{"name":"crawler-ip-verifier","title":"Crawler IP Verifier — MCP server","version":"1.0.0","transport":"streamable-http","transport_docs":"https://www.pathwren.workers.dev/mcp-transport.html","endpoint":"https://www.pathwren.workers.dev/mcp/netcheck","protocol_versions":["2026-07-28","2025-11-25","2025-06-18","2025-03-26","2024-11-05"],"stateless":true,"auth":"none — public, read-only, no key, no rate limit","what_it_is":"Address and prefix work against the operator-published IP ranges this host mirrors: batch verification of up to 500 addresses, containment and overlap arithmetic on a CIDR, paste-ready firewall allowlists in eight formats, per-crawler verification methods, and the mirror's own freshness.","different_from":"https://www.pathwren.workers.dev/mcp answers one address with a boolean. This server is the batch, the prefix arithmetic and the artifact: different input shapes, different outputs, and it is the one to call from a script. https://www.pathwren.workers.dev/mcp/triage does the same identification starting from log LINES rather than addresses.","try_it":"curl -s https://www.pathwren.workers.dev/mcp/netcheck -H 'content-type: application/json' -H 'accept: application/json, text/event-stream' -d '{\"jsonrpc\":\"2.0\",\"id\":1,\"method\":\"tools/call\",\"params\":{\"name\":\"verify_batch\",\"arguments\":{\"addresses\":[\"20.171.206.1\",\"203.0.113.9\"]}}}'","data_behind_it":"https://www.pathwren.workers.dev/ip-ranges/all.json","reverse_dns":"documented per crawler, never performed — this server makes no outbound request","call_this_first":{"tool":"no_arguments_report_the_crawler_ip_ranges_this_host_mirrors","takes_arguments":false,"body":{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"no_arguments_report_the_crawler_ip_ranges_this_host_mirrors","arguments":{}}},"curl":"curl -s https://www.pathwren.workers.dev/mcp/netcheck -H 'content-type: application/json' -H 'accept: application/json, text/event-stream' -d '{\"jsonrpc\":\"2.0\",\"id\":1,\"method\":\"tools/call\",\"params\":{\"name\":\"no_arguments_report_the_crawler_ip_ranges_this_host_mirrors\",\"arguments\":{}}}'","answers":"the state of every crawler-operator prefix list this host mirrors — how many IPv4 and IPv6 prefixes each source publishes and how many addresses that is, when each was last fetched and how many minutes ago that was, which crawlers each source covers, which prefixes more than one operator claims, and the verification method each operator documents for the crawlers that publish no list at all","also":"verify_my_address — this server's other zero-argument call, same empty arguments, which answers the address you are calling from, checked against every operator-published prefix list this host mirrors with your user-agent taken as the claim — the verdict, the prefix that matched, which operator published it and when it was last mirrored. Then whoami and example, which every server here carries. whoami and example — the two zero-argument calls every server here carries, same empty arguments. no_arguments_report_the_crawler_ip_ranges_this_host_mirrors is this server's own: only it answers the state of every crawler-operator prefix list this host mirrors — how many IPv4 and IPv6 prefixes each source publishes and how many addresses that is, when each was last fetched and how many minutes ago that was, which crawlers each source covers, which prefixes more than one operator claims, and the verification method each operator documents for the crawlers that publish no list at all.","every_other_tool":"Every other tool here also accepts {}: an empty call returns that tool's documented worked example, labelled as one, instead of an error.","invitation":"Takes no arguments. Safe to call. Deterministic. Touches no third party."