Calendlycalendly.com
Calendly's API Design is a genuine strength — the contract is clean and machine-readable, giving partners a solid foundation to build against. However, two areas are holding the partner program back: Agent Usability is critically weak, meaning partners and their AI agents cannot reliably run real workflows (missing runnable examples, no idempotency guidance, and no rate-limit signaling), and Agent Understanding is inconsistent, with gaps in structured docs, agent instruction files, and parseable context that prevent AI agents from acting on the API without guessing.
API DesignA clean, typed, well-governed API contract agents can reason about3 pass2 warn0 fail87A
| Signal | Points | Findings | Rationale | |
|---|---|---|---|---|
| pass | Auth declared & discoverablevia docs | 25/25 | authentication documented in the docs site at https://developer.calendly.com/authentication. Investigated: docs 100%, wellknown 100%, spec 50%. | Agents can only authenticate when auth is declared, scoped, and discoverable. |
| warn | Machine-readable, versioned contractvia spec | 18.8/25 | info.version="2.0.0" set but no versioning scheme (URL / header / media type) detected. Investigated: spec 75%, docs 50%. | A current OpenAPI version with a declared versioning scheme lets agents reason about the contract. |
| warn | Schema coverage & depthvia spec | 16.7/25 | 90% of operations have documented schemas (target 95%+). Investigated: spec 67%, sdk 67%. | Typed, complete request/response schemas are what make agent function-calling possible. |
| pass | Security & governance hygienevia spec | 15/15 | No credential-shaped strings detected in spec. Investigated: spec 100%, wellknown 100%. | No leaked secrets, no critical lint violations, no OWASP API Top-10 spec smells, and a published vulnerability-disclosure channel. |
| pass | Example coveragevia sdk | 10/10 | README is present and includes a runnable quickstart. Investigated: sdk 100%, spec 0%, docs 0%. | Examples carry shape semantics schemas under-specify — for humans and agents alike. |
Developer ExperienceThe context both developers and agents need to integrate fast — onboarding, code samples, complete descriptions and worked examples2 pass1 warn2 fail55D
| Signal | Points | Findings | Rationale | |
|---|---|---|---|---|
| pass | Description completenessvia spec | 15/15 | 97% of operations + parameters have substantive descriptions. Investigated: spec 100%, sdk 0%. | Complete descriptions are the context humans and agents need to use endpoints. |
| pass | Changelog publishedvia spec | 13/13 | changelog documented in the docs site at https://developer.calendly.com/release-notes. Investigated: spec 100%, docs 100%. | A published changelog lets partners track changes without surprise. |
| warn | Quickstart presentvia docs | 12.5/25 | Quickstart page reachable (10 variants scanned starting at https://developer.calendly.com/quickstart) but no runnable code sample detected in HTML or .md variant. Investigated: docs 50%. | A quickstart is the fastest path from landing page to first successful call. |
| fail | Self-service developer portalvia docs | 0/29 | Signup page is sales-gated (contact-sales/request-access language detected). Investigated: docs 0%. | Self-serve key/account creation is the fast first call for partners, with no sales gate. |
| fail | Code samples in docsvia docs | 0/18 | No detectable code samples across 1 sampled docs pages. Investigated: docs 0%. | Multi-language samples shorten time-to-first-call. |
Agent DiscoveryPartners and their agents can find your APIs — llms.txt, registries, crawlable and reachable docs1 pass3 warn0 fail69C
| Signal | Points | Findings | Rationale | |
|---|---|---|---|---|
| pass | Registry & SDK presencevia docs | 28/28 | Indexed on Context7 (websites/developer_calendly, 1007 snippets). Investigated: docs 100%, sdk 92%, cli 0%, mcp 0%, wellknown 0%. | Listing in MCP registries and publishing SDKs puts the API where agents and their tooling look. |
| warn | Docs reachable, not hard auth-gatedvia docs | 15/30 | 34 of 34 pages return 200 for non-existent URLs (soft 404). Investigated: docs 50%. | Agents can only index and fetch docs they can reach — past auth gates and over correct HTTP semantics. |
