Polygonpolygon.io
Polygon's API program has strong discoverability and a solid machine-readable contract — partners and agents can find and parse the surface with confidence. The urgent gaps are in agent understanding and operational usability: AI agents have no instructions file or clear operation-level semantics to build against, runnable examples are absent, and rate-limit and idempotency behaviors are undocumented, all of which force partners to guess their way through integrations.
API DesignA clean, typed, well-governed API contract agents can reason about3 pass2 warn0 fail87A
| Signal | Points | Findings | Rationale | |
|---|---|---|---|---|
| pass | Auth declared & discoverablevia spec | 25/25 | Authentication required (global or on every operation). Investigated: spec 100%, docs 100%. | Agents can only authenticate when auth is declared, scoped, and discoverable. |
| warn | Machine-readable, versioned contractvia spec | 18.8/25 | info.version="1.0.0" 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 | High parameter complexity (avg 13.5 params/op + nested params). Investigated: spec 67%, sdk 53%. | 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 0%. | 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%. | 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 pass0 warn1 fail81A
| Signal | Points | Findings | Rationale | |
|---|---|---|---|---|
| pass | Self-service developer portalvia docs | 29/29 | Self-service signup at https://massive.com/dashboard/signup; no free tier or sandbox language detected. Investigated: docs 100%. | Self-serve key/account creation is the fast first call for partners, with no sales gate. |
| pass | Description completenessvia spec | 15/15 | 85% description completeness (target 90%+). Investigated: spec 100%, sdk 98%. | Complete descriptions are the context humans and agents need to use endpoints. |
| fail | Changelog publishedvia spec | 0/13 | No changelog URL or mention found in spec metadata. Investigated: spec 0%, docs 0%, sdk 0%. | A published changelog lets partners track changes without surprise. |
| na | Quickstart present | —/25 | No surface produced evidence for this capability in this run. | A quickstart is the fastest path from landing page to first successful call. |
| na | Code samples in docs | —/18 | No surface produced evidence for this capability in this run. | Multi-language samples shorten time-to-first-call. |
Agent DiscoveryPartners and their agents can find your APIs — llms.txt, registries, crawlable and reachable docs2 pass1 warn0 fail92A+
| Signal | Points | Findings | Rationale | |
|---|---|---|---|---|
| pass | llms.txt present, valid & comprehensivevia docs | 30/30 | llms-full.txt reachable at https://polygon.io/llms-full.txt. Investigated: docs 100%, sdk 0%. | A valid, comprehensive llms.txt is the machine-readable entry point for agents. |
| pass | Registry & SDK presencevia docs | 28/28 | Indexed on Context7 (treythomascodes/polygon-client, 269 snippets). Investigated: docs 100%, cli 100%, sdk 67%. | Listing in MCP registries and publishing SDKs puts the API where agents and their tooling look. |
| warn | Crawlable / AEOvia wellknown | 6/12 | Sitemap present (350 entries) but carries no lastmod values. Investigated: wellknown 50%. | Bots allowed plus a fresh sitemap make docs findable by agent crawlers. |
| na | Docs reachable, not hard auth-gated | —/30 | No surface produced evidence for this capability in this run. | Agents can only index and fetch docs they can reach — past auth gates and over correct HTTP semantics. |
Agent UnderstandingAgents can correctly interpret your APIs — machine-readable errors, consistent descriptions, structured data, parseable docs1 pass0 warn2 fail58D
| Signal | Points | Findings | Rationale | |
|---|---|---|---|---|
| pass | Machine-readable errors (RFC 9457)via docs | 28/28 | Only 3 distinct 4xx/5xx codes documented (plus 3 "default" catch-all responses). Investigated: docs 100%, spec 50%. | RFC 9457 problem details and a documented error-code inventory let agents parse failures without burning tokens. |
| fail | Operation purpose clarityvia spec | 0/25 | 56% of operations are agent-inferable. Investigated: spec 0%. | Agents select the right endpoint from its summary + operationId; clear, named operations make tool-selection reliable — the strongest driver of correct tool choice. |
| 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. |
| na | Agent-navigable, token-efficient docs | —/22 | No surface produced evidence for this capability in this run. | Server-rendered, clean, small-footprint docs are what an agent can cheaply fetch and parse correctly. |
| na | Docs structured data | —/8 | No surface produced evidence for this capability in this run. | 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. |
| na | Description consistency across surfaces | —/7 | Only 0 surface description(s) with ≥6 tokens available; need at least 2 to compare. | Every surface tells the same story about what the product is. |
Agent UsabilityAgents have the context to use your APIs reliably, not just find them1 pass1 warn3 fail51D
| Signal | Points | Findings | Rationale | |
|---|---|---|---|---|
| pass | Pagination documented & consistentvia docs | 22/22 | Pagination params detected on 82 list endpoint(s). Investigated: docs 100%, sdk 100%, spec 75%. | Consistent, documented pagination lets agents traverse collections. |
| warn | Sandbox separationvia sdk | 10/20 | No test-mode flag or sandbox environment is exposed. Investigated: sdk 50%. | An isolated environment lets agents exercise destructive operations safely. |
| fail | Idempotency documentedvia sdk | 0/27 | No built-in retry machinery was found; transient failures are not retried. Investigated: 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. |
Resources Discovered
The public resources we found for Polygon — the evidence behind the score. All discovered from public sources; nothing here requires access to your systems.
| Agent hints | Context7 (269) |
|---|---|
| APIs analyzed | 1 — Polygon API |