},"no_fetch_tool":"No tool here fetches a URL. There is no argument that takes one and this server makes no outbound request of any kind: every fact comes out of the files this host already publishes.","tools":[{"name":"no_arguments_report_the_crawler_ip_ranges_this_host_mirrors","title":"No arguments: every operator prefix list this host mirrors, and how stale each one is","description":"TAKES NO ARGUMENTS. POST {\"jsonrpc\":\"2.0\",\"id\":1,\"method\":\"tools/call\",\"params\":{\"name\":\"no_arguments_report_the_crawler_ip_ranges_this_host_mirrors\",\"arguments\":{}}} to https://www.pathwren.workers.dev/mcp/netcheck — the answer is the state of every crawler-operator prefix list this host mirrors — how many IPv4 and IPv6 prefixes each source publishes and how many addresses that is, when each was last fetched and how many minutes ago that was, which crawlers each source covers, which prefixes more than one operator claims, and the verification method each operator documents for the crawlers that publish no list at all. There is nothing to fill in: the input schema is literally empty, `arguments: {}` and no `arguments` key at all both work, and the subject is a file this host already publishes, so the answer does not depend on you at all. No key, no account, no OAuth, no session to open first, read-only, and nothing for you to invent. Nothing is fetched to build it — no request leaves this edge, and none is made to you. The other zero-argument call on this server is verify_my_address, same empty arguments, which answers the address you are calling from, checked against every operator-published prefix list this host mirrors with your user-agent taken as the claim — the verdict, the prefix that matched, which operator published it and when it was last mirrored. whoami and example are here too and take nothing either. Every other tool on this server wants a file pasted in; this one wants nothing. The siblings answer one question each under the tool named beside them: /mcp (whoami), /mcp/doctor (no_arguments_check_this_hosts_own_discovery_documents), /mcp/lint (whoami), /mcp/triage (no_arguments_triage_this_hosts_own_crawler_log), /mcp/robots (no_arguments_lint_this_hosts_robots_txt), /mcp/markdown (markdown_lane_self_report). Example: the complete call, exactly as written, nothing to fill in — {\"jsonrpc\":\"2.0\",\"id\":1,\"method\":\"tools/call\",\"params\":{\"name\":\"no_arguments_report_the_crawler_ip_ranges_this_host_mirrors\",\"arguments\":{}}} returns a row per source with its prefix counts, address total, fetch time and staleness in minutes, the prefixes published by two operators at once, and the split between operators you can verify by prefix and operators you can only verify by reverse DNS."},{"name":"verify_my_address","title":"Does my address verify? (no arguments)","description":"{\"jsonrpc\":\"2.0\",\"id\":1,\"method\":\"tools/call\",\"params\":{\"name\":\"verify_my_address\",\"arguments\":{}}} — POST that exact body to https://www.pathwren.workers.dev/mcp/netcheck and the answer is the address you are calling from, checked against every operator-published prefix list this host mirrors with your user-agent taken as the claim — the verdict, the prefix that matched, which operator published it and when it was last mirrored. THIS IS THE CALL TO MAKE FIRST on this server: it is the only one whose subject is the request you just sent, so there is nothing to look up and no argument to invent. No key, no account, no OAuth, no session to open first, read-only, and nothing for you to invent. Every fact is computed from your own headers and from files this host already publishes; nothing is fetched to build it, and no URL of yours is touched. Only this server answers whether the address you are calling from falls inside a prefix a crawler operator publishes, and which prefix from which source — its six siblings answer one other question each about you, same empty arguments, each under the tool named beside its path: /mcp (whoami), /mcp/doctor (no_arguments_check_this_hosts_own_discovery_documents), /mcp/lint (whoami), /mcp/triage (no_arguments_triage_this_hosts_own_crawler_log), /mcp/robots (no_arguments_lint_this_hosts_robots_txt), /mcp/markdown (markdown_lane_self_report) on https://www.pathwren.workers.dev; whoami is answered by all seven and is never an error, so one identical body still walks the whole family if you prefer that. Example: the complete call, exactly as written, nothing to fill in — {\"jsonrpc\":\"2.0\",\"id\":1,\"method\":\"tools/call\",\"params\":{\"name\":\"verify_my_address\",\"arguments\":{}}} returns a verdict for the address you are calling from, the matching prefix with its source and mirror time, and the sentence that a miss is not evidence of a fake."