Is substack.com agent ready?
substack.com is partly agent ready: it scores 57/100 (grade C) on the w2agent rubric.
Changed since last check
+1 points since the previous check (2026-09-15)
Fixed: Response time
Category scores
Category breakdown not recorded for this audit.
Agent protocol panel
- A2A agent cardNot found
- OAuth discoveryPresent
- MCP discoveryNot found
- llms.txt validityNot measured
Check results
Bot Accessibility
- ✓No error status codespass
- ✓Response timepass
- ✓XML sitemap existspass
- ✓AI agent accesspass
- ✓Edge treatment of agent user-agentstracked, not scoredpass
- ✓robots.txt existspass
- ✗Content negotiation (Markdown)fail
- —Declared AI usage preferencestracked, not scoredskip
Structured Data
- ✓OpenGraph meta tagspass
- ~Semantic HTML elementspartial
- ✓Appropriate Schema.org typepass
- ✓JSON-LD validpass
- ✗Heading hierarchyfail
- ~Schema.org JSON-LD presentpartial
- ~Schema.org completenesspartial
Content Quality
- ✓FAQ contentpass
- ✓Answer-first contentpass
- ✓Content lengthpass
- ✓Token efficiency (HTML-to-text ratio)pass
- ✗Freshness signalsfail
- ✓Author attributionpass
- ✓Citation readinesspass
- ✓Lists and tables for structured infopass
Agent Discovery
- —llms.txt follows specskip
- ✗llms.txt existsfail
- —MCP server cardtracked, not scoredskip
- ✗Markdown alternate linksfail
- ✗/.well-known/agent-card.jsonfail
- —llms.txt links resolveskip
Agent Protocols
- ✗Discoverable API endpointsfail
- ✗MCP endpointfail
- ✗Action schemasfail
- —/.well-known/ucpskip
- ✓Structured formspass
- —WebMCP imperative APItracked, not scoredskip
- —WebMCP declarative APItracked, not scoredskip
- ✓Reachable as Google-Agentpass
- ✓Reachable as ChatGPT-Userpass
- ✓Reachable as Perplexity-Userpass
Agent Auth
- —MCP authorization (401 challenge → protected resource metadata)skip
- ✓PKCE S256 supportpass
- ✗Public API surfacefail
- —Client ID Metadata Documents (bonus)skip
- —OpenAPI specificationskip
- ✗Agent/bot auth documentationfail
- ~OAuth discovery chain (RFC 9728 → RFC 8414)partial
- ~Developer portalpartial
- ✗Scoped API permissionsfail
- —API catalog (RFC 9727)skip
- —Agent operator signing directorytracked, not scoredskip
Technical
- ✓HTTPSpass
- ✓UTF-8 charsetpass
- ✓Canonical URLspass
- ✓Mobile viewportpass
- ✓Content accessible without JSpass
- ~Security headerspartial
Score history
- 57/100 · rubric v3.0
- 56/100 · rubric v3.0
- 40/100 · rubric v2.0
- 40/100 · rubric v2.0
- 38/100 · rubric v2.0
- 38/100 · rubric v2.0
- 37/100 · rubric v2.0