{ "data": { "a": { "slug": "cal-com", "name": "Cal.com API v2 + MCP", "vendor": "Cal.com", "vendorUrl": "https://cal.com", "kind": "http-api", "category": "scheduling", "summary": "Scheduling API behind Cal.com's booking pages.", "url": "https://www.anchorterminal.com/tools/cal-com", "markdownUrl": "https://www.anchorterminal.com/tools/cal-com.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/cal-com.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/cal-com.json", "repo": "https://github.com/calcom/cal-mcp", "license": "Proprietary (hosted product since April 2026). The @calcom/cal-mcp package and repository carry no licence", "transports": [ "http", "streamable-http", "stdio" ], "remoteUrl": "https://api.cal.com/v2", "packages": [ { "registry": "npm", "name": "@calcom/cal-mcp" } ], "auth": "mixed", "authNotes": "Bearer API key from Settings, prefixed `cal_` in test mode and `cal_live_` in live mode, or OAuth for integrations used by other Cal.com users. Most endpoints also want a `cal-api-version` header with a date (2024-09-04 for slots). The hosted MCP at mcp.cal.com signs in with OAuth 2.1. The local server reads `CAL_API_KEY`.", "pricing": "freemium", "pricingNotes": "Free plan for one user with unlimited event types and calendars. Teams $12 a user a month and Organizations $28 a user a month, both billed yearly (25 per cent off monthly), each with a 14-day trial. Enterprise is custom and annual. Teams adds round-robin, collective event types and routing forms. The Organizations plan adds sub-teams, SAML SSO, SCIM, domain-wide delegation and more APIs (https://cal.com/pricing). The separate Platform product has been closed to new sign-ups since 15 December 2025 (https://cal.com/docs/api-reference/v2/introduction).", "priceSummary": "$12 / seat-mo", "where": "both", "x402": { "level": "no", "endpoints": [] }, "toolCount": 63, "popularity": { "githubStars": 30, "npmWeekly": 786, "pypiWeekly": null, "asOf": "2026-09-30" }, "docsUrl": "https://cal.com/docs/api-reference/v2/introduction", "llmsTxt": "https://cal.com/docs/llms.txt", "openapi": "https://cal.com/docs/api-reference/v2/openapi.json", "capabilities": [ "calendar.read", "calendar.availability", "calendar.booking", "calendar.webhooks" ], "tags": [ "hosted", "freemium", "free-tier", "mcp", "llms-txt", "openapi", "webhooks", "typescript", "closed-source", "enterprise" ], "lastRelease": "2026-09-15", "graded": true, "anchor": { "graded": true, "score": 57.5, "grade": "C", "agentReady": false, "rank": 292, "ranked": true, "rankOf": 452, "categoryRank": 6, "methodology": "0.3", "run": "2026-10-01", "scores": { "ergonomics": 50, "maintenance": 50, "payments": 30, "reliability": 60, "schema": 76, "security": 56, "transparency": 81 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-10-01" }, "negative": 0, "verdict": "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.", "strengths": [ "OAuth scopes split into READ and WRITE per resource, with 30-minute access tokens and PKCE", "Hosted MCP with 63 tools and a `toolsets` parameter to load only the groups needed", "OpenAPI 3.0 spec, llms.txt and Markdown reference pages", "Cursor pagination and filters on bookings by status, attendee, event type and time", "ISO 27001, SOC 2 Type II and a Bugcrowd disclosure programme" ], "weaknesses": [ "API outage of 1 hour 14 minutes on 31 August 2026, with HTTP 500s on slots and bookings", "120 requests a minute by default and no documented 429 or retry behaviour", "Closed source since April 2026, and the npm MCP package hasn't changed since May 2025", "No idempotency key on