{
 "tool": "classify-ua",
 "endpoint": "https://www.pathwren.workers.dev/tools/classify-ua",
 "asked": {
  "ua": "claude-user"
 },
 "summary": "Claude-User — Anthropic (User-triggered fetchers).\nMatched on \"Claude-User\".\n\nWhat it is: Fetches a page because a Claude user asked Claude to read it, at that moment.\n\nCost of blocking it: Claude reports a fetch failure to a user who asked for your page by name.\n\nrobots.txt token: Claude-User · robots.txt: obeys robots.txt (documented) · verification: no published verification method\n\nA user-agent string is a claim, not a proof: anyone can send it. Before you act on a match, check the address with is_verified_crawler_ip, or use the operator's reverse-DNS method where there are no published ranges.",
 "answer": {
  "user_agent": "claude-user",
  "matched": true,
  "matched_on": "Claude-User",
  "crawler": {
   "slug": "claude-user",
   "name": "Claude-User",
   "operator": "Anthropic",
   "operator_slug": "anthropic",
   "category": "user-fetch",
   "category_label": "User-triggered fetchers",
   "robots_token": "Claude-User",
   "user_agent_substring": "Claude-User",
   "user_agent_example": "Mozilla/5.0 (compatible; Claude-User/1.0; +Claude-User@anthropic.com)",
   "respects_robots_txt": "documented",
   "respects_robots_txt_label": "obeys robots.txt (documented)",
   "verification_method": "none",
   "verification_label": "no published verification method",
   "published_ip_ranges_url": null,
   "ip_ranges_endpoint": null,
   "ipv4_prefix_count": 0,
   "ipv6_prefix_count": 0,
   "what_it_is": "Fetches a page because a Claude user asked Claude to read it, at that moment.",
   "cost_of_blocking": "Claude reports a fetch failure to a user who asked for your page by name.",
   "operator_docs": "https://support.anthropic.com/en/articles/8896518",
   "docs_url": "https://www.pathwren.workers.dev/crawler/claude-user.html",
   "json_url": "https://www.pathwren.workers.dev/crawler/claude-user.json",
   "last_reviewed": "2026-09-04"
  },
  "also_matched": [],
  "verification": {
   "method": "none",
   "label": "no published verification method",
   "published_ip_ranges": null,
   "how": "The operator publishes no verification method at all, so this user-agent cannot be verified. Treat it as unverifiable."
  },
  "caveat": "A user-agent string is a claim, not a proof: anyone can send it. Before you act on a match, check the address with is_verified_crawler_ip, or use the operator's reverse-DNS method where there are no published ranges.",
  "source": "https://www.pathwren.workers.dev"
 },
 "answered_by": {
  "note": "The MCP tool itself answered this. One implementation, two doors — this endpoint holds no copy of it.",
  "server": "ai-crawler-index",
  "endpoint": "https://www.pathwren.workers.dev/mcp",
  "tool": "classify_user_agent",
  "protocol": "MCP streamable-http, JSON-RPC 2.0 tools/call"
 },
 "caveats": [
  "A user-agent is a claim, not proof. Pair it with /tools/verify-crawler, which is the address half of the same question."
 ],
 "docs": "https://www.pathwren.workers.dev/tools/classify-ua.html?s=client-dossiers",
 "catalogue": "https://www.pathwren.workers.dev/tools/index.json?s=client-dossiers",
 "more": {
  "who actually crawls this host": "https://www.pathwren.workers.dev/bot/index.html?s=client-dossiers",
  "every named client as one file": "https://www.pathwren.workers.dev/data/observed-clients.json?s=client-dossiers"
 },
 "auth": "none — no account, no key, no handshake. CORS open, cacheable, CC0-1.0.",
 "license": "CC0-1.0",
 "independent": true,
 "_about": {
  "page": "https://www.pathwren.workers.dev/bot/claudebot.html?s=client-dossiers",
  "what": "What this host recorded about the client that made this request — the requests, the status codes and the user-agent string, from its own log. Nothing else: no address is published, nothing is looked up anywhere, and there is no account to close.",
  "matched_on": "the User-Agent header you sent. If we have no page for it yet this points at the index of all of them.",
  "index": "https://www.pathwren.workers.dev/bot/index.html?s=client-dossiers"
 }
}