HAIL.SO
CALL.
TEXT.
EMAIL.
The communication MCP server for AI agents

One endpoint gives any agent its own phone number, SMS line, and email inbox — inbound and outbound. Real-world communication, as standard tool calls.

Get Access →Read the MCP docs →
★ A universal comms layer for AI agentsEst. 2026Open source · Managed cloud
■ One-click connect

Already in your stack. One click away.

Pick your client. Approve the consent screen. Your agent gets call / sms / mail tools. No API keys, no install.

ClaudeConnect ↗ChatGPTConnect ↗GeminiConnect ↗CursorConnect ↗WindsurfConnect ↗GitHub CopilotConnect ↗ZedConnect ↗RaycastConnect ↗+See all clients/mcp ↗
■ The problem / today

Your agent can think. It can't call, text, or email.

LLMs are trapped in chat. The moment your agent needs to reach a real person, the work stops — or you spend six weeks wiring carriers, then six more keeping it alive.

Agent · chat-onlyno channels
Call the vendor and confirm our Q3 terms?
On it — drafting the message…
…but I can't actually reach anyone from here.
⊘CALL
⊘SMS
⊘EMAIL
▌ work stops here →

Without Hail. With Hail.

■ 01 / Build vs. plug-in
Without Hail
✕Managing Twilio SIP trunks, WebRTC, and webhooks just to get one agent on a call.
✕Fighting 900ms latency and writing state logic to handle human interruptions mid-call.
✕Parsing messy multipart HTML email into something an LLM can actually read.
✕Three vendor accounts, three billing cycles, three sets of API keys.
With Hail
→One MCP endpoint. Plug into your existing agent stack.
→Built-in low latency, with native interruption handling.
→Clean, token-optimized JSON — pre-parsed for context windows.
→One platform. One key. One bill.

Three channels. One API.

■ 01 / Communication as tool calls
VOICE

Call.

Place and receive real calls on a real number. Streaming transcripts, turn detection, voicemail — as structured events.

Call the dentist and confirm my 3 PM Thursday.
Calling now.
MCPtool call✓ connected
ƒplace_call
{
to: "+14155552240",
system_prompt: "Confirm the 3 PM Thursday appointment."
}
00:00 / 00:08
AGENT
Hi, this is Hail calling to confirm your three o'clock meeting on Thursday — does that still work?
CALLEE
Yes, Thursday at three works for me. See you then.
✓Confirmed — Thursday at 3:00 PM.
LOCAL · TOLL-FREEUS · CA
TRANSCRIPTSREAL-TIME
SIP TRUNKINCLUDED
STIR/SHAKENA-ATTESTED
SMS

Text.

Send and receive SMS / MMS on the same number. 10DLC, opt-outs, carrier filtering — all handled for you.

Text Sam that order #2231 ships today — and let him opt out.
On it.
MCPtool call✓ delivered
ƒsend_sms
{
to: "+14155550148",
body: "Hi Sam — order #2231 ships today. Reply STOP to opt out."
}
✓Sam replied STOP, so I opted him out automatically.
SMS · MMS2-WAY
10DLCHANDLED
STOP · HELPAUTOMATIC
SHORTCODESAVAILABLE
MAIL

Email.

Two-way email on you.hail.so, or your own domain. Threaded, searchable, attachments parsed into clean content.

Email finance@vendor.io that invoice #4471 is paid.
Sending now.
MCPtool call✓ sent
ƒsend_email
{
to: ["finance@vendor.io"],
subject: "Invoice #4471 — paid",
body_text: "Invoice #4471 cleared this morning — thanks!"
}
✓Sent and DKIM-signed — their reply landed in the same thread.
SEND · RECEIVESMTP · IMAP
SPF·DKIM·DMARCAUTO
THREADINGMSG-ID
ATTACHMENTSPARSED

Watch the wire.

■ hail tail --follow · all channels
~ / agent · hail tail --followLIVE
● STREAMINGCH · —EVENTS 59UPTIME 01:14
★ Every channel · one stream

Calls, SMS, and email land in the same feed — your terminal, the console, or the SDK's event stream. Same data, same shape.

CALLStreaming transcripts, turn detection
SMSInbound & outbound, threaded by contact
MAILFull body, attachments, headers parsed
TOOLEvery agent tool call, with arguments
Read the docs→

Built for agents that do things.

■ 03 / Use cases
01 / SUPPORT

Support lines

Answer 24/7, resolve L1 end-to-end, escalate to a human with full context.

VOICE · SMS · MAIL
02 / SCHEDULING

Book & rebook

Call offices and vendors, confirm by text, drop the result into the calendar.

VOICE · SMS
03 / OUTBOUND

Outreach

Dial warm leads, text follow-ups, hand hot prospects to a human. Logged to CRM.

VOICE · SMS · MAIL
04 / CONCIERGE

Concierge

A number users text "book a table for two at 8" — the agent calls and confirms.

SMS · VOICE

Self-host it. Or let us run it.

■ 04 / How to get it
● AVAILABLE NOW

Self-host.

Open source, AGPL. Runs anywhere Docker runs. Bring your own carrier and domain.

◆ Full source on GitHub — fork & extend◆ Deploy on Fly, Railway, Render, or your infra◆ MCP server, CLI, and Python SDK included
Self-host on GitHub→
● AVAILABLE NOW

Managed.

Every channel on one platform, one key, and one invoice — instead of Twilio, a mail vendor, and carrier accounts. Pay-as-you-go, so there's practically zero risk to start.

◆ One invoice for voice, SMS & email◆ Pay-as-you-go — no contract, no minimums◆ Replaces Twilio + a mail vendor + carrier accounts
Get Access →
See full pricing — free credit, then pay per use→AI Model Pricing Database — compare every provider's rates→
■ 05 / Trust

Boring about compliance.

OPEN SOURCE
Audit the code
Fork it. Run it on your infra.
SHIPPED
TCPA-aware
Quiet hours, opt-outs, consent.
ROADMAP
EU region
Data residency, GDPR-native.
■ 06 / Get access

Your agents, on every channel.

Hosted phone numbers, two-way SMS and email, compliance, dashboard. Sign up in 30 seconds — $5 free credit, no card.

★ New workspace — 30s
→ $5 free credit on signup
→ One phone number, SMS line & email address
→ CLI, MCP, REST — same key
Get Access →
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