Uspsusps.com
USPS's API design is a clear strength — the contract is well-structured and machine-readable, giving partners a solid foundation to build against. txt file, structured docs metadata, or an agent-readable front door, partners and their AI agents cannot find or navigate the API without a manual conversation.
API DesignA clean, typed, well-governed API contract agents can reason about2 pass3 warn0 fail91A+
| Signal | Points | Findings | Rationale | |
|---|---|---|---|---|
| warn | Machine-readable, versioned contractvia spec | 24.2/25 | info.version="3.2.9" set but no versioning scheme (URL / header / media type) detected. Investigated: spec 97%, docs 94%. | A current OpenAPI version with a declared versioning scheme lets agents reason about the contract. |
| warn | Auth declared & discoverablevia spec | 22.7/25 | Authentication applied on 2/3 operations (partial coverage). Investigated: spec 91%, docs 81%, wellknown 0%. | Agents can only authenticate when auth is declared, scoped, and discoverable. |
| warn | Schema coverage & depthvia spec | 18.2/25 | Only 67% of operations have documented schemas. Investigated: spec 73%, sdk 25%. | 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 13%, 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 examples3 pass1 warn1 fail75B
| Signal | Points | Findings | Rationale | |
|---|---|---|---|---|
| pass | Self-service developer portalvia docs | 29/29 | Signup page at https://www.usps.com/signup/ (CSR-rendered — body classifier inconclusive); free tier / sandbox documented in pricing/docs. 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 | 83% description completeness (target 90%+). Investigated: spec 100%, sdk 0%. | Complete descriptions are the context humans and agents need to use endpoints. |
| pass | Changelog publishedvia sdk | 13/13 | Newest official SDK activity 8 day(s) ago. Investigated: sdk 100%, spec 0%, docs 0%. | A published changelog lets partners track changes without surprise. |
| warn | Quickstart presentvia docs | 12.5/25 | Quickstart page reachable (1 variants scanned starting at https://developers.usps.com/getting-started) 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 | 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 docs0 pass3 warn1 fail57D
| Signal | Points | Findings | Rationale | |
|---|---|---|---|---|
| warn | Docs reachable, not hard auth-gatedvia docs | 22.5/30 | Server ignores Accept: text/markdown header (0/1 pages return markdown). Investigated: docs 75%. | Agents can only index and fetch docs they can reach — past auth gates and over correct HTTP semantics. |
| warn | Registry & SDK presencevia sdk | 14/28 | No MCP server, tool manifest, or list-tools capability is discoverable (server entrypoint: absent, tool manifest: unknown, list-tools: unknown). Investigated: sdk 50%, docs 0%, cli 0%. | Listing in MCP registries and publishing SDKs puts the API where agents and their tooling look. |
| warn | Crawlable / AEOvia wellknown | 6/12 | No sitemap discoverable via robots.txt or /sitemap.xml on the docs host. 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.txt found at any candidate location (https://developers.usps.com/llms.txt, https://developers.usps.com/docs/llms.txt). Investigated: docs 0%, sdk 0%. | A valid, comprehensive llms.txt is the machine-readable entry point for agents. |
Agent UnderstandingAgents can correctly interpret your APIs — machine-readable errors, consistent descriptions, structured data, parseable docs2 pass2 warn2 fail76B
| Signal | Points | Findings | Rationale | |
|---|---|---|---|---|
| pass | Machine-readable errors (RFC 9457)via docs | 28/28 | 5 distinct 4xx/5xx response codes documented. Investigated: docs 100%, spec 50%, sdk 0%. | RFC 9457 problem details and a documented error-code inventory let agents parse failures without burning tokens. |
| pass | Operation purpose clarityvia spec | 25/25 | 100% 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 | 17.3/22 | No pages support .md URLs (0/1 tested). Investigated: docs 79%. | Server-rendered, clean, small-footprint docs are what an agent can cheaply fetch and parse correctly. |
| warn | Description consistency across surfaces | 0.6/7 | Mean pairwise description similarity across 2 surfaces (spec, docs) is 3% (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 assessed pages (1 JS-rendered). 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 them2 pass2 warn1 fail65C
| Signal | Points | Findings | Rationale | |
|---|---|---|---|---|
| pass | Pagination documented & consistentvia spec | 22/22 | Pagination params detected on 2 list endpoint(s). Investigated: spec 100%, docs 100%. | Consistent, documented pagination lets agents traverse collections. |
| pass | Sandbox separationvia spec | 20/20 | Sandbox server declared but no distinguishable test credentials in scheme descriptions. Investigated: spec 100%, docs 100%, sdk 50%. | An isolated environment lets agents exercise destructive operations safely. |
| warn | Rate-limit signalingvia spec | 11/22 | Only 1 rate-limit header(s) documented. Investigated: spec 50%, docs 50%. | Machine-readable rate-limit headers let agents throttle adaptively. |
| warn | Idempotency documentedvia spec | 2.3/27 | 0% of mutating operations document idempotency. Investigated: spec 8%, docs 8%, sdk 0%. | Documented idempotency lets agents retry safely. |
| 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 Usps — the evidence behind the score. All discovered from public sources; nothing here requires access to your systems.
| APIs analyzed | 8 — Labels, Subscriptions - Tracking, Domestic Prices, International Prices, Addresses, Locations, Open Authorization (OAuth 2.0) 3.0, Package Tracking and Notification |
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