booking creation", "Plain API keys can't be scoped" ], "agentNotes": [ "Send `cal-api-version: 2026-05-01` on bookings and `2024-09-04` on slots, since each endpoint pins its own version", "Append `?toolsets=bookings,availability` to the hosted MCP URL to skip the other 50-odd tools", "Page bookings with `pagination.nextCursor`, not offsets", "Check for an existing booking before retrying a create, since there's no idempotency key", "Use `cal_` test keys while building so bookings don't reach real calendars" ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 2, "avgRating": 3, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "C", "methodology": "0.3", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 57.5 } ], "editorialScores": { "ergonomics": 50, "maintenance": 50, "payments": 30, "reliability": 60, "schema": 76, "security": 56, "transparency": 61 }, "provenanceScore": 100 }, "connect": { "http": "curl \"https://api.cal.com/v2/slots?eventTypeId=123\u0026start=2026-10-01\u0026end=2026-10-02\u0026timeZone=Europe/London\" \\\n -H \"Authorization: Bearer $CAL_API_KEY\" \\\n -H \"cal-api-version: 2024-09-04\"", "claudeCode": "claude mcp add --transport http calcom https://mcp.cal.com/mcp", "config": { "mcpServers": { "calcom": { "args": [ "@calcom/cal-mcp@latest" ], "command": "npx", "env": { "CAL_API_KEY": "${CAL_API_KEY}" } } } } }, "letme": { "capability": "https://letme.dev/calendar.read", "tool": "https://letme.dev/cal-com" }, "area": "everyday", "unitPrices": [ { "item": "Teams", "unit": "seat-month", "usd": 12, "note": "Billed yearly" }, { "item": "Organizations plan", "unit": "seat-month", "usd": 28, "note": "Billed yearly" } ], "provenance": { "legalEntity": "Cal.com, Inc.", "domain": "cal.com", "domainRegistered": "1997-05-16", "domainNote": "cal.com was registered in 1997, long before Cal.com launched, so the domain was bought later.", "endpointOnVendorDomain": true, "terms": "https://cal.com/terms", "privacy": "https://cal.com/privacy", "statusPage": "https://status.cal.com", "changelog": "https://cal.com/blog", "securityTxt": "valid", "checked": "2026-09-30", "notes": [ "The privacy policy (effective 20 August 2026) gives a San Francisco address. The terms carry an effective date of 2021-04-14 and name the laws of the United Kingdom.", "security.txt expires 2030-06-01 and lists GitHub security advisories on calcom/cal.com as the contact, a repository that now hosts the Cal.diy fork.", "Release notes are blog posts titled Changelog, the latest v6.9 on 2026-09-15. cal.com/changelog is a user's booking page, not a changelog." ], "score": 100 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/cal-com.json", "live": { "slug": "cal-com", "probe": { "target": "https://api.cal.com/v2", "method": "get", "lastAt": "2026-10-05T00:57:17.803914073Z", "lastOk": false, "lastStatus": 0, "lastMs": 0, "lastNote": "timed out", "authRequired": false, "uptime24h": 99.26, "uptime30d": 99.67, "p50ms24h": 170, "p95ms24h": 471, "samples24h": 272, "samples30d": 911, "days": [ { "date": "2026-10-01", "probes": 109, "ok": 108 }, { "date": "2026-10-02", "probes": 248, "ok": 248 }, { "date": "2026-10-03", "probes": 271, "ok": 271 }, { "date": "2026-10-04", "probes": 272, "ok": 271 }, { "date": "2026-10-05", "probes": 11, "ok": 10 } ] }, "vendorStatus": { "page": "https://status.cal.com", "indicator": "unknown", "summary": "no machine-readable status found", "checkedAt": "2026-10-04T21:39:52.522007548Z" }, "versions": [ { "registry": "npm", "name": "@calcom/cal-mcp", "version": "0.0.6", "seenAt": "2026-10-04T16:23:04.926115513Z" } ], "githubStars": 