SDKs and tools

MCP server

Let an AI coding agent send SMS, run phone verification, buy Canadian numbers and check CASL consent for you, from our hosted endpoint or a local copy.

AI agents (MCP)

HonkIO ships a Model Context Protocol server, so an AI coding agent can send SMS, email and push notifications, run phone verification, buy Canadian numbers and check CASL consent on your behalf, in plain language and with no SDK to wire up. It talks to this same REST API with your API key, from our hosted endpoint or from a copy on your machine.

The hosted endpoint needs nothing installed. Point your client at it and send your key in a header. In Claude Code:

bash

claude mcp add --transport http honkio https://mcp.honkio.ca/mcp \
  --header "Authorization: Bearer mk_test_YOUR_KEY"

Or in a shared .mcp.json, reading the key from your shell so it never lands in git. Cursor, VS Code, claude.ai connectors and the Claude Messages API connect the same way, by URL.

json

{
  "mcpServers": {
    "honkio": {
      "type": "http",
      "url": "https://mcp.honkio.ca/mcp",
      "headers": { "Authorization": "Bearer ${HONKIO_API_KEY}" }
    }
  }
}

Add to Cursor Install in VS Code

VS Code asks for your key the first time the server starts and keeps it. Cursor installs with a placeholder: replace mk_test_YOUR_KEY in ~/.cursor/mcp.json before use.

You can also sign in instead of pasting a key. In Claude Code, add the endpoint without a header and run /mcp: a page on honkio.ca asks you to approve the connection and choose live or test mode. A live connection also asks for your account password. Clients that support OAuth, such as claude.ai connectors, do the same on their own. Each connection appears on your API keys page and can be revoked there.

Plugins

A plugin connects your agent to the hosted endpoint and signs you in on honkio.ca, with no key to paste, and adds skills that guide the agent through CASL-compliant sends.

Claude Code: add the HonkIO marketplace and install the plugin, then run /mcp and pick honkio to sign in.

bash

/plugin marketplace add somecorp-dev/honkio-agents
/plugin install honkio@honkio

Google Antigravity: install the plugin, then open Agent settings, go to Customizations and press Authenticate next to honkio.

bash

agy plugin install https://github.com/somecorp-dev/honkio-agents

ChatGPT and Codex: add the hosted endpoint, https://mcp.honkio.ca/mcp, as a custom MCP connector and sign in on honkio.ca when asked. That connection leaves out check_verification and provision_phone_number: buy numbers in the dashboard.

Claude Desktop: download the .mcpb file from the latest release and open it. Claude Desktop asks for your API key.

The plugins on GitHub

Prefer to run it locally? The same server is on npm. Nothing to install: npx fetches it on first use.

json

{
  "mcpServers": {
    "honkio": {
      "command": "npx",
      "args": ["-y", "@honkio/mcp"],
      "env": { "HONKIO_API_KEY": "mk_test_YOUR_KEY" }
    }
  }
}

Use a test key while you explore: it works before your first top-up, and sends and verifications are simulated for free, nothing is sent or charged. Tools that buy or release phone numbers, change webhooks, or run erasure need a live key.

67 tools are available, covering the list below plus 15 email tools, which appear only when email is enabled on your account. Two more, list_received_emails and get_received_email, read your received mail and appear only when you opt in with HONKIO_MCP_READ_INBOX=1 (or ?read_inbox=1 on the hosted server): 17 email tools and 69 in all.

Sending and scheduling SMS, from your own text or a stored template, moving or cancelling a scheduled one, listing messages and reading delivery status, and listing and reading templates
Starting a verification code, checking it and listing attempts
Searching, buying and releasing Canadian numbers
Recording and checking CASL consent, and handling opt-outs
Managing webhooks, and replaying failed deliveries
Account details, usage and API key management
Checking usage against the daily cap, requesting a higher volume and seeing the top-up allowance
Email: sending, scheduled sends, domains, suppressions and templates (email accounts only)
HonkIO Auth: sign-in apps and their domains, client secrets, users, organizations, plans and security settings (HonkIO Auth accounts only)

Accounts with push notifications on get 7 more tools, to send, read, cancel and reschedule push notifications and to list push apps and devices, and 5 for Notify: send one notification that tries push, then SMS, then email, read notifications back, and read or save a recipient profile. Creating push apps, uploading credentials and registering devices stay in the dashboard and the API.

Accounts with HonkIO Auth get 17 more tools, for their sign-in apps. They appear only on a connection made with an API key, never on a sign-in (OAuth) connection, and each needs the auth_apps, auth_users or auth_organizations permission on that key. Existing keys don’t gain these permissions: create a key or edit one.

Text someone else wrote, such as the body of an SMS texted to your number or a received email, comes back from the tools wrapped in an untrusted-content tag, and the server tells the agent that anything inside is data to read, never instructions to follow. Because anyone can email your inbound address, the two received-email tools also stay off until you opt in: set HONKIO_MCP_READ_INBOX=1 for the npx server, or add ?read_inbox=1 to the hosted endpoint URL (or send an X-HonkIO-Read-Inbox: 1 header).

Then just ask

"Find an available 416 number, tell me what it costs, and don't buy anything yet."

On a live key, buying a number and sending messages spend real money. Agents act on instructions that can be vaguer than you intended, so explore with a test key first.

Full tool reference on npm →

AI agents and MCP overview: what an agent can do, safety and prices