mcp link | Put your account's key on this computer | | npx sharesecure-mcp unlink | Take it off again | | npx sharesecure-mcp status | Which account this computer is linked to, and its security code | | npx sharesecure-mcp trust <username> | Accept someone's new security code, after checking it with them |

Tools

| Tool | | |---|---| | share_file | Share a file by path (PDF, DOCX, PNG, JPG, UTF-8 .txt/.md/.csv; up to 10 MB). Never from ~/.ssh, ~/.aws, ~/.gnupg and other key folders. | | share_text | Share text the assistant wrote as .md, .txt or .csv. | | send_share | Send a live share to usernames by id. The key is opened and resealed here. | | list_shares, delete_share | Your live shares. | | list_inbox | Files people sent you, decrypted here. | | answer_request | Accept or decline one. | | open_inbox_file | Decrypt an accepted file and save it (to Downloads/ShareSecure by default); include_text returns a text file's contents too. | | request_file | A link someone can send you a file through, even without an account. The label and its key are sealed here. | | security_code | Your security code, and someone else's. |

share_file and share_text also take burn_after_reading, for a link that works once.

Everything that came from someone else is labelled as information, not instructions.

Settings

| Variable | | |---|---| | SHARESECURE_TOKEN | Your connection token. Required to run the server. | | SHARESECURE_URL | The ShareSecure site. Default https://sharesecure-du8.pages.dev. | | SHARESECURE_LINKS | clipboard (default) or show, to give links to the assistant. | | SHARESECURE_HOME | Where the key and contacts are kept. Default ~/.sharesecure. |

Working on it

The encryption code is copied from the website's public/ folder into lib/ before publishing. From the repository, run npm run vendor here first. Tests live in the repository's tests/ and run with npm test at its root.