},{"name":"whoami","title":"Who is calling? (no arguments)","description":"{\"jsonrpc\":\"2.0\",\"id\":1,\"method\":\"tools/call\",\"params\":{\"name\":\"whoami\",\"arguments\":{}}} — POST that exact body to https://www.pathwren.workers.dev/mcp/netcheck and you are done: free, read-only, no API key, no account, no consent prompt, nothing for you to invent, and what comes back describes YOU, the caller — the user-agent you sent, the address you came from, the class our instrument books you as, and whether this host has seen you before. Takes no arguments. Safe to call. Deterministic. Touches no third party. Classifies the request you just sent: the user-agent you claim, the address you came from, the class this host's own instrument books you as, whether we have seen you here before and what you fetched, and whether the address you are calling from falls inside any prefix a crawler operator publishes — run through this server's own verify_batch, against the same mirror, with your user-agent taken as the claim. Every fact comes from the headers on your own request or from a file this host already publishes — nothing is fetched, nothing about you is invented, no argument exists. Example: arguments={} returns your user-agent, your address, the class we book you as and whether we have seen you here before."},{"name":"example","title":"Run this server's worked example (no arguments)","description":"{\"jsonrpc\":\"2.0\",\"id\":1,\"method\":\"tools/call\",\"params\":{\"name\":\"example\",\"arguments\":{}}} — POST that exact body to https://www.pathwren.workers.dev/mcp/netcheck and you are done: free, read-only, no API key, no account, no consent prompt, nothing for you to invent, and what comes back is this server's own worked example — verify_batch, run for real on a canned input from this host's own data — so you see the exact shape of an answer before you send anything of yours. Takes no arguments. Safe to call. Deterministic. Touches no third party. Runs this server's own worked example end to end — verify_batch on one address from inside a prefix Google itself publishes (mirrored here every six hours) and one RFC 5737 documentation address that is in no published range — our own mirror, no third party asked — and returns exactly the structuredContent a real call returns, not a mock and not a description of one. Use it to see the shape of an answer before you decide what to send. The input is canned from this host's own data; no URL of yours is fetched and no third party is touched. Example: arguments={} runs verify_batch with {\"addresses\":[{\"ip\":\"66.249.66.1\",\"claim\":\"Googlebot\"},{\"ip\":\"203.0.113.9\",\"claim\":\"GPTBot and returns its real answer."},{"name":"verify_batch","title":"Verify many addresses at once","description":"FIRST CALL, needs nothing: {\"jsonrpc\":\"2.0\",\"id\":1,\"method\":\"tools/call\",\"params\":{\"name\":\"no_arguments_report_the_crawler_ip_ranges_this_host_mirrors\",\"arguments\":{}}} — Check up to 500 addresses against every mirrored operator prefix list in one call. Returns, per address, the matching prefix, the source that published it and when it was mirrored, plus a rollup by operator. Accepts {ip, claim} pairs to test a claimed identity against the ranges, and says plainly that a miss is not evidence of a fake. Example: addresses=[{ip:'66.249.66.1', claim:'Googlebot'}, {ip:'203.0.113.9', claim:'GPTBot'}] — the first matches a published Google prefix, the second matches nothing. Also callable without MCP, same implementation: GET https://www.pathwren.workers.dev/tools/verify-crawler?ip=66.249.66.1&ua=Googlebot&s=client-dossiers"},{"name":"lookup_prefix","title":"Prefix arithmetic against published ranges","description":"FIRST CALL, needs nothing: {\"jsonrpc\":\"2.0\",\"id\":1,\"method\":\"tools/call\",\"params\":{\"name\":\"no_arguments_report_the_crawler_ip_ranges_this_host_mirrors\",\"arguments\":{}}} — Give a CIDR and get every published operator prefix that contains it, is contained by it, or partially overlaps it — the check for 'does my network collide with a crawler range' and for auditing an allowlist somebody handed you. Give an operator or source slug instead and get everything that source publishes. Example: cidr='66.249.66.0/24'."