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contrastapi

contrastapi

by UPinar
OverviewSchemaSourceRelated ServersDiscussionsAdmin
Python
Hybrid

ASN Lookup

asn_lookup
Read-onlyIdempotent

Determine network ownership by looking up the ASN for any domain or IP. Get AS number, organization, and IPv4/IPv6 prefixes to identify the operator and IP range ownership.

Instructions

Look up Autonomous System Number (ASN) for a domain or IP: AS number, organization, IPv4/IPv6 prefixes. Use to identify network operator and IP range ownership. Default returns first 50 prefixes per family — set include_full_prefixes=True for full list. Free: 30/hr, Pro: 500/hr. Returns {asn, asn_name, ipv4_prefixes, ipv6_prefixes, ipv4_count, ipv6_count}.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "target": "<target>"
    },
    "name": "asn_lookup"
  }
}

Input Schema

NameRequiredDescriptionDefault
targetYesDomain or IP address to look up ASN for (e.g. 'cloudflare.com', '8.8.8.8')
include_full_prefixesNoReturn the full announced-prefixes list (default: False, returns first 50). ipv4_count and ipv6_count are always honest pre-truncation totals. Set True for network mapping or BGP route audits — Cloudflare AS13335 announces 2500+ prefixes.

Output Schema

NameRequiredDescriptionDefault
resultYes

Schema Changelog

Changes observed during successful MCP inspections.

