Circlecircle.com
Circle's API design is a genuine strength — the machine-readable contract and schema quality give partners and their agents a solid foundation to build against. md) that would let partners and AI agents find and understand the API without a sales conversation.
API DesignA clean, typed, well-governed API contract agents can reason about3 pass2 warn0 fail97A+
| 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 | Schema coverage & depthvia sdk | 24.8/25 | 17/17 (100%) public params are fully typed (no any/**kwargs). Analyzer confirms all methods have a derivable input schema. Investigated: sdk 99%, spec 76%. | Typed, complete request/response schemas are what make agent function-calling possible. |
| warn | Machine-readable, versioned contractvia spec | 21.5/25 | info.version="1.0.0" set but no versioning scheme (URL / header / media type) detected. Investigated: spec 86%, docs 72%. | A current OpenAPI version with a declared versioning scheme lets agents reason about the contract. |
| 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 spec | 10/10 | 100% example coverage across params + responses. Investigated: spec 100%, sdk 100%. | 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 examples1 pass0 warn2 fail48F
| Signal | Points | Findings | Rationale | |
|---|---|---|---|---|
| pass | Description completenessvia spec | 15/15 | 44% description completeness. Investigated: spec 100%, sdk 100%. | Complete descriptions are the context humans and agents need to use endpoints. |
| fail | Self-service developer portalvia docs | 0/29 | No signup page detected across conventional paths (/signup, /sign-up, /register, /get-started, /console/signup, /dashboard/signup, /try, /try-free, /free, /free-trial, /start, /start-free). Investigated: docs 0%. | Self-serve key/account creation is the fast first call for partners, with no sales gate. |
| fail | Changelog publishedvia spec | 0/13 | No changelog URL or mention found in spec metadata. Investigated: spec 0%, docs 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 docs1 pass1 warn1 fail60C
| Signal | Points | Findings | Rationale | |
|---|---|---|---|---|
| pass | Registry & SDK presencevia docs | 28/28 | Indexed on Context7 (rsta2/circle, 216 snippets). Investigated: docs 100%, wellknown 100%, sdk 92%, cli 0%, mcp 0%. | Listing in MCP registries and publishing SDKs puts the API where agents and their tooling look. |
| warn | Crawlable / AEOvia wellknown | 6/12 | Sitemap present (2432 entries) but carries no lastmod values. Investigated: wellknown 50%. | Bots allowed plus a fresh sitemap make docs findable by agent crawlers. |
| fail | llms.txt present, valid & comprehensivevia docs | 0/30 | No /llms-full.txt found at the candidate origins. Investigated: docs 0%, sdk 0%. | A valid, comprehensive llms.txt is the machine-readable entry point for agents. |
| 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 docs0 pass2 warn1 fail68C
| Signal | Points | Findings | Rationale | |
|---|---|---|---|---|
| warn | Operation purpose clarityvia spec | 23.6/25 | 86% of operations are agent-inferable (target 90%+). Investigated: spec 94%. | Agents select the right endpoint from its summary + operationId; clear, named operations make tool-selection reliable — the strongest driver of correct tool choice. |
| warn | Machine-readable errors (RFC 9457)via sdk | 14/28 | Single base error "null" present, but only 1 subclass found; a richer hierarchy lets consumers catch narrowly. Investigated: sdk 50%, spec 0%, docs 0%. | RFC 9457 problem details and a documented error-code inventory let agents parse failures without burning tokens. |
| 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 1 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 them2 pass1 warn2 fail62C
| Signal | Points | Findings | Rationale | |
|---|---|---|---|---|
| pass | Idempotency documentedvia sdk | 27/27 | Built-in retry machinery is present (grep-derived). Investigated: sdk 100%, spec 39%, docs 39%. | Documented idempotency lets agents retry safely. |
| pass | Sandbox separationvia sdk | 20/20 | Sandbox environments are exposed (sandbox). Investigated: sdk 100%, spec 0%, docs 0%. | An isolated environment lets agents exercise destructive operations safely. |
| warn | Runnable collection with test scriptsvia platform | 4.5/9 | No test scripts found in the workspace's collections. Investigated: platform 50%. | A public, maintained collection with assertions is runnable truth agents validate against. |
| 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 | Pagination documented & consistentvia spec | 0/22 | No pagination on list endpoints. Investigated: spec 0%, docs 0%. | Consistent, documented pagination lets agents traverse collections. |
Resources Discovered
The public resources we found for Circle — the evidence behind the score. All discovered from public sources; nothing here requires access to your systems.
| Agent hints | Context7 (216) |
|---|---|
| APIs analyzed | 9 — Programmable Wallets, CPN OFI, Core Functionality, Crypto Payouts API, Smart Contract Platform, API Overview, Accounts API, USDC Access, Getting Started with Smart Contract Accounts |