Dechonet MCP

Reverse DNS (PTR) Lookup

reverse_dns

Read-onlyIdempotent

Resolve PTR records for any IPv4 or IPv6 address and verify forward-confirmed reverse DNS. Use to validate mail-server rDNS or identify the hosting provider from PTR naming patterns.

Instructions

Resolve the PTR (reverse DNS) record for an IPv4 or IPv6 address and verify forward-confirmed reverse DNS (FCrDNS) by checking that the PTR hostname resolves back to the same IP. Infers the hosting provider from PTR naming patterns. Use this to validate mail-server rDNS or identify a single IP's host. Use asn_lookup instead for network/BGP ownership of the IP. Read-only; requires no API key; rate-limited. Returns the PTR hostname, FCrDNS pass/fail, and a provider guess.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`ip`	Yes	IP address to reverse-resolve, IPv4 or IPv6 (e.g., '8.8.8.8' or '2001:4860:4860::8888'). Must be an IP, not a hostname.

Output Schema

TableJSON Schema

Name	Required	Description
`kpis`	No	Key metrics as label/value pairs
`grade`	No	Letter grade (A+ to F) when the tool grades the target
`score`	No	0-100 score when the tool scores the target
`issues`	No	Detected problems, severity-rated
`status`	Yes	Overall verdict, e.g. 'good' \| 'warning' \| 'bad' \| 'info' \| 'unknown'
`actions`	No	Recommended next actions, most important first
`summary`	No	One-paragraph interpretation of the result
`reportUrl`	Yes	Human-facing interactive report for this exact lookup on dechonet.com

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedv1.1.0Sep 8, 2026

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "additionalProperties": false,
+  "properties": {
+    "actions": {
+      "description": "Recommended next actions, most important first",
+      "items": {
+        "type": "string"
+      },
+      "type": "array"
+    },
+    "grade": {
+      "description": "Letter grade (A+ to F) when the tool grades the target",
+      "type": "string"
+    },
+    "issues": {
+      "description": "Detected problems, severity-rated",
+      "items": {
+        "additionalProperties": false,
+        "properties": {
+          "key": {
+            "type": "string"
+          },
+          "severity": {
+            "type": "string"
+          }
+        },
+        "required": [
+          "severity",
+          "key"
+        ],
+        "type": "object"
+      },
+      "type": "array"
+    },
+    "kpis": {
+      "description": "Key metrics as label/value pairs",
+      "items": {
+        "additionalProperties": false,
+        "properties": {
+          "label": {
+            "type": "string"
+          },
+          "value": {
+            "type": "string"
+          }
+        },
+        "required": [
+          "label",
+          "value"
+        ],
+        "type": "object"
+      },
+      "type": "array"
+    },
+    "reportUrl": {
+      "description": "Human-facing interactive report for this exact lookup on dechonet.com",
+      "type": "string"
+    },
+    "score": {
+      "description": "0-100 score when the tool scores the target",
+      "type": "number"
+    },
+    "status": {
+      "description": "Overall verdict, e.g. 'good' | 'warning' | 'bad' | 'info' | 'unknown'",
+      "type": "string"
+    },
+    "summary": {
+      "description": "One-paragraph interpretation of the result",
+      "type": "string"
+    }
+  },
+  "required": [
+    "status",
+    "reportUrl"
+  ],
+  "type": "object"
+}

Changed1 schema field changedv1.0.3Jun 17, 2026

changedInput schema / properties / ip / description

Previous value: -"IP address to look up (IPv4 or IPv6)"New value: +"IP address to reverse-resolve, IPv4 or IPv6 (e.g., '8.8.8.8' or '2001:4860:4860::8888'). Must be an IP, not a hostname."

First observedv0.1.0Jun 17, 2026

TDQS

A4.7/5.0

Behavior5/5

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

Discloses behavior beyond annotations: FCrDNS verification, provider inference, return values, and rate limit. Matches readOnlyHint and idempotentHint.

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?

Concise, front-loaded with main action, then usage guidance and alternative. No fluff.

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

Completeness5/5

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

Complete for single-param tool: covers input, output, use cases, alternatives, and constraints. Nothing missing.

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

Parameters3/5

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

Schema already documents ip with full description (IPv4/IPv6, examples, must be IP not hostname). Tool description adds no new parameter details beyond restating it is an IP address.

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?

Clearly states it resolves PTR records, verifies FCrDNS, and infers hosting provider, and distinguishes from asn_lookup.

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

Usage Guidelines5/5

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

Explicitly tells when to use (validate mail-server rDNS, identify single IP's host) and when to use alternative (asn_lookup for network/BGP ownership), plus notes read-only, no API key, rate-limited.

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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