  1. Changed1 schema field changedv1.34.4
    • changedOutput schema / $defs / PivotHint / properties / tool / enum
      Previous value: -[
-  "cve_lookup",
-  "cve_search",
-  "cve_leading",
-  "bulk_cve_lookup",
-  "calculate_risk_score",
-  "get_cvss_details",
-  "exploit_lookup",
-  "kev_detail",
-  "cwe_lookup",
-  "subdomain_enum",
-  "ssl_check",
-  "tech_fingerprint",
-  "asn_lookup",
-  "ip_lookup",
-  "ioc_lookup",
-  "bulk_ioc_lookup",
-  "hash_lookup",
-  "threat_intel",
-  "threat_report",
-  "audit_domain",
-  "domain_report",
-  "dns_lookup",
-  "whois_lookup",
-  "wayback_lookup",
-  "scan_headers",
-  "check_headers",
-  "check_secrets",
-  "check_injection",
-  "check_dependencies",
-  "email_mx",
-  "email_security_posture",
-  "email_disposable",
-  "email_verify",
-  "robots_txt",
-  "redirect_chain",
-  "brand_assets",
-  "seo_audit",
-  "phone_lookup",
-  "username_lookup",
-  "password_check",
-  "phishing_check",
-  "atlas_technique_lookup",
-  "atlas_technique_search",
-  "bulk_atlas_technique_lookup",
-  "atlas_case_study_lookup",
-  "atlas_case_study_search",
-  "d3fend_defense_lookup",
-  "d3fend_defense_search",
-  "d3fend_defense_for_attack",
-  "d3fend_attack_coverage",
-  "sigma_rule_lookup",
-  "bulk_sigma_rule_lookup",
-  "tech_stack_cve_audit",
-  "contrast_scan"
-]New value: +[
+  "cve_lookup",
+  "cve_search",
+  "cve_leading",
+  "bulk_cve_lookup",
+  "calculate_risk_score",
+  "get_cvss_details",
+  "exploit_lookup",
+  "kev_detail",
+  "cwe_lookup",
+  "subdomain_enum",
+  "ssl_check",
+  "tech_fingerprint",
+  "asn_lookup",
+  "ip_lookup",
+  "ioc_lookup",
+  "bulk_ioc_lookup",
+  "hash_lookup",
+  "threat_intel",
+  "threat_report",
+  "audit_domain",
+  "domain_report",
+  "dns_lookup",
+  "whois_lookup",
+  "wayback_lookup",
+  "scan_headers",
+  "check_headers",
+  "check_secrets",
+  "check_injection",
+  "check_dependencies",
+  "email_mx",
+  "email_security_posture",
+  "email_disposable",
+  "email_verify",
+  "robots_txt",
+  "redirect_chain",
+  "brand_assets",
+  "seo_audit",
+  "geo_audit",
+  "phone_lookup",
+  "username_lookup",
+  "password_check",
+  "phishing_check",
+  "atlas_technique_lookup",
+  "atlas_technique_search",
+  "bulk_atlas_technique_lookup",
+  "atlas_case_study_lookup",
+  "atlas_case_study_search",
+  "d3fend_defense_lookup",
+  "d3fend_defense_search",
+  "d3fend_defense_for_attack",
+  "d3fend_attack_coverage",
+  "sigma_rule_lookup",
+  "bulk_sigma_rule_lookup",
+  "tech_stack_cve_audit",
+  "contrast_scan"
+]
  2. Changed1 schema field changedv1.33.23
    • changedOutput schema / $defs / PivotHint / properties / tool / enum
      Previous value: -[
-  "cve_lookup",
-  "cve_search",
-  "cve_leading",
-  "bulk_cve_lookup",
-  "calculate_risk_score",
-  "get_cvss_details",
-  "exploit_lookup",
-  "kev_detail",
-  "cwe_lookup",
-  "subdomain_enum",
-  "ssl_check",
-  "tech_fingerprint",
-  "asn_lookup",
-  "ip_lookup",
-  "ioc_lookup",
-  "bulk_ioc_lookup",
-  "hash_lookup",
-  "threat_intel",
-  "threat_report",
-  "audit_domain",
-  "domain_report",
-  "dns_lookup",
-  "whois_lookup",
-  "wayback_lookup",
-  "scan_headers",
-  "check_headers",
-  "check_secrets",
-  "check_injection",
-  "check_dependencies",
-  "email_mx",
-  "email_security_posture",
-  "email_disposable",
-  "email_verify",
-  "robots_txt",
-  "redirect_chain",
-  "brand_assets",
-  "seo_audit",
-  "phone_lookup",
-  "username_lookup",
-  "password_check",
-  "phishing_check",
-  "atlas_technique_lookup",
-  "atlas_technique_search",
-  "bulk_atlas_technique_lookup",
-  "atlas_case_study_lookup",
-  "atlas_case_study_search",
-  "d3fend_defense_lookup",
-  "d3fend_defense_search",
-  "d3fend_defense_for_attack",
-  "d3fend_attack_coverage",
-  "sigma_rule_lookup",
-  "bulk_sigma_rule_lookup",
-  "tech_stack_cve_audit"
-]New value: +[
+  "cve_lookup",
+  "cve_search",
+  "cve_leading",
+  "bulk_cve_lookup",