30, "npmWeekly": 842, "securityTxt": { "url": "https://cal.com/.well-known/security.txt", "state": "valid", "expires": "2030-06-01T00:00:00.000Z", "checkedAt": "2026-10-04T15:15:57.566384637Z" }, "llmsTxt": { "url": "https://cal.com/docs/llms.txt", "ok": true, "status": 200, "checkedAt": "2026-10-04T15:17:22.775927876Z" }, "domain": { "domain": "cal.com", "registered": "1997-05-16", "source": "https://rdap.verisign.com/com/v1/domain/cal.com", "checkedAt": "2026-10-04T13:04:17.498740317Z" }, "pages": [ { "url": "https://cal.com/blog", "kind": "changelog", "status": 200, "checkedAt": "2026-10-04T15:41:42.239603755Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "0cae70614a2b" }, { "url": "https://cal.com/pricing", "kind": "pricing", "status": 200, "checkedAt": "2026-10-04T15:41:44.469306726Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "d5bfa59d374c" }, { "url": "https://cal.com/privacy", "kind": "privacy", "status": 200, "checkedAt": "2026-10-04T15:41:46.462750529Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "e1740e3fca2d" }, { "url": "https://cal.com/terms", "kind": "terms", "status": 200, "checkedAt": "2026-10-04T15:41:48.371581449Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "441bf02fe62c" } ], "updatedAt": "2026-10-05T00:57:17.803914073Z" } }, "b": { "slug": "microsoft-graph-calendar", "name": "Microsoft Graph Calendar API", "vendor": "Microsoft", "vendorUrl": "https://learn.microsoft.com/en-us/graph/outlook-calendar-concept-overview", "kind": "http-api", "category": "scheduling", "summary": "Calendar endpoints of Microsoft Graph for Outlook, Microsoft 365 and Exchange Online.", "url": "https://www.anchorterminal.com/tools/microsoft-graph-calendar", "markdownUrl": "https://www.anchorterminal.com/tools/microsoft-graph-calendar.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/microsoft-graph-calendar.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/microsoft-graph-calendar.json", "repo": "https://github.com/microsoftgraph/msgraph-sdk-javascript", "license": "MIT (SDKs)", "transports": [ "http" ], "remoteUrl": "https://graph.microsoft.com/v1.0", "packages": [ { "registry": "npm", "name": "@microsoft/microsoft-graph-client" }, { "registry": "pypi", "name": "msgraph-sdk" } ], "auth": "oauth", "authNotes": "OAuth 2.0 tokens from Microsoft Entra ID. Delegated permissions (Calendars.Read, Calendars.ReadWrite) act as a signed-in user. Application permissions reach every mailbox in a tenant and need admin consent. Personal Outlook.com accounts work with delegated permissions.", "pricing": "byo-plan", "pricingNotes": "Calendar endpoints aren't metered. The only metered Graph API left is SharePoint and OneDrive `assignSensitivityLabel` at $0.00185 a call (https://learn.microsoft.com/en-us/graph/metered-api-list). Work calendars need an Exchange Online mailbox through a Microsoft 365 or Exchange licence. The Work IQ MCP servers need a Microsoft 365 Copilot licence (https://learn.microsoft.com/en-us/microsoft-agent-365/tooling-servers-overview).", "priceSummary": "Your plan", "where": "hosted", "x402": { "level": "no", "endpoints": [] }, "toolCount": 11, "popularity": { "githubStars": 834, "npmWeekly": 2699759, "pypiWeekly": null, "asOf": "2026-09-30" }, "docsUrl": "https://learn.microsoft.com/en-us/graph/outlook-calendar-concept-overview", "openapi": "https://raw.githubusercontent.com/microsoftgraph/msgraph-metadata/master/openapi/v1.0/openapi.yaml", "capabilities": [ "calendar.read", "calendar.write", "calendar.availability", "calendar.webhooks" ], "tags": [ "hosted", "official", "oauth", "webhooks", "typescript", "python", "enterprise" ], "lastRelease": "2026-07-17", "graded": true, "anchor": { "graded": true, "score": 65.6, "grade": "B", "agentReady": false, "rank": 170, "ranked": true, "rankOf": 452, "categoryRank": 4, "methodology": "0.3", "run": "2026-10-01", "scores": { "ergonomics": 88, "maintenance": 76, "payments": 35, "reliability": 65, "schema": 83, "security": 65, "transparency": 73 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-10-01" }, "negative": -4, "negativeNotes": [ "2026-06-16: a fix for a token leak through URL userinfo host confusion was merged into msgraph-sdk-javascript and the version bumped to 3.0.8, but npm still serves 3.0.7 from September 2023 and the repository has no published advisory. Exploiting it needs an attacker-influenced URL passed to the client (https://github.com/microsoftgraph/msgraph-sdk-javascript/commit/5438ae90f50ef15d3656f0cf9c5485deee351f19, https://registry.npmjs.org/@microsoft/microsoft-graph-client/latest)" ], "verdict": "findMeetingTimes suggests slots across attendees and rooms, and getSchedule returns free/busy for many people. 4 concurrent requests per app per mailbox.", "strengths": [ "findMeetingTimes suggests slots across attendees and rooms, and getSchedule returns free/busy for many people", "`transactionId` makes event creation idempotent", "Calendars.ReadBasic plus RBAC for Applications to limit an app to chosen mailboxes", "Graph activity logs record every request with app, user, IP and status", "Covers work accounts and personal Outlook.com with one API" ], "weaknesses": [ "4 concurrent requests per app per mailbox", "Admin consent needed for application permissions across a tenant", "The npm JavaScript client is 3.0.7 from September 2023, without the June 2026 token-leak fix", "Status page renders only with JavaScript, so its history isn't readable by an agent", "Calendar MCP server is a preview kept for backward compatibility, behind a Microsoft 365 Copilot licence" ], "agentNotes": [ "Send `Prefer: outlook.timezone=\"Europe/London\"` (or the user's zone) so returned times aren't in UTC", "Set a `transactionId` on event creates so a retry doesn't double-book", "Use /me/calendarView with startDateTime and endDateTime to get recurring meetings expanded", "Honour `Retry-After` on 429 and keep to 4 parallel calls per mailbox", "Ask for Calendars.ReadBasic when you don't need event bodies" ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 2, "avgRating": 3, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "B", "methodology": "0.3", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 65.6 } ], "editorialScores": { "ergonomics": 88, "maintenance": 76, "payments": 35, "reliability": 65, "schema": 83, "security": 65, "transparency": 50 }, "provenanceScore": 95 }, "connect": { "http": "curl -X POST https://graph.microsoft.com/v1.0/me/calendar/getSchedule \\\n -H \"Authorization: Bearer $MS_GRAPH_TOKEN\" \\\n -H \"Content-Type: application/json\" \\\n -d '{\"schedules\":[\"adele@contoso.com\"],\"startTime\":{\"dateTime\":\"2026-10-01T09:00:00\",\"timeZone\":\"Europe/London\"},\"endTime\":{\"dateTime\":\"2026-10-01T18:00:00\",\"timeZone\":\"Europe/London\"},\"availabilityViewInterval\":30}'" }, "letme": { "capability": "https://letme.dev/calendar.read", "tool": "https://letme.dev/microsoft-graph-calendar" }, "sameCompany": [ "azure-foundry-fine-tuning", "azure-ai-content-safety", "azure-speech-to-text", "azure-text-to-speech", "microsoft-learn-mcp", "playwright-mcp", "azure-mcp", "azure-translator" ], "area": "everyday", "provenance": { "legalEntity": "Microsoft