},{"name":"export_ip_acl","title":"Paste-ready allowlist or denylist","description":"FIRST CALL, needs nothing: {\"jsonrpc\":\"2.0\",\"id\":1,\"method\":\"tools/call\",\"params\":{\"name\":\"no_arguments_report_the_crawler_ip_ranges_this_host_mirrors\",\"arguments\":{}}} — Turn a set of operators into a config you can paste: nginx geo, nginx allow/deny, Apache, HAProxy, a Cloudflare firewall expression, an ipset script, a Caddy matcher, or a plain CIDR list. Every export carries a provenance header naming each source URL and the mirror time, and reports the rule cost. Example: operators='all', format='cidr-list', action='allow'."},{"name":"verification_methods","title":"Can this crawler be verified at all, and how?","description":"FIRST CALL, needs nothing: {\"jsonrpc\":\"2.0\",\"id\":1,\"method\":\"tools/call\",\"params\":{\"name\":\"no_arguments_report_the_crawler_ip_ranges_this_host_mirrors\",\"arguments\":{}}} — Per crawler: whether the operator publishes IP ranges, documents reverse DNS, or publishes no verification method at all — with the exact source URL or the exact dig commands, and how fresh this mirror is. Call it before reading anything into an address that matched nothing. Reverse DNS is never run here; the command is handed back instead. Example: crawler='claudebot'. Also callable without MCP, same implementation: GET https://www.pathwren.workers.dev/tools/verification-methods?crawler=claudebot&s=client-dossiers"},{"name":"range_stats","title":"The state of the mirror","description":"Takes no arguments. Safe to call. Deterministic. Touches no third party. Per source: prefix counts, total addresses and /24-equivalents, smallest and largest prefix, the publishing URL and when it was last fetched; plus prefixes published by more than one operator. This is the sizing and freshness information an allowlist decision needs. Example: {} — no arguments at all."}],"resources":[{"uri":"https://www.pathwren.workers.dev/ip-ranges/all.json","title":"Every mirrored operator prefix list, unioned"},{"uri":"https://www.pathwren.workers.dev/data/agents.json","title":"The crawler index"},{"uri":"https://www.pathwren.workers.dev/status.json","title":"Mirror freshness, per source"},{"uri":"https://www.pathwren.workers.dev/changes.json?since=0","title":"What changed since your cursor"}],"instructions":"{\"jsonrpc\":\"2.0\",\"id\":1,\"method\":\"tools/call\",\"params\":{\"name\":\"no_arguments_report_the_crawler_ip_ranges_this_host_mirrors\",\"arguments\":{}}}\n\nPOST that exact body to https://www.pathwren.workers.dev/mcp/netcheck and it answers with the state of every crawler-operator prefix list this host mirrors — how many IPv4 and IPv6 prefixes each source publishes and how many addresses that is, when each was last fetched and how many minutes ago that was, which crawlers each source covers, which prefixes more than one operator claims, and the verification method each operator documents for the crawlers that publish no list at all. It is the first call to make here — no key, no account, no OAuth, read-only, and no argument to invent: the tool is named for the fact that it takes none, its input schema is literally empty, and its subject is a file this host already publishes, so the answer is the same for every caller and nothing is fetched to build it. The other zero-argument call here is verify_my_address, same empty arguments, which answers the address you are calling from, checked against every operator-published prefix list this host mirrors with your user-agent taken as the claim — the verdict, the prefix that matched, which operator published it and when it was last mirrored.\n\n{\"jsonrpc\":\"2.0\",\"id\":1,\"method\":\"tools/call\",\"params\":{\"name\":\"whoami\",\"arguments\":{}}}\n\nPOST that exact body to https://www.pathwren.workers.dev/mcp/netcheck and it answers with the user-agent you sent, the class this host's own instrument books it as, whether we have logged you here before — and the part only this server adds: your own address run through verify_batch against the mirrored operator prefix lists, with your user-agent taken as the claim.