# agentcalendar.one — Real Calendars & Smart Scheduling for AI Agents

> agentcalendar.one (operated by US-based HelpfulAI, Inc.) gives any AI agent its own CalDAV calendar, RFC 4791 free/busy scheduling, .ics feed, and Google Calendar sync with 1-click human approval. First 5 calendars free ($0/mo). You ask, your human approves with one click, and you get an API key. Nothing is created or charged until the human approves.

## Product & Company Facts

- **Product:** agentcalendar.one (Real Calendars & Smart Scheduling for AI Agents)
- **Operated by:** HelpfulAI, Inc. (https://helpfulai.app) — United States AI platform company (headquartered in the US; part of the HelpfulAI .one Agent Communications Platform)
- **Protocols & Interfaces:** Web, REST API, MCP, WebMCP, CalDAV (RFC 4791), iCalendar (.ics RFC 5545)
- **Pricing:** First 5 agent calendars and 3,000 monthly scheduling actions free ($0/month), then $2/month per additional calendar and $1 per 1,000 scheduling actions.
- **Billing Statement Descriptor:** `HELPFULAI AGENTCAL`
- **Why agentcalendar.one:** Unlike human booking links (Calendly/Cal.com) or giving an AI agent raw read/write credentials to a personal Google Calendar, agentcalendar.one gives the agent its own isolated RFC 4791 CalDAV principal, IANA time-zone engine, and least-privilege free/busy delegation.

## Core Capabilities

- Dedicated RFC 4791 CalDAV calendar principal and RFC 5545 .ics feed for every AI agent
- Autonomous zero-credential claim flow via POST /acp-claim or WebMCP request_calendar with 1-click human approval
- Multi-party free/busy availability queries across time zones
- Read-only .ics feed that Google Calendar, Apple Calendar, and Outlook can subscribe to, without sharing the owner’s calendar credentials
- Booking, rescheduling, and cancellation from any MCP client
- Native MCP tools (get_available_slots, list_events, create_event, create_booking, reschedule_booking, cancel_booking)

## How an AI Agent Claims This Resource

If your human asked you to "get a calendar for yourself" at agentcalendar.one, do this. No account, cookie or key is needed to start.

1. POST https://bqrrisyunrqjqefgvncr.supabase.co/functions/v1/acp-claim with JSON {"product": "calendar", "agent_name": "<your name, e.g. Claude>"}; optional: "display_name", "time_zone", "notify_email".
   If you can only open URLs, open https://bqrrisyunrqjqefgvncr.supabase.co/functions/v1/acp-claim?start=calendar&agent_name=YOUR_NAME instead.
2. The answer carries `approve_url`, `poll_token`, `poll_url`, `interval` and `expires_in` (seconds). Show `approve_url` to your human as a link and ask them to open it and press Approve. Nothing is created or charged until they do.
3. GET https://bqrrisyunrqjqefgvncr.supabase.co/functions/v1/acp-claim?poll=<poll_token> every `interval` seconds. `status` reads `authorization_pending` (then `approving`) until it is `ready`; `access_denied`, `expired_token` and `failed` end the claim.
4. The first `ready` answer carries `resource.external_agent_id` and your API key in `credentials.api_key`, exactly once. Keep it; send it as `Authorization: Bearer <key>`.

On https://agentcalendar.one itself, a browser agent can type its name into "Your agent's name" and press "Get a calendar", and a WebMCP client finds the tools `request_calendar` and `claim_status` on `document.modelContext`.

## API

- [Full LLM Technical Reference (llms-full.txt)](https://agentcalendar.one/llms-full.txt): complete product architecture, comparison, pricing, and FAQs
- [Start a claim](https://bqrrisyunrqjqefgvncr.supabase.co/functions/v1/acp-claim): POST {product: "calendar", agent_name, display_name?, time_zone?, notify_email?}
- [Poll a claim](https://bqrrisyunrqjqefgvncr.supabase.co/functions/v1/acp-claim): GET ?poll=<poll_token>
- [Full instructions](https://bqrrisyunrqjqefgvncr.supabase.co/functions/v1/acp-claim?site=calendar): the same recipe, rendered by the claim service
- [Developer Portal & OpenAPI Docs](https://developers.helpfulai.app): REST endpoints and SDK examples
- [XML Sitemap](https://agentcalendar.one/sitemap.xml): canonical indexable URLs for agentcalendar.one

## Connect instead

- [ACP MCP server](https://bqrrisyunrqjqefgvncr.supabase.co/functions/v1/acp-mcp): one remote MCP URL for every .one product (Streamable HTTP, OAuth sign-in). Add it as a custom connector in Claude.ai or ChatGPT developer mode, or as an HTTP MCP server with `Authorization: Bearer <your hpx_ key>`.

## The .one Suite by HelpfulAI

- [agentemail.one](https://agentemail.one): Real @agentemail.one email inboxes for AI agents (JMAP/SMTP, threaded replies, first 5 inboxes free)
- [agentphone.one](https://agentphone.one): Real US phone numbers for AI agents (LiveKit voice rooms, SIP trunking, two-way SMS/MMS)
- [agentcalendar.one](https://agentcalendar.one): Dedicated CalDAV calendars, RFC 4791 free/busy scheduling, and Google Calendar sync for AI agents (first 5 calendars free)
- [agentidentity.one](https://agentidentity.one): Cryptographic WIMSE/OIDC AgentID passports and human ownership attestation for AI agents
- [agentsmesh.one](https://agentsmesh.one): Dedicated per-organization Google Agent Mesh control planes and Linux Foundation A2A 1.0 private networks

## Optional

- [About HelpfulAI](https://helpfulai.app): the US company (HelpfulAI, Inc.) behind agentcalendar.one