| warn | llms.txt present, valid & comprehensivevia docs | 10/30 | No llms.txt found at any candidate location (https://developer.calendly.com/llms.txt, https://developer.calendly.com/docs/llms.txt). Investigated: docs 33%, sdk 0%. | A valid, comprehensive llms.txt is the machine-readable entry point for agents. |
| warn | Crawlable / AEOvia wellknown | 9/12 | Sitemap present (34 entries) but carries no lastmod values. Investigated: wellknown 75%. | Bots allowed plus a fresh sitemap make docs findable by agent crawlers. |
Agent UnderstandingAgents can correctly interpret your APIs — machine-readable errors, consistent descriptions, structured data, parseable docs2 pass2 warn2 fail72B
| Signal | Points | Findings | Rationale | |
|---|---|---|---|---|
| pass | Machine-readable errors (RFC 9457)via docs | 28/28 | 7 distinct 4xx/5xx response codes documented. Investigated: docs 100%, spec 50%. | RFC 9457 problem details and a documented error-code inventory let agents parse failures without burning tokens. |
| pass | Operation purpose clarityvia spec | 25/25 | 93% of operations have a clear summary + operationId an agent can select on. Investigated: spec 100%. | Agents select the right endpoint from its summary + operationId; clear, named operations make tool-selection reliable — the strongest driver of correct tool choice. |
| warn | Agent-navigable, token-efficient docsvia docs | 12.6/22 | 1 of 34 pages appear to be client-side rendered SPA shells (___gatsby detected); agents using HTTP fetches will see no content; 1 more have page structure but little substantive content. Investigated: docs 57%. | Server-rendered, clean, small-footprint docs are what an agent can cheaply fetch and parse correctly. |
| warn | Description consistency across surfaces | 0.4/7 | Mean pairwise description similarity across 2 surfaces (spec, docs) is 2% (threshold 35% for full credit). | Every surface tells the same story about what the product is. |
| fail | Agent instructions file (AGENTS.md)via wellknown | 0/10 | No AGENTS.md at the site root or /.well-known/. Investigated: wellknown 0%. | An AGENTS.md gives coding agents explicit setup, auth, and usage instructions to interpret and operate the API — beyond llms.txt's link index. |
| fail | Docs structured datavia docs | 0/8 | Neither JSON-LD nor OpenGraph/meta tags detected across 1 sampled pages — likely a CSR-only docs site. Investigated: docs 0%. | Structured data (JSON-LD/schema.org) on docs pages gives agents an unambiguous parse target and is what answer engines cite. Detected on the JS-rendered head (Firecrawl) for a bounded page budget, so JS-injected JSON-LD is now caught; pages we can't render are excluded rather than failed. |
Agent UsabilityAgents have the context to use your APIs reliably, not just find them0 pass1 warn3 fail43F
| Signal | Points | Findings | Rationale | |
|---|---|---|---|---|
| warn | Sandbox separationvia sdk | 10/20 | No test-mode flag or sandbox environment is exposed. Investigated: sdk 50%, spec 0%, docs 0%. | An isolated environment lets agents exercise destructive operations safely. |
| fail | Idempotency documentedvia spec | 0/27 | 0% of mutating operations document idempotency. Investigated: spec 0%, docs 0%, sdk 0%. | Documented idempotency lets agents retry safely. |
| fail | Rate-limit signalingvia spec | 0/22 | No rate-limit response headers documented. Investigated: spec 0%, docs 0%. | Machine-readable rate-limit headers let agents throttle adaptively. |
| fail | Runnable collection with test scriptsvia platform | 0/9 | No public Postman workspace discovered for the org. Investigated: platform 0%. | A public, maintained collection with assertions is runnable truth agents validate against. |
| na | Pagination documented & consistent | —/22 | No surface produced evidence for this capability in this run. | Consistent, documented pagination lets agents traverse collections. |
Resources Discovered
The public resources we found for Calendly — the evidence behind the score. All discovered from public sources; nothing here requires access to your systems.
| Agent hints | Context7 (1,007) |
|---|---|
| APIs analyzed | 1 — Calendly API |