# postmarkapp.com: agentic web grade A+

Score 62 (coverage 40 + breadth 12 + conformance 10); 6 standards observed across 4 of 9 steps; checked 2026-10-25T03:29:37Z. This grades the agent-facing files published at postmarkapp.com, not the organisation's products.

## Manifests

| Manifest | Path | Result | Errors | Warnings |
| --- | --- | --- | --- | --- |
| Agentic Resource Discovery | /.well-known/ard.json | absent HTTP 404 |  |  |
| AI Catalog well-known file | /.well-known/ai-catalog.json | valid |  | served only at deprecated /.well-known/ai-catalog.json; ARD v0.91+ expects /.well-known/ard.json (serve both during migration) |
| MCP Server Cards (SEP-2127) | /.well-known/mcp/server-card.json | blocked HTTP 429 |  |  |
| Agent2Agent Protocol | /.well-known/agent-card.json | absent HTTP 404 |  |  |
| llms.txt | /llms.txt | valid |  |  |
| AGENTS.md | /AGENTS.md | absent HTTP 404 |  |  |
| Agent Skills | /.well-known/agent-skills/index.json | valid |  |  |
| api-catalog: A Well-Known URI and Link Relation to Help Discovery of APIs | /.well-known/api-catalog | valid |  |  |
| AI Crawler User-Agent Tokens in robots.txt | /robots.txt | valid |  | no Agentmap: line (optional convention pointing agents at /.well-known/ard.json) |
| security.txt (RFC 9116) | /.well-known/security.txt | absent HTTP 404 |  |  |
| auth.md | /auth.md | errors | none of the auth.md mechanism names found (identity_assertion, service_auth, anonymous) |  |
| Open Knowledge Format | /okf/index.md | blocked HTTP 429 |  |  |

## Standards observed

- llms.txt: https://postmarkapp.com/llms.txt (https://agenticweb.wiki/protocols/llms-txt/)
- Content Signals Policy: https://postmarkapp.com/robots.txt (https://agenticweb.wiki/protocols/cloudflare-content-signals-policy/)
- AI Catalog well-known file: https://postmarkapp.com/.well-known/ai-catalog.json (https://agenticweb.wiki/protocols/ai-catalog-well-known-file/)
- api-catalog: A Well-Known URI and Link Relation to Help Discovery of APIs: https://postmarkapp.com/.well-known/api-catalog (https://agenticweb.wiki/protocols/api-catalog-rfc9727/)
- AI Crawler User-Agent Tokens in robots.txt: https://postmarkapp.com/robots.txt (https://agenticweb.wiki/protocols/ai-crawler-tokens-robots/)
- Agent Skills: https://postmarkapp.com/.well-known/agent-skills/index.json (https://agenticweb.wiki/protocols/anthropic-agent-skills-format/)

## Cheapest next steps

1. Agentic Resource Discovery: a catalog at /.well-known/ard.json lets agents discover your APIs, MCP servers and data in one fetch (https://agenticweb.wiki/protocols/ard/)
2. AGENTS.md: instructions for coding agents working on or with the site (https://agenticweb.wiki/protocols/agents-md/)
3. security.txt (RFC 9116): RFC 9116 contact and expiry, read by agents and people (https://www.rfc-editor.org/rfc/rfc9116)

Published a manifest or spotted a path we missed? Submit at https://agenticweb.wiki/submit/ or email mailto:info@belgravialabs.com?subject=Manifest%20or%20correction%20for%20postmarkapp.com.

## Agent pre-flight & practical readiness

Preferred mode: `openapi` (fallback `agent_skills`). Read the published API description and call those operations. Scraping HTML skips the interface the site already gave you.

Fetch: `GET https://postmarkapp.com/swagger/server.yml` GET the API description and call the documented operations.

Practical readability: exa_parsable no, markdown negotiation no, render `blocked`, HTML quality `blocked`.

AI crawler posture: `waf_challenged` · Assistant access: OpenAI `blocked`, Anthropic `blocked`, Google `blocked`, Perplexity `blocked`, Exa `blocked`.

Readiness subscores: reach 18/20, readability 0/30, capabilities 20/35, conformance 10/15, total 48/100, grade B.

## Rubric

+10 per lifecycle step with a standard observed, counting manifests that validate or that the probe rule for the standard recognises (a valid MCP server card counts for MCP; max 90); +3 per observed standard beyond the first two (max 15); conformance +15 (+10 with one manifest) minus 5 per agent-facing manifest with errors, never below 0 (security.txt is reported, not scored). Lifecycle grade: A+ >= 60, A >= 45, B >= 30, C >= 20, D >= 10. Strict 100-point composite (subscores.total_100 / subscores.grade_100): reach_and_policy (20) + readability (30) + capabilities (35) + conformance (15), where A+ >= 80, A >= 65, B >= 45, C >= 28, D >= 15.

JSON: https://agenticweb.wiki/check/postmarkapp.com/index.json · badge: https://agenticweb.wiki/badge/postmarkapp.com.svg