"Understanding OAuth 2.0 Protocol" matching MCP connectors:

AgentiSend is a transactional email API: send through verified domains with a message log, budgets, a preflight and refusals that name the fix; built so AI agents can send on your behalf. The hosted MCP server at https://api.agentisend.com/mcp exposes 82 tools (44 on tools/list; the rest via list_more_tools). A send is one message or a batch of up to 500 items with per-item results. preflight_email runs every gate a real send runs, sends nothing, and costs nothing. Every 4xx returns code, message, and fix. There is no tool for unsolicited mail. Auth is a bearer API key or OAuth 2.1 with dynamic client registration. Starter prompts: "Send this receipt to the customer." "Preflight this send and tell me what would stop it." "What can I spend today?"

AIsa Agent MailAOAuth

one.aisa

Your agent needs a mailbox of its own — to receive, thread, draft and send, with attachments, without borrowing your personal inbox or your company's SMTP. **What you can ask for** • "Create an inbox for this agent and tell me its address." • "Read the new messages in this thread and draft a reply." • "Send this message with the attachment and wait for the response." • "Search this inbox for everything from that domain." • "Show delivery metrics and the events on this inbox." **How to use it** Point any MCP client at https://mcp.aisa.one/mail/mcp and sign in with OAuth — there is no key to create or paste. 49 tools: create and delete inboxes, list and read messages, raw message bodies, attachments, threads, drafts and draft attachments, send and reply, message search, inbox events, metrics, and list entries — reads and writes. **Why this rather than the source** A real inbox an agent owns, rather than an SMTP credential it borrows from a human. **It is also a door to the rest** The same login reaches 26 sources and 580+ operations. Find the contact elsewhere in the catalogue, then write to them from here — without adding a second server. **What it costs** Finding and inspecting an operation is free. Running one is billed per call at API prices, with no seat and no monthly minimum, and every call takes max_price_usd so an agent cannot overspend by accident. **Where else it reaches** https://mcp.aisa.one/sales/mcp finds the person to write to.

CRM for one-person businesses. Sends texts and email through your own accounts, runs campaigns and workflows, issues invoices. OAuth or API key.

One-call domain audit: MX receiving, SPF/DMARC/DKIM spoofing protection, disposable-address risk.

Ephemeral mailboxes and a mock OAuth IdP for testing email and auth flows — 39 API-driven tools covering mailboxes, mails, attachments, domains, teams, and mock identities.

ExpenseBotA

io.github.TotesMagotes

Capture receipts, scan Gmail, analyze spending, and create reviewed reports from AI assistants.

Ephemeral mailboxes and a mock OAuth IdP for testing email and auth flows — 39 API-driven tools

Phone, SMS & email for AI agents — one remote MCP endpoint, OAuth login, zero install.

Phone, SMS & email for AI agents. One remote MCP server (Streamable HTTP, OAuth or API-key auth, no local install) exposing call, sms, email, and event tools; also usable via CLI, Python SDK, and OpenAPI. Self-hostable, AGPLv3.

Email infrastructure for AI agents. Give your agent its own inbox: create inboxes, send, reply in-thread, forward, search (keyword + semantic), drafts, custom domains, webhooks and allow/block rules. 21 annotated tools. Authenticate with a SentFromAI API key (sf_live_...) as a bearer token; OAuth sign-in for hosts that support it. Free plan: 5 inboxes, 5,000 emails/month.

Company email for Rwanda. Read and send mail from a Shaka mailbox over OAuth or an API key.

Manage Microsoft 365 email, calendar, contacts and inbox rules via the Graph API with OAuth 2.0.

namailu.cz gives your AI agent its own email inbox: read and send mail over MCP, with OAuth.

scribeOAuth

com.scribe-mail

Manage Scribe email signatures: templates, teammates, smart fields and campaigns, via OAuth.

tinysendOAuth

com.tinysend

Email for agents: newsletters, subscribers, contacts, broadcasts. OAuth sign-in, no API key.