Loblob.com
Lob's API Design is a relative strength — the contract is machine-readable and auth is well-defined, giving partners a solid technical foundation. txt, no agent instructions file, and no structured data in docs, which means AI agents cannot reliably find, parse, or act on Lob's APIs without human intervention.
API DesignA clean, typed, well-governed API contract agents can reason about2 pass3 warn0 fail76B
| Signal | Points | Findings | Rationale | |
|---|---|---|---|---|
| warn | Machine-readable, versioned contractvia spec | 20.3/25 | info.version="1.0.0" set but no versioning scheme (URL / header / media type) detected. Investigated: spec 81%, docs 63%. | A current OpenAPI version with a declared versioning scheme lets agents reason about the contract. |
| warn | Schema coverage & depthvia sdk | 19.6/25 | 0/24 (0%) enum-like params are realized as constrained types (not bare strings). Investigated: sdk 78%, spec 71%. | 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 spec | 10/10 | 62% example coverage (target 80%+). Investigated: spec 100%, docs 100%, sdk 100%. | Examples carry shape semantics schemas under-specify — for humans and agents alike. |
| warn | Auth declared & discoverablevia docs | 6.3/25 | No securitySchemes declared. Investigated: docs 25%, spec 13%. | Agents can only authenticate when auth is declared, scoped, and discoverable. |
Developer ExperienceThe context both developers and agents need to integrate fast — onboarding, code samples, complete descriptions and worked examples3 pass0 warn2 fail59D
| Signal | Points | Findings | Rationale | |
|---|---|---|---|---|
| pass | Code samples in docsvia docs | 18/18 | Code samples in 10 language(s) across docs (top: shell, curl, typescript); 1/1 pages have ≥ 2 languages on the same page. Investigated: docs 100%. | Multi-language samples shorten time-to-first-call. |
| pass | Description completenessvia spec | 15/15 | 17% description completeness. Investigated: spec 100%, sdk 100%. | Complete descriptions are the context humans and agents need to use endpoints. |
| pass | Changelog publishedvia sdk | 13/13 | Newest official SDK activity 9 day(s) ago. Investigated: sdk 100%, spec 0%, docs 0%. | A published changelog lets partners track changes without surprise. |
| 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 | Quickstart presentvia docs | 0/25 | No quickstart/getting-started page found at the conventional paths. Investigated: docs 0%. | A quickstart is the fastest path from landing page to first successful call. |
Agent DiscoveryPartners and their agents can find your APIs — llms.txt, registries, crawlable and reachable docs1 pass2 warn1 fail65C
| Signal | Points | Findings | Rationale | |
|---|---|---|---|---|
| pass | Registry & SDK presencevia docs | 28/28 | Indexed on Context7 (websites/help_lob_developer-docs, 181 snippets). Investigated: docs 100%, sdk 67%, cli 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 | 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 | 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://docs.lob.com/llms.txt, https://docs.lob.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 docs1 pass3 warn2 fail62C
| Signal | Points | Findings | Rationale | |
|---|---|---|---|---|
| pass | Machine-readable errors (RFC 9457)via docs | 28/28 | No 4xx/5xx response codes (or default error response) documented anywhere in the spec. Investigated: docs 100%, sdk 100%, spec 50%. | RFC 9457 problem details and a documented error-code inventory let agents parse failures without burning tokens. |
| warn | Operation purpose clarityvia spec | 12.5/25 | 21% of operations are agent-inferable. Investigated: spec 50%. | 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 | 11/22 | No pages support .md URLs (0/1 tested). Investigated: docs 50%. | 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 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 fail66C
| Signal | Points | Findings | Rationale | |
|---|---|---|---|---|
| pass | Idempotency documentedvia sdk | 27/27 | Built-in retry machinery is present (grep-derived). Investigated: sdk 100%, spec 0%, docs 0%. | Documented idempotency lets agents retry safely. |
| pass | Sandbox separationvia spec | 20/20 | Test credentials signaled (test-key prefixes) but no sandbox server declared in spec. Investigated: spec 100%, docs 100%, sdk 100%. | An isolated environment lets agents exercise destructive operations safely. |
| warn | Rate-limit signalingvia spec | 5.5/22 | No rate-limit response headers documented. Investigated: spec 25%, docs 25%. | Machine-readable rate-limit headers let agents throttle adaptively. |
| 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 | Pagination documented & consistentvia spec | 0/22 | 2 list endpoint(s) exist but no pagination params found. Investigated: spec 0%, docs 0%. | Consistent, documented pagination lets agents traverse collections. |
Resources Discovered
The public resources we found for Lob — the evidence behind the score. All discovered from public sources; nothing here requires access to your systems.
| Agent hints | Context7 (181) |
|---|---|
| APIs analyzed | 4 — Lob, USPS Web Tools: Track and Confirm API, USPS Web Tools: Address Validation, USPS Web Tools: Domestic Mail Service Collections |