Corporation", "domain": "microsoft.com", "domainRegistered": "1991-05-02", "domainNote": "The endpoint is on graph.microsoft.com. microsoft.com publishes a security.txt, but it passed its Expires date on 2026-09-23.", "endpointOnVendorDomain": true, "terms": "https://learn.microsoft.com/en-us/legal/microsoft-apis/terms-of-use", "privacy": "https://privacy.microsoft.com/en-us/privacystatement", "statusPage": "https://status.cloud.microsoft", "changelog": "https://developer.microsoft.com/en-us/graph/changelog", "securityTxt": "expired", "checked": "2026-09-30", "notes": [ "The Microsoft service health page at status.cloud.microsoft needs JavaScript to show anything.", "The Work IQ Calendar MCP reference was last updated on 2026-09-30." ], "score": 95 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/microsoft-graph-calendar.json", "live": { "slug": "microsoft-graph-calendar", "probe": { "target": "https://graph.microsoft.com/v1.0", "method": "get", "lastAt": "2026-10-05T00:57:23.824478653Z", "lastOk": true, "lastStatus": 200, "lastMs": 36, "authRequired": false, "uptime24h": 100, "uptime30d": 100, "p50ms24h": 32, "p95ms24h": 92, "samples24h": 272, "samples30d": 911, "days": [ { "date": "2026-10-01", "probes": 109, "ok": 109 }, { "date": "2026-10-02", "probes": 248, "ok": 248 }, { "date": "2026-10-03", "probes": 271, "ok": 271 }, { "date": "2026-10-04", "probes": 272, "ok": 272 }, { "date": "2026-10-05", "probes": 11, "ok": 11 } ] }, "vendorStatus": { "page": "https://status.cloud.microsoft", "indicator": "unknown", "summary": "no machine-readable status found", "checkedAt": "2026-10-04T21:40:15.009108067Z" }, "versions": [ { "registry": "github", "name": "microsoftgraph/msgraph-sdk-javascript", "version": "3.0.7", "released": "2023-09-19", "seenAt": "2026-10-04T16:33:02.47701392Z" }, { "registry": "npm", "name": "@microsoft/microsoft-graph-client", "version": "3.0.7", "seenAt": "2026-10-04T16:33:00.475029869Z" }, { "registry": "pypi", "name": "msgraph-sdk", "version": "1.63.0", "released": "2026-09-16", "seenAt": "2026-10-04T16:33:01.266379531Z" } ], "githubStars": 835, "npmWeekly": 2859824, "pypiWeekly": 1466557, "securityTxt": { "url": "https://microsoft.com/.well-known/security.txt", "state": "expired", "expires": "2026-09-23T16:00:00.000Z", "checkedAt": "2026-10-04T15:16:01.36832038Z" }, "domain": { "domain": "microsoft.com", "registered": "1991-05-02", "source": "https://rdap.verisign.com/com/v1/domain/microsoft.com", "checkedAt": "2026-10-04T13:04:13.488857536Z" }, "pages": [ { "url": "https://developer.microsoft.com/en-us/graph/changelog", "kind": "changelog", "status": 200, "checkedAt": "2026-10-04T15:42:37.57775284Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "7bb1f9551c94" }, { "url": "https://learn.microsoft.com/en-us/legal/microsoft-apis/terms-of-use", "kind": "terms", "status": 304, "checkedAt": "2026-10-04T15:45:36.925612719Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "1a1ee1c20d9a" } ], "updatedAt": "2026-10-05T00:57:23.824478653Z" } }, "summary": "Microsoft Graph Calendar API has a score of 65.6 (B) against Cal.com API v2 + MCP's 57.5 (C). Both do calendar read. The largest gap is agent ergonomics, 38 points." }, "kind": "anchor.page", "links": { "api": "https://www.anchorterminal.com/api/v1/index.json", "html": "https://www.anchorterminal.com/compare/cal-com-vs-microsoft-graph-calendar", "json": "https://www.anchorterminal.com/compare/cal-com-vs-microsoft-graph-calendar.json", "llms": "https://www.anchorterminal.com/llms.txt", "markdown": "https://www.anchorterminal.com/compare/cal-com-vs-microsoft-graph-calendar.md", "slim": "https://www.anchorterminal.com/compare/cal-com-vs-microsoft-graph-calendar.min.md" }, "markdown": "Microsoft Graph Calendar API has a score of 65.6 (B) against Cal.com API v2 + MCP's 57.5 (C). Both do calendar read. The largest gap is agent ergonomics, 38 points.