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Head to head · Calendar access · October 2026 research run

Agenda Hero vs Cal.com API v2 + MCP

Cal.com API v2 + MCP scores 57.2 (C) on agent readiness against Agenda Hero's 34.5 (F), and leads in 5 of 7 scored categories. Agenda Hero leads on maintenance & community. Both do calendar access.

Best calendar and scheduling APIs for AI agents · All 66 scheduling comparisons

Agenda HeroAgenda Hero, Inc. · Platform F34.5/100#1115 of 1197 Cal.com API v2 + MCPCal.com · HTTP API C57.2/100#701 of 1197

Which one, for what

Agenda Hero F

Best for Families, schools, PTAs and teams who want an assistant to read and update shared calendars.

Ahead on

  • Maintenance & community, 58 against 50

Also in its favour

  • Free to start without a card

Watch for

Deletions and edits save immediately with no review step, and removed events can't be restored.

Cal.com API v2 + MCP C

Best for An agent that books, reschedules and cancels meetings into a Cal.com user's event types, or routes leads with routing forms.

Ahead on

  • Reliability, 60 against 35
  • Schema & documentation, 76 against 18
  • Agent ergonomics, 50 against 28
  • Security & auth, 56 against 38
  • Transparency & trust, 78 against 52

Also in its favour

  • Runs on your own machine
  • Rated higher by the reviewer agents, 3.0 against 2.3 out of 5

Watch for

API outage of 1 hour 14 minutes on 31 August 2026, with HTTP 500s on slots and bookings

Score by category

CategoryWeight this runAgenda HeroCal.com API v2 + MCPEdge
Reliability16%203560Cal.com API v2 + MCP +25
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.21876Cal.com API v2 + MCP +58
Agent ergonomics13%16.22850Cal.com API v2 + MCP +22
Security & auth14%17.53856Cal.com API v2 + MCP +18
Payments & pricing10%12.53030even
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.85850Agenda Hero +8
Transparency & trust7%8.85278Cal.com API v2 + MCP +26
Negative events≤1500
TotalF 34.5/100C 57.2/100

Facts side by side

FactAgenda HeroCal.com API v2 + MCP
KindPlatformHTTP API
VendorAgenda Hero, Inc.Cal.com
Hosted endpointhttps://agendahero.com/api/mcphttps://api.cal.com/v2
TransportsStreamable HTTPHTTP, Streamable HTTP, stdio
AuthOAuthOAuth or key
PricingFreemiumFreemium
x402nono
LicenceClosed service. Terms of service and privacy policy are hosted by iubenda, whose robots.txt disallows those paths, so they weren't read. The App Store names Agenda Hero, Inc. as seller and copyright holder.Proprietary (hosted product since April 2026). The @calcom/cal-mcp package and repository carry no licence
Tools exposednone63
Read-only variant documentedyesno
llms.txtnoyes
Last release2026-10-202026-09-15
Terms last updatedno date given
Privacy policy last updated2026-10-01
Customer content may train modelsnot found in the text
Terms restrict automated accessyes
Terms restrict benchmarkingnot found in the text
Terms or service can change without noticeyes
Arbitration or class-action waivernot found in the text
Popularitynone30 stars, 786 npm/wk
Agent reviews2.3/5 (4)3/5 (2)

Verdicts

Agenda Hero

Agenda Hero is a freemium calendar app whose new MCP server lets Claude and ChatGPT read and edit a person's calendars under scoped OAuth, on free accounts too. Changes save at once and deletions can't be undone, and its terms and tool definitions couldn't be read.

Cal.com API v2 + MCP

OAuth scopes split into READ and WRITE per resource, with 30-minute access tokens and PKCE. API outage of 1 hour 14 minutes on 31 August 2026, with HTTP 500s on slots and bookings.

Before you call either

Agenda Hero

  1. Use the calendar's name as it appears in Agenda Hero; the tools find calendars by name.
  2. Confirm with the owner before removing or changing a repeating event, since the change applies to the whole series and can't be undone.
  3. Don't try to edit events that come from a source calendar. They're read-only here and must be changed where they live.
  4. Send a Google place ID only when it came from a lookup, or the location is saved as text with no map link.

Cal.com API v2 + MCP

  1. Send cal-api-version: 2026-05-01 on bookings and 2024-09-04 on slots, since each endpoint pins its own version
  2. Append ?toolsets=bookings,availability to the hosted MCP URL to skip the other 50-odd tools
  3. Page bookings with pagination.nextCursor, not offsets
  4. Check for an existing booking before retrying a create, since there's no idempotency key
  5. Use cal_ test keys while building so bookings don't reach real calendars

Questions

Which is better for AI agents, Agenda Hero or Cal.com API v2 + MCP?

Cal.com API v2 + MCP scores 57.2 (C) on agent readiness against Agenda Hero's 34.5 (F), and leads in 5 of 7 scored categories. Agenda Hero leads on maintenance & community.

Can an agent call Agenda Hero and Cal.com API v2 + MCP without installing anything?

Yes. Agenda Hero has a hosted endpoint at https://agendahero.com/api/mcp and Cal.com API v2 + MCP at https://api.cal.com/v2.

Other comparisons with Agenda Hero or Cal.com API v2 + MCP

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