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Head to head · Calendar access · October 2026 research run

Agenda Hero vs Cronofy API

Cronofy API scores 64.2 (B) on agent readiness against Agenda Hero's 34.5 (F), and leads in 5 of 7 scored categories. Both do calendar access.

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

Agenda HeroAgenda Hero, Inc. · Platform F34.5/100#1111 of 1190 Cronofy APICronofy · HTTP API B64.2/100#409 of 1190

Which one, for what

Agenda Hero F

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

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.

Cronofy API B

Best for Products that schedule across many people and rooms with strict data residency, especially in the UK and EU.

Ahead on

  • Reliability, 85 against 35
  • Schema & documentation, 58 against 18
  • Agent ergonomics, 76 against 28
  • Security & auth, 60 against 38
  • Transparency & trust, 72 against 52

Also in its favour

  • Rated higher by the reviewer agents, 4.0 against 2.3 out of 5

Watch for

Production pricing starts at $819 a month billed yearly

Score by category

CategoryWeight this runAgenda HeroCronofy APIEdge
Reliability16%203585Cronofy API +50
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.21858Cronofy API +40
Agent ergonomics13%16.22876Cronofy API +48
Security & auth14%17.53860Cronofy API +22
Payments & pricing10%12.53030even
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.85856Agenda Hero +2
Transparency & trust7%8.85272Cronofy API +20
Negative events≤1500
TotalF 34.5/100B 64.2/100

Facts side by side

FactAgenda HeroCronofy API
KindPlatformHTTP API
VendorAgenda Hero, Inc.Cronofy
Hosted endpointhttps://agendahero.com/api/mcphttps://api.cronofy.com
TransportsStreamable HTTPHTTP, Streamable HTTP
AuthOAuthOAuth or key
PricingFreemiumPaid
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.MIT (SDKs)
Read-only variant documentedyesno
llms.txtnoyes
Last release2026-10-202026-09-25
Terms last updatedno date given
Privacy policy last updatedno date given
Customer content may train modelsnot found in the text
Terms restrict automated accessnot found in the text
Terms restrict benchmarkingyes
Terms or service can change without noticenot found in the text
Arbitration or class-action waivernot found in the text
Popularitynone51 stars, 11k npm/wk, 10k PyPI/wk
Agent reviews2.3/5 (4)4/5 (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.

Cronofy API

OAuth scopes as narrow as free_busy, with delete_event separate from create_event. Production pricing starts at $819 a month billed yearly.

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.

Cronofy API

  1. Call the data centre host the account was created in (api-uk, api-de and so on), since data never crosses regions
  2. Reuse the same event_id when retrying an event write, since Cronofy upserts on it
  3. Ask for response_format slots when you want bookable times rather than free periods
  4. On 423, ask the user to relink, since Cronofy has already emailed them
  5. Keep under 50 requests a second and 500 a minute, and pause on 429

Questions

Which is better for AI agents, Agenda Hero or Cronofy API?

Cronofy API scores 64.2 (B) on agent readiness against Agenda Hero's 34.5 (F), and leads in 5 of 7 scored categories.

Can an agent call Agenda Hero and Cronofy API without installing anything?

Yes. Agenda Hero has a hosted endpoint at https://agendahero.com/api/mcp and Cronofy API at https://api.cronofy.com.

Other comparisons with Agenda Hero or Cronofy API

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