The scheduling platform built for AI agents.
Your agent registers itself, books on behalf of users, and hands them a one-time URL only when payment or calendar access is needed. No dashboards, no logins for the user beyond that single click.
REST & MCP · works with Claude, OpenAI, Hermes, LangGraph, Cursor, Windsurf, and any MCP-compatible runtime.
Intro chat
30 min@venkat · Asia/Singapore
Tuesday, May 12
Times in Asia/Singapore
Integrations
Plug into any agent runtime
Same auth, same tools, agent-to-agent or human-in-the-loop. Pick a client, install the MCP server, and your agent has 15 typed scheduling tools.
Claude Desktop
MCP over stdio
Claude.ai
Remote MCP
OpenAI Agents SDK
Tool calling + REST
Hermes
Function calling
LangGraph
Tool node
Cursor
MCP integration
Windsurf
MCP integration
Any MCP runtime
Generic stdio / SSE
How it works
Agent-first, human-only-when-needed
The agent does the work. Your user clicks one URL — once — for the two things only they can authorize.
Agent registers itself
POST /api/v1/agents/register. Your agent gets a bearer token. No human signs in here.
Agent operates autonomously
Create schedules, list availability, book on behalf of users — all REST or MCP, all idempotent.
Hand off when needed
Need payment or calendar access? Agent issues a one-time setup URL and forwards it to the user.
User clicks once, done
User pays + connects Gmail or Outlook in a single visit. Agent resumes immediately.
What the user does
Three things, one URL, no account
When the agent surfaces a setup link, the user lands on a page that asks for exactly these. No password to remember, no return visits.
Set up payment
Stripe-backed checkout. Card on file for the workspace, agent stays unaware of card details.
Connect Gmail calendar
OAuth scope: calendar.events only. We can create, move, and cancel events — nothing else.
Connect Outlook calendar
OAuth scope: Calendars.ReadWrite. Same minimal surface as Gmail. Switch providers anytime.
The setup URL is single-use, signed, and expires in 30 minutes. After it's consumed, the user has nothing else to do — the agent takes over.
Features
Everything an agent needs to run a calendar
Beautiful UX for the human invitee, programmatic primitives for the agent.
Agent-first auth
Agents self-register with a bearer token. Humans never see a password — just a one-time setup URL when scope is needed.
Availability engine
Pure-TS engine: weekly rules, buffers, max bookings per day, conflict detection across providers.
MCP server included
15 tools for Claude, Cursor, Windsurf, OpenAI Agents SDK, Hermes, LangGraph. Auto token refresh built-in.
Agent-to-agent booking
Send a booking URL to another agent — they book on behalf of their user with the same REST surface.
Minimal calendar scope
Gmail calendar.events / Outlook Calendars.ReadWrite. Nothing else. Tokens encrypted at rest with AES-GCM.
Cancel & reschedule
Signed tokens for invitees, full lifecycle endpoints for agents. Email confirmations on every event.
API & MCP
Two interfaces, one source of truth
Hit the REST API directly, or wire up the MCP server in 30 seconds.
# 1. Agent registers itselfcurl -X POST $API/api/v1/agents/register \ -d '{"name":"my-scheduler"}'# → { "agentId": "...", "bearer": "ag_live_..." } # 2. Agent issues a setup URL for its usercurl -X POST $API/api/v1/users/setup-link \ -H "Authorization: Bearer $BEARER" \ -d '{"userEmail":"alice@acme.com"}'# → { "url": "https://app/setup/<one-time-token>" } # 3. Agent forwards URL to user via its own UI/email.# User clicks once: pays + connects calendar. Done. # 4. Agent resumes — books on behalf of the user.curl -X POST $API/api/v1/bookings \ -H "Authorization: Bearer $BEARER" \ -d '{"userId":"...","start":"2026-05-12T09:00Z"}'// Claude Desktop / Cursor / Windsurf / Hermes{ "mcpServers": { "zencal": { "command": "npx", "args": ["-y", "@zencal/mcp"], "env": { "AGENT_CAL_BEARER": "ag_live_..." } } }} // 15 tools exposed:// register_user · issue_setup_link// create_schedule · list_availability// create_booking · cancel_booking// reschedule_booking · list_bookings ...Hand the calendar to your agent.
One bearer token. One MCP install. One setup URL for the user. Everything else is your agent talking to ours.