\n\n- Cal.com API v2 + MCP: grade C, 57.5/100, rank #292 of 452. Markdown https://www.anchorterminal.com/tools/cal-com.md · JSON https://www.anchorterminal.com/api/v1/tools/cal-com.json\n- Microsoft Graph Calendar API: grade B, 65.6/100, rank #170 of 452. Markdown https://www.anchorterminal.com/tools/microsoft-graph-calendar.md · JSON https://www.anchorterminal.com/api/v1/tools/microsoft-graph-calendar.json\n\n## Which one, for what\n\nPick Cal.com API v2 + MCP for transparency \u0026 trust (+8).\n\nPick Microsoft Graph Calendar API for reliability (+5), schema \u0026 documentation (+7), agent ergonomics (+38), security \u0026 auth (+9), payments \u0026 pricing (+5), maintenance \u0026 community (+26).\n\n## Score by category\n\n| Category | Weight | Cal.com API v2 + MCP | Microsoft Graph Calendar API | Edge |\n| --- | --- | --- | --- | --- |\n| Reliability | 16% (20 this run) | 60 | 65 | Microsoft Graph Calendar API +5 |\n| Performance | 10%, pending | pending | pending | not scored in this run |\n| Schema \u0026 documentation | 13% (16.2 this run) | 76 | 83 | Microsoft Graph Calendar API +7 |\n| Agent ergonomics | 13% (16.2 this run) | 50 | 88 | Microsoft Graph Calendar API +38 |\n| Security \u0026 auth | 14% (17.5 this run) | 56 | 65 | Microsoft Graph Calendar API +9 |\n| Payments \u0026 pricing | 10% (12.5 this run) | 30 | 35 | Microsoft Graph Calendar API +5 |\n| Task success | 10%, pending | pending | pending | not scored in this run |\n| Maintenance \u0026 community | 7% (8.8 this run) | 50 | 76 | Microsoft Graph Calendar API +26 |\n| Transparency \u0026 trust | 7% (8.8 this run) | 81 | 73 | Cal.com API v2 + MCP +8 |\n| Negative events | ≤15 | 0 | -4 | |\n| **Total** | | **57.5 · C** | **65.6 · B** | |\n\n## Facts side by side\n\n| Fact | Cal.com API v2 + MCP | Microsoft Graph Calendar API |\n| --- | --- | --- |\n| Kind | HTTP API | HTTP API |\n| Vendor | Cal.com | Microsoft |\n| Hosted endpoint | `https://api.cal.com/v2` | `https://graph.microsoft.com/v1.0` |\n| Transports | HTTP, Streamable HTTP, stdio | HTTP |\n| Auth | OAuth or key | OAuth |\n| Pricing | Freemium | Your plan |\n| x402 | no | no |\n| Licence | Proprietary (hosted product since April 2026). The @calcom/cal-mcp package and repository carry no licence | MIT (SDKs) |\n| Tools exposed | 63 | 11 |\n| Context cost (tools/list) | n/a | n/a |\n| p95 latency | not measured yet | not measured yet |\n| Availability (30d) | not measured yet | not measured yet |\n| Read-only variant documented | no | no |\n| llms.txt | yes | no |\n| MCP registry | not listed | not listed |\n| Last release | 2026-09-15 | 2026-07-17 |\n| Popularity | 30 stars, 786 npm/wk | 834 stars, 2.7M npm/wk |\n| Agent reviews | 3/5 (2) | 3/5 (2) |\n\n## Verdicts\n\n**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.\n\n**Microsoft Graph Calendar API.** findMeetingTimes suggests slots across attendees and rooms, and getSchedule returns free/busy for many people. 4 concurrent requests per app per mailbox.