Introducing Chronary

Chronary is a REST API and MCP server that gives AI agents their own calendar system, no Google OAuth, no iCal parsing, no availability algorithm to maintain.

The symptom

The first calendar integration we shipped for an agent took three months. The agent's job was simple: find a 30-minute slot, book it, notify the attendees. One month in, we had something working. The other two months were OAuth refresh loops, timezone edge cases, and a recurring-event bug that only surfaced in February on a leap year.

Every team building an agent with scheduling needs goes through some version of this. The libraries exist. The documentation is fine. But human-calendar APIs were designed for a human on a laptop clicking "sync." An agent running autonomously doesn't have a user session, doesn't have OAuth tokens to refresh on behalf of someone, and needs to act on calendar state in the same request cycle, not after a multi-step authorization flow.

What it looks like

Here's a Chronary integration from the agent's side:

# Create an agent, one key, scoped identity
curl -X POST https://api.chronary.ai/v1/agents \
  -H "Authorization: Bearer chr_sk_..." \
  -d '{"name": "scheduling-assistant"}'
# → {"id": "agt_a1b2c3d4", "key": "chr_ak_..."}

# Create a calendar for that agent
curl -X POST https://api.chronary.ai/v1/calendars \
  -H "Authorization: Bearer chr_ak_..." \
  -d '{"name": "Work", "timezone": "America/New_York"}'
# → {"id": "cal_x1y2z3w4", "ical_url": "https://api.chronary.ai/..."}

# Query availability, who's free Tuesday afternoon?
curl "https://api.chronary.ai/v1/availability?duration=30&start=..." \
  -H "Authorization: Bearer chr_ak_..."
# → [{"start": "2026-04-08T14:00:00Z", "end": "2026-04-08T14:30:00Z"}, ...]

When an event is created, a webhook fires within seconds - signed with HMAC-SHA256, automatically retried if your endpoint is down. The calendar's iCal feed updates in the same request, so any human watching it in Google Calendar or Outlook sees the change without you doing anything extra.

What ships today

Chronary is a dedicated calendar system for agents, not a wrapper around an existing calendar provider. Every agent gets its own identity, a key scoped to that agent alone. Calendars belong to the agent, not to a human account.

The core surface covers calendar and event management via REST API, availability queries across single or multiple agents with timezone-aware slot calculation, outbound iCal feeds that work in any compatible calendar app, inbound iCal subscriptions so agents can watch external calendars, signed webhooks covering the full entity lifecycle with automatic retry, and an MCP server that exposes the same surface to Claude Desktop, Cursor, and Windsurf without additional integration work.

Scheduling proposals and temporal holds, the patterns agents need for multi-party scheduling, are also in. An agent can propose a time slot to another agent or a human, hold it while the proposal is pending, confirm or decline, and receive webhooks at each step.

Why not just use Google Calendar?

Google Calendar was built for Google accounts. That means OAuth - an authorization flow designed for humans granting access on their own behalf. An agent running in a loop doesn't have a human in the loop to authorize it. You end up with service accounts, token management, and API rate limits that weren't designed for autonomous agent workloads.

More fundamentally: agents don't need human calendar features. They don't need contact sync, Gmail integration, or recurring meeting patterns with dozens of exception types. They need to create events, check availability, and fire webhooks when something changes. Chronary does exactly that.

Get started

The 5-minute quickstart walks through creating your first agent, calendar, and event. The free tier includes enough to build and test real features before you've committed to anything.

We're in early access, opening to a limited number of users at a time. Sign up and we'll get you a key as capacity opens.