+  "calculate_risk_score",
+  "get_cvss_details",
+  "exploit_lookup",
+  "kev_detail",
+  "cwe_lookup",
+  "subdomain_enum",
+  "ssl_check",
+  "tech_fingerprint",
+  "asn_lookup",
+  "ip_lookup",
+  "ioc_lookup",
+  "bulk_ioc_lookup",
+  "hash_lookup",
+  "threat_intel",
+  "threat_report",
+  "audit_domain",
+  "domain_report",
+  "dns_lookup",
+  "whois_lookup",
+  "wayback_lookup",
+  "scan_headers",
+  "check_headers",
+  "check_secrets",
+  "check_injection",
+  "check_dependencies",
+  "email_mx",
+  "email_security_posture",
+  "email_disposable",
+  "email_verify",
+  "robots_txt",
+  "redirect_chain",
+  "brand_assets",
+  "seo_audit",
+  "phone_lookup",
+  "username_lookup",
+  "password_check",
+  "phishing_check",
+  "atlas_technique_lookup",
+  "atlas_technique_search",
+  "bulk_atlas_technique_lookup",
+  "atlas_case_study_lookup",
+  "atlas_case_study_search",
+  "d3fend_defense_lookup",
+  "d3fend_defense_search",
+  "d3fend_defense_for_attack",
+  "d3fend_attack_coverage",
+  "sigma_rule_lookup",
+  "bulk_sigma_rule_lookup",
+  "tech_stack_cve_audit",
+  "contrast_scan"
+]
  3. Addedv1.33.21
  4. Removedv1.33.14
  5. Addedv1.33.1
  6. Removedv1.33.0
  7. Addedv1.32.0
  8. Removedv1.30.2
  9. Changed1 schema field changedv1.29.1
    • changedOutput schema / $defs / PivotHint / properties / tool / enum
      Previous value: -[
-  "cve_lookup",
-  "cve_search",
-  "cve_leading",
-  "bulk_cve_lookup",
-  "exploit_lookup",
-  "kev_detail",
-  "cwe_lookup",
-  "subdomain_enum",
-  "ssl_check",
-  "tech_fingerprint",
-  "asn_lookup",
-  "ip_lookup",
-  "ioc_lookup",
-  "bulk_ioc_lookup",
-  "hash_lookup",
-  "threat_intel",
-  "threat_report",
-  "audit_domain",
-  "domain_report",
-  "dns_lookup",
-  "whois_lookup",
-  "wayback_lookup",
-  "scan_headers",
-  "check_headers",
-  "check_secrets",
-  "check_injection",
-  "check_dependencies",
-  "email_mx",
-  "email_disposable",
-  "email_verify",
-  "robots_txt",
-  "redirect_chain",
-  "brand_assets",
-  "seo_audit",
-  "phone_lookup",
-  "username_lookup",
-  "password_check",
-  "phishing_check",
-  "atlas_technique_lookup",
-  "atlas_technique_search",
-  "bulk_atlas_technique_lookup",
-  "atlas_case_study_lookup",
-  "atlas_case_study_search",
-  "d3fend_defense_lookup",
-  "d3fend_defense_search",
-  "d3fend_defense_for_attack",
-  "d3fend_attack_coverage"
-]New value: +[
+  "cve_lookup",
+  "cve_search",
+  "cve_leading",
+  "bulk_cve_lookup",
+  "calculate_risk_score",
+  "get_cvss_details",
+  "exploit_lookup",
+  "kev_detail",
+  "cwe_lookup",
+  "subdomain_enum",
+  "ssl_check",
+  "tech_fingerprint",
+  "asn_lookup",
+  "ip_lookup",
+  "ioc_lookup",
+  "bulk_ioc_lookup",
+  "hash_lookup",
+  "threat_intel",
+  "threat_report",
+  "audit_domain",
+  "domain_report",
+  "dns_lookup",
+  "whois_lookup",
+  "wayback_lookup",
+  "scan_headers",
+  "check_headers",
+  "check_secrets",
+  "check_injection",
+  "check_dependencies",
+  "email_mx",
+  "email_disposable",
+  "email_verify",
+  "robots_txt",
+  "redirect_chain",
+  "brand_assets",
+  "seo_audit",
+  "phone_lookup",
+  "username_lookup",
+  "password_check",
+  "phishing_check",
+  "atlas_technique_lookup",
+  "atlas_technique_search",
+  "bulk_atlas_technique_lookup",
+  "atlas_case_study_lookup",
+  "atlas_case_study_search",
+  "d3fend_defense_lookup",
+  "d3fend_defense_search",
+  "d3fend_defense_for_attack",
+  "d3fend_attack_coverage"
+]
  10. Changed1 schema field changedv1.25.0
    • changedOutput schema / $defs / PivotHint / properties / tool / enum
      Previous value: -[
-  "cve_lookup",
-  "cve_search",
-  "cve_leading",
-  "bulk_cve_lookup",
-  "exploit_lookup",
-  "kev_detail",
-  "cwe_lookup",
-  "subdomain_enum",
-  "ssl_check",
-  "tech_fingerprint",
-  "asn_lookup",
-  "ip_lookup",
-  "ioc_lookup",
-  "bulk_ioc_lookup",
-  "hash_lookup",
-  "threat_intel",
-  "threat_report",
-  "audit_domain",