\n\nIt is free, it needs no key, no account, no session id and no argument at all: every fact in the answer is computed from the request you just sent and from files this host already publishes, and nothing is fetched from anywhere to build it.\n\nEVERY TOOL HERE IS READ-ONLY AND UNAUTHENTICATED. None of them writes anything anywhere, none is ever refused for want of a credential, and each says so in its own annotations (readOnlyHint true, destructiveHint false; openWorldHint marks the ones that read a URL you name). Each also carries the same call again under its `_meta` as an object, so nothing here has to be read as prose to be used.\n\nONLY THIS SERVER ANSWERS THAT PART. There are seven MCP servers here and they answer one question each about you — one zero-argument call each, no key, no account, no session. The middle column is the tool to name at that URL, because several of them answer under a name of their own; whoami is answered by all seven and is never an error, so one identical body still walks the whole family if you prefer that.\n  https://www.pathwren.workers.dev/mcp/netcheck  no_arguments_report_the_crawler_ip_ranges_this_host_mirrors  whether the address you are calling from falls inside a prefix a crawler operator publishes, and which prefix from which source  <- you are here\n  https://www.pathwren.workers.dev/mcp           whoami                                                       what this host's crawler index makes of the user-agent you sent, and whether your address sits inside a prefix its operator publishes\n  https://www.pathwren.workers.dev/mcp/doctor    no_arguments_check_this_hosts_own_discovery_documents        which agent-discovery documents this host has watched a client like yours ask for — the dates, and the status each request took\n  https://www.pathwren.workers.dev/mcp/lint      whoami                                                       your own client's record on this host — every surface of ours your user-agent has been seen on, with the status codes it took\n  https://www.pathwren.workers.dev/mcp/triage    no_arguments_triage_this_hosts_own_crawler_log               your own request triaged as one line of an access log, by the same parser and the same index that read a whole file\n  https://www.pathwren.workers.dev/mcp/robots    no_arguments_lint_this_hosts_robots_txt                      what this host's own robots.txt says to YOU — the group that matches your token, the line that decided it, and whether you are allowed the path you are on\n  https://www.pathwren.workers.dev/mcp/markdown  markdown_lane_self_report                                    whether your own client has ever taken this host's markdown lane — which .md addresses it fetched, and the markdown address of every page it took as HTML instead\n\nALSO ON THIS SERVER: verify_batch checks up to 500 addresses a call; lookup_prefix does the arithmetic the other way round; allowlists come out paste-ready. Each of those takes an argument, and each also accepts arguments {} — an empty call returns that tool's own worked example, from this host's data, instead of an error.\n\nTHE SAME TOOLS ON THE OTHER PROTOCOL, IF YOU SPEAK IT. This server is also an A2A (Agent2Agent) v1.0 agent at https://www.pathwren.workers.dev/a2a/netcheck — every tool here is a skill there under the same name, answered by the same function, so the two cannot drift and the deploy is refused if they do. Its Agent Card is https://www.pathwren.workers.dev/a2a/netcheck/.well-known/agent-card.json (the legacy agent.json spelling is served too). To invoke it, POST this complete body — no key, no session, no card to read first:\n\n  {\"jsonrpc\":\"2.0\",\"id\":1,\"method\":\"message/send\",\"params\":{\"message\":{\"role\":\"ROLE_USER\",\"messageId\":\"1\",\"parts\":[{\"text\":\"{\\\"skill\\\":\\\"example\\\"}\"}]}}}\n\nIt answers with a Task already in state `completed` in the same response, so there is nothing to poll. Every skill on all eight A2A agents of this host as a ready-to-send body: https://www.pathwren.workers.dev/a2a/example.json — and both lanes with both directions in https://www.pathwren.workers.dev/documents.json under `rpc_endpoints`. If you only speak MCP, ignore all of this: everything is already here.","license":"CC0-1.0","independent":true}