seo-ai-discovery (M21 — AI discovery & agent endpoints)

Discovery files tell agents and coding assistants where to look; none of them is a documented answer-engine ranking or citation signal, so every M21 finding is speculative or directional and the module's weight is 0. Robots/UA posture lives in seo-ai-crawlers (M14); agentic-commerce readiness (UCP + catalog feeds on stores) lives in seo-ecommerce (M18).

Inputs

Work from the PageSnapshot named in your dispatch envelope: <run_dir>/site/discovery.json holds the probe results (status, content-type, bytes, raw bodies ≤256 KB) for /llms.txt, /llms-full.txt, /agents.md, /.well-known/ucp, /.well-known/ai-catalog.json, /sitemap_agentic_discovery.xml, /api/ucp/mcp; <run_dir>/site/robots.json holds the per-bot verdicts for the robots cross-check; vertical in the envelope decides UCP ownership. Deterministic findings already emitted by audit.mjs are listed in <run_dir>/findings.deterministic.json — do not re-emit those ids; add model-judged findings only. If invoked directly with a URL/path and no snapshot exists, first run node "${CLAUDE_PLUGIN_ROOT}/scripts/snapshot.mjs" <target> --out "${CLAUDE_PLUGIN_DATA}/runs" and use the printed snapshot path.

Audits

llms.txt — present (200, text); llmstxt.org structure: one H1 title, optional summary blockquote, H2 sections of - [title](url): note links; linked URLs resolve (--deep, ≤25 checked); the file is not disallowed in robots to the AI bots that would read it. /llms-full.txt is reported present/absent only.
agents.md — present/absent; note when it is a platform default (Shopify ships one) — informational.
UCP profile (/.well-known/ucp) — only when ecommerce is not active (M18 owns it otherwise): public (200, no auth), JSON, ucp.version as YYYY-MM-DD, services/capabilities objects keyed by reverse-DNS names → arrays of {version, spec, transport?, endpoint?, schema}. Note a declared dev.shopify.catalog entry — it says the platform exposes a catalog service, which is a platform default, not a merchant decision.
ARD catalog (/.well-known/ai-catalog.json) — present and parseable JSON. Report-only: v0.9 draft (2026-05-28), near-zero adoption.
Agentic sitemap (/sitemap_agentic_discovery.xml) — present, well-formed XML, sampled <loc> entries resolve.

Fixes

AUTO (fixable: auto), disclosure-gated and scored 0: generate or repair llms.txt / llms-full.txt from the site's own structure (sitemap URLs + parsed titles) only on explicit request (fix --category ai-discovery, alias llms), shown as a diff before writing, always with the disclosure that impact is low/uncertain.
ADVISORY (fixable: advisory): UCP/ARD/agentic-sitemap adoption, and unblocking a disallowed discovery file (the robots write belongs to M14). The tool never authors a merchant profile — platforms generate those.
Never fabricate link targets, descriptions, endpoints, or versions — ask the user or leave a clearly-marked TODO placeholder.