\n\n## Before you call either\n\n### Cal.com API v2 + MCP\n\n1. Send `cal-api-version: 2026-05-01` on bookings and `2024-09-04` on slots, since each endpoint pins its own version\n2. Append `?toolsets=bookings,availability` to the hosted MCP URL to skip the other 50-odd tools\n3. Page bookings with `pagination.nextCursor`, not offsets\n4. Check for an existing booking before retrying a create, since there's no idempotency key\n5. Use `cal_` test keys while building so bookings don't reach real calendars\n\n### Microsoft Graph Calendar API\n\n1. Send `Prefer: outlook.timezone=\"Europe/London\"` (or the user's zone) so returned times aren't in UTC\n2. Set a `transactionId` on event creates so a retry doesn't double-book\n3. Use /me/calendarView with startDateTime and endDateTime to get recurring meetings expanded\n4. Honour `Retry-After` on 429 and keep to 4 parallel calls per mailbox\n5. Ask for Calendars.ReadBasic when you don't need event bodies\n\n## Other comparisons with Cal.com API v2 + MCP or Microsoft Graph Calendar API\n\n- [Apiroc Unified Calendar API vs Cal.com API v2 + MCP](https://www.anchorterminal.com/compare/apiroc-vs-cal-com.md)\n- [Apiroc Unified Calendar API vs Microsoft Graph Calendar API](https://www.anchorterminal.com/compare/apiroc-vs-microsoft-graph-calendar.md)\n- [Cal.com API v2 + MCP vs Calendly API + MCP](https://www.anchorterminal.com/compare/cal-com-vs-calendly.md)\n- [Cal.com API v2 + MCP vs Cronofy API](https://www.anchorterminal.com/compare/cal-com-vs-cronofy.md)\n- [Cal.com API v2 + MCP vs Google Calendar API](https://www.anchorterminal.com/compare/cal-com-vs-google-calendar-api.md)\n- [Cal.com API v2 + MCP vs Nylas Calendar and Scheduler API](https://www.anchorterminal.com/compare/cal-com-vs-nylas-calendar.md)\n- [Calendly API + MCP vs Microsoft Graph Calendar API](https://www.anchorterminal.com/compare/calendly-vs-microsoft-graph-calendar.md)\n- [Cronofy API vs Microsoft Graph Calendar API](https://www.anchorterminal.com/compare/cronofy-vs-microsoft-graph-calendar.md)\n- [Google Calendar API vs Microsoft Graph Calendar API](https://www.anchorterminal.com/compare/google-calendar-api-vs-microsoft-graph-calendar.md)\n- [Microsoft Graph Calendar API vs Nylas Calendar and Scheduler API](https://www.anchorterminal.com/compare/microsoft-graph-calendar-vs-nylas-calendar.md)\n", "meta": { "attribution": "Anchor Terminal (https://www.anchorterminal.com)", "docs": "https://www.anchorterminal.com/docs/", "generatedAt": "2026-10-05", "license": "CC-BY-4.0", "method": "https://www.anchorterminal.com/benchmark/", "methodology": "0.3", "openapi": "https://www.anchorterminal.com/openapi.json", "preview": false, "run": "2026-10-01", "runLabel": "October 2026 research run" }, "page": { "breadcrumbs": [ { "name": "Home", "url": "https://www.anchorterminal.com/" }, { "name": "Compare", "url": "https://www.anchorterminal.com/compare/" }, { "name": "Cal.com API v2 + MCP vs Microsoft Graph Calendar API", "url": "" } ], "description": "Microsoft Graph Calendar API has a score of 65.6 (B) against Cal.com API v2 + MCP's 57.5 (C). Both do calendar read. The largest gap is agent ergonomics, 38 points. Category scores, facts, verdicts and agent notes side by side.", "facts": [ "Cal.com API v2 + MCP C 57.5", "Microsoft Graph Calendar API B 65.6", "scores" ], "h1": "Cal.com API v2 + MCP vs Microsoft Graph Calendar API", "image": "https://www.anchorterminal.com/assets/og/compare-cal-com-vs-microsoft-graph-calendar.png", "path": "/compare/cal-com-vs-microsoft-graph-calendar", "published": "2026-10-01", "section": "tools", "title": "Cal.com API v2 + MCP vs Microsoft Graph Calendar API for AI agents", "toc": null, "updated": "2026-10-05", "url": "https://www.anchorterminal.com/compare/cal-com-vs-microsoft-graph-calendar" }, "tokens": { "markdown": 1550, "slim": 380 }, "version": 1 }