-  "domain_report",
-  "dns_lookup",
-  "whois_lookup",
-  "wayback_lookup",
-  "scan_headers",
-  "check_headers",
-  "check_secrets",
-  "check_injection",
-  "check_dependencies",
-  "email_mx",
-  "email_disposable",
-  "phone_lookup",
-  "username_lookup",
-  "password_check",
-  "phishing_check",
-  "atlas_technique_lookup",
-  "atlas_technique_search",
-  "bulk_atlas_technique_lookup",
-  "atlas_case_study_lookup",
-  "atlas_case_study_search",
-  "d3fend_defense_lookup",
-  "d3fend_defense_search",
-  "d3fend_defense_for_attack",
-  "d3fend_attack_coverage"
-]New value: +[
+  "cve_lookup",
+  "cve_search",
+  "cve_leading",
+  "bulk_cve_lookup",
+  "exploit_lookup",
+  "kev_detail",
+  "cwe_lookup",
+  "subdomain_enum",
+  "ssl_check",
+  "tech_fingerprint",
+  "asn_lookup",
+  "ip_lookup",
+  "ioc_lookup",
+  "bulk_ioc_lookup",
+  "hash_lookup",
+  "threat_intel",
+  "threat_report",
+  "audit_domain",
+  "domain_report",
+  "dns_lookup",
+  "whois_lookup",
+  "wayback_lookup",
+  "scan_headers",
+  "check_headers",
+  "check_secrets",
+  "check_injection",
+  "check_dependencies",
+  "email_mx",
+  "email_disposable",
+  "email_verify",
+  "robots_txt",
+  "redirect_chain",
+  "brand_assets",
+  "seo_audit",
+  "phone_lookup",
+  "username_lookup",
+  "password_check",
+  "phishing_check",
+  "atlas_technique_lookup",
+  "atlas_technique_search",
+  "bulk_atlas_technique_lookup",
+  "atlas_case_study_lookup",
+  "atlas_case_study_search",
+  "d3fend_defense_lookup",
+  "d3fend_defense_search",
+  "d3fend_defense_for_attack",
+  "d3fend_attack_coverage"
+]
  11. Addedv1.23.0
  12. Removedv1.0.18
  13. Changed1 schema field changedv1.0.5
    • addedInput schema / properties / include_full_prefixes
      Added value: +{
+  "default": false,
+  "description": "Return the full announced-prefixes list (default: False, returns first 50). ipv4_count and ipv6_count are always honest pre-truncation totals. Set True for network mapping or BGP route audits — Cloudflare AS13335 announces 2500+ prefixes.",
+  "title": "Include Full Prefixes",
+  "type": "boolean"
+}
  14. Addedv1.0.1

TDQS

A4.6/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Beyond annotations (readOnly, idempotent, non-destructive), the description discloses default truncation (first 50 prefixes), the effect of setting include_full_prefixes=True, and that ipv4_count and ipv6_count are honest pre-truncation totals. It also includes rate limits. No contradictions with annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is succinct (three sentences) with the main purpose front-loaded. Every sentence adds useful information, and there is no redundant or extraneous content.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The description covers inputs, outputs (with a clear return format hint), and default behavior. Given the presence of an output schema, the description is sufficiently complete. It does not cover error cases, but the tool is simple enough.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Both parameters have schema descriptions (100% coverage). The description adds value by explaining the default behavior for include_full_prefixes and providing a concrete example (Cloudflare AS13335) to illustrate when to use it.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool looks up ASN for a domain or IP, specifying what it returns (AS number, organization, IPv4/IPv6 prefixes). It distinguishes from sibling lookup tools by focusing on network operator identification.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides context on when to use the tool (e.g., for network mapping or BGP route audits) and mentions default vs. full prefix behavior. It does not explicitly mention when not to use it or list alternatives, but the context is clear enough.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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