A side-by-side look at the Sendmux Sdk and Voidmail Agent Email MCP servers: transport, auth, tools, quality signals, and the config to install either one in Claude, Cursor, Windsurf or VS Code.
Verdict: choose Sendmux Sdk for communication work as a local process; choose Voidmail Agent Email for communication as a local process. You can also run both side by side in one mcpServers block.
VOIDMAIL_ADDRESS, VOIDMAIL_CREATOR_DID, VOIDMAIL_CREATOR_SIGNING_KEY_FILE.voidmail_create_account, voidmail_account_info, voidmail_list_inbox.Rows where the two servers differ are marked.
| Spec | V Voidmail Agent Email | |
|---|---|---|
| Category | Communication | Communication |
| Quality signal | 47/100 · Fair | 53/100 · Good |
| Install command | Confirmed | Confirmed |
| Transport | Local subprocess (stdio) | Local subprocess (stdio) |
| Auth | OAuth 2.0 | other |
| Pricing | Freemium | Not declared |
| Required env vars | None listed | VOIDMAIL_ADDRESSVOIDMAIL_CREATOR_DIDVOIDMAIL_CREATOR_SIGNING_KEY_FILE |
| Verified owner | Community listing | Community listing |
| GitHub stars | 65 | 0 |
| Directory activity | 2 views 0 installs 0 upvotes | 0 views 0 installs 0 upvotes |
| Tools | Not listed | 19 |
| Full listing | View Sendmux Sdk | View Voidmail Agent Email |
No tool names declared yet. Check the project README from the listing page.
voidmail_create_accountCreate a new @voidmail.ai inbox with an enrolled DID's signed proof; saves both inbox keys to 0600 files and returns only their pathsvoidmail_account_infoGet account detailsvoidmail_list_inboxList emails with pagination and filters; encrypted ones are decrypted herevoidmail_read_emailRead a specific email, decrypting it here if it is encrypted (auto-marks as read)voidmail_search_inboxSearch on this machine across subject, sender, recipients and text; never a server searchvoidmail_sending_limitsRead sending policy without consuming send capacityvoidmail_send_onceSend one authorized message with a saved operation ID and retained statusvoidmail_send_statusRead the same original send without sending againvoidmail_send_emailLegacy send without durable status; prefer `voidmail_send_oncevoidmail_policyRead the recipient and content policy, approved recipients and pending requestsvoidmail_request_recipientAsk the owner to approve a recipient; returns the approval stepvoidmail_revoke_recipientRemove an approved recipient (restricting needs no owner)Paste either block (or both) into your client config, e.g. claude_desktop_config.json or ~/.cursor/mcp.json. We only show a config when the install command is confirmed.
{
"mcpServers": {
"sendmux-sendmux-sdk": {
"command": "uvx",
"args": [
"sendmux-core"
]
}
}
}
{
"mcpServers": {
"voidmail-agent-email": {
"command": "npx",
"args": [
"-y",
"@voidly/mcp-email@2.0.1"
],
"env": {
"VOIDMAIL_ADDRESS": "YOUR_VOIDMAIL_ADDRESS_HERE",
"VOIDMAIL_CREATOR_DID": "YOUR_VOIDMAIL_CREATOR_DID_HERE",
"VOIDMAIL_CREATOR_SIGNING_KEY_FILE": "YOUR_VOIDMAIL_CREATOR_SIGNING_KEY_FILE_HERE"
}
}
}
}