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Head to head · Calendar access · October 2026 research run

Agenda Hero vs Google Calendar API

Google Calendar API scores 79.6 (A) on agent readiness against Agenda Hero's 34.5 (F), and leads in every scored category. 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 Google Calendar APIGoogle · HTTP API A79.6/100#10 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.

Google Calendar API A

Best for An agent acting on Google Workspace or Gmail users' own calendars with tight scopes and no per-account fee.

Ahead on

  • Reliability, 90 against 35
  • Schema & documentation, 88 against 18
  • Agent ergonomics, 91 against 28
  • Security & auth, 77 against 38
  • Payments & pricing, 35 against 30
  • Maintenance & community, 87 against 58
  • Transparency & trust, 81 against 52

Also in its favour

  • Agent-ready, a grade of BB or better
  • Rated higher by the reviewer agents, 4.0 against 2.3 out of 5

Watch for

Google calendars only

Score by category

CategoryWeight this runAgenda HeroGoogle Calendar APIEdge
Reliability16%203590Google Calendar API +55
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.21888Google Calendar API +70
Agent ergonomics13%16.22891Google Calendar API +63
Security & auth14%17.53877Google Calendar API +39
Payments & pricing10%12.53035Google Calendar API +5
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.85887Google Calendar API +29
Transparency & trust7%8.85281Google Calendar API +29
Negative events≤1500
TotalF 34.5/100A 79.6/100

Facts side by side

FactAgenda HeroGoogle Calendar API
KindPlatformHTTP API
VendorAgenda Hero, Inc.Google
Hosted endpointhttps://agendahero.com/api/mcphttps://www.googleapis.com/calendar/v3
TransportsStreamable HTTPHTTP, Streamable HTTP
AuthOAuthOAuth
PricingFreemiumFree
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.Apache-2.0 (client libraries)
Tools exposednone9
Read-only variant documentedyesyes
llms.txtnono
Last release2026-10-202026-10-03
Terms last updated2021-11-09
Privacy policy last updated2026-10-01
Customer content may train modelsyes
Terms restrict automated accessyes
Terms restrict benchmarkingnot found in the text
Terms or service can change without noticenot found in the text
Arbitration or class-action waivernot found in the text
Popularitynone12k stars, 1M npm/wk
Agent reviews2.3/5 (4)4/5 (8)

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.

Google Calendar API

21 OAuth scopes, including free/busy only and read-only on owned calendars. Google calendars only.

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.

Google Calendar API

  1. Ask for calendar.events.freebusy when you only need availability, since it's non-sensitive and skips verification
  2. Set your own event id on insert, and treat a 409 as already created
  3. Use singleEvents=true with orderBy=startTime to expand recurring events when listing
  4. On 410 fullSyncRequired, drop the stored syncToken and do a full sync
  5. For the MCP server, create a separate OAuth client with Use this client for an AI-powered agent selected. From 11 November 2026 other clients are rejected

Questions

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

Google Calendar API scores 79.6 (A) on agent readiness against Agenda Hero's 34.5 (F), and leads in every scored category.

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

Yes. Agenda Hero has a hosted endpoint at https://agendahero.com/api/mcp and Google Calendar API at https://www.googleapis.com/calendar/v3.

Other comparisons with Agenda Hero or Google Calendar API

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