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network_cidr_calculator

Read-onlyIdempotent

Parse an IPv4 CIDR block or IP plus mask to get network/broadcast addresses, host ranges, subnet masks, and flags for private, loopback, multicast, link-local.

Instructions

CIDR Notation Calculator. Parse one IPv4 CIDR block (e.g. 192.168.1.0/24) or an IP plus dotted-decimal mask and return network/broadcast addresses, first/last host, total and usable host counts, subnet and wildcard masks, dotted-binary of each, network class, RFC 1918 private flag plus loopback/multicast/link-local flags, a sample child-subnet split, and a plain-text size/use summary. Use network_subnet_calculator for the same math with explicit IP-plus-mask form fields, or network_ip_range_calculator to enumerate every address in a block. Pure offline IPv4 math: read-only, non-destructive, contacts no DNS or network service, and is rate-limited (30 requests/minute for anonymous callers).

Input Schema

TableJSON Schema

Name	Required	Description	Default
`input`	Yes	One IPv4 network in CIDR form like 192.168.1.0/24 (prefix 0-32), or an IP and contiguous dotted-decimal mask separated by a space like 192.168.1.0 255.255.255.0. A bare IP with no slash or mask is treated as /32. Each octet must be 0-255.
`worker_id`	No	Optional registered healthy worker peer ID. Omit to use the default master-server behavior.

Output Schema

TableJSON Schema

Name	Required	Description
`success`	No	Always true on a 200; error responses use HTTP 400.
`input`	No	The submitted network string, trimmed and echoed back.
`calculations`	No	Computed network details for the parsed block.

Schema Changelog

Changes observed during successful MCP inspections.

Changed4 schema fields changedv0.5.1Jun 3, 2026

changedInput schema / additionalProperties
```
Previous value: -trueNew value: +false
```

addedInput schema / properties / input

Added value: +{
+  "description": "One IPv4 network in CIDR form like 192.168.1.0/24 (prefix 0-32), or an IP and contiguous dotted-decimal mask separated by a space like 192.168.1.0 255.255.255.0. A bare IP with no slash or mask is treated as /32. Each octet must be 0-255.",
+  "maxLength": 35,
+  "minLength": 7,
+  "type": "string"
+}

addedInput schema / required
```
Added value: +[
+  "input"
+]
```

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "properties": {
+    "calculations": {
+      "description": "Computed network details for the parsed block.",
+      "properties": {
+        "binary": {
+          "description": "Dotted-binary forms of the key masks and addresses.",
+          "properties": {
+            "network_address": {
+              "description": "Network address in dotted binary.",
+              "type": "string"
+            },
+            "subnet_mask": {
+              "description": "Subnet mask in dotted binary.",
+              "type": "string"
+            },
+            "wildcard_mask": {
+              "description": "Wildcard mask in dotted binary.",
+              "type": "string"
+            }
+          },
+          "type": "object"
+        },
+        "broadcast_address": {
+          "description": "Broadcast address of the block.",
+          "type": "string"
+        },
+        "cidr_notation": {
+          "description": "Normalised network/prefix, e.g. 192.168.1.0/24.",
+          "type": "string"
+        },
+        "first_host": {
+          "description": "First usable host (network + 1), or N/A when none.",
+          "type": "string"
+        },
+        "input_ip": {
+          "description": "The IPv4 address parsed from the input (before masking).",
+          "type": "string"
+        },
+        "is_link_local": {
+          "description": "Whether the network is in 169.254.0.0/16.",
+          "type": "boolean"
+        },
+        "is_loopback": {
+          "description": "Whether the network is in 127.0.0.0/8.",
+          "type": "boolean"
+        },
+        "is_multicast": {
+          "description": "Whether the network is in 224.0.0.0/4.",
+          "type": "boolean"
+        },
+        "is_private": {
+          "description": "Whether the network is RFC 1918 private space.",
+          "type": "boolean"
+        },
+        "last_host": {
+          "description": "Last usable host (broadcast - 1), or N/A when none.",
+          "type": "string"
+        },
+        "network_address": {
+          "description": "Network (subnet) address.",
+          "type": "string"
+        },
+        "network_class": {
+          "description": "Classful range label for the network (A through E).",
+          "type": "string"
+        },
+        "prefix_length": {
+          "description": "CIDR prefix length, 0-32.",
+          "type": "integer"
+        },
+        "subnet_mask": {
+          "description": "Dotted-decimal subnet mask for the prefix.",
+          "type": "string"
+        },
+        "subnets": {
+          "description": "Sample equal-size child subnets (one prefix longer); empty for very large or very small blocks.",
+          "items": {
+            "properties": {
+              "broadcast": {
+                "description": "Child broadcast address.",
+                "type": "string"
+              },
+              "cidr": {
+                "description": "Child subnet in network/prefix form.",
+                "type": "string"
+              },
+              "hosts": {
+                "description": "Usable hosts in the child subnet.",
+                "type": "integer"
+              },
+              "network": {
+                "description": "Child network address.",
+                "type": "string"
+              }
+            },
+            "type": "object"
+          },
+          "type": "array"
+        },
+        "summary": {
+          "description": "Human-readable sizing notes.",
+          "properties": {
+            "common_use": {
+              "description": "Typical real-world use of this prefix.",
+              "type": "string"
+            },
+            "network_size": {
+              "description": "Network size category description.",
+              "type": "string"
+            },
+            "subnet_type": {
+              "description": "Subnet-type label for the prefix.",
+              "type": "string"
+            }
+          },
+          "type": "object"
+        },
+        "total_addresses": {
+          "description": "Total addresses in the block (two to the power of the host bits).",
+          "type": "integer"
+        },
+        "usable_hosts": {
+          "description": "Usable hosts (total minus 2, minimum 0).",
+          "type": "integer"
+        },
+        "wildcard_mask": {
+          "description": "Inverse (wildcard) mask, e.g. 0.0.0.255.",
+          "type": "string"
+        }
+      },
+      "type": "object"
+    },
+    "input": {
+      "description": "The submitted network string, trimmed and echoed back.",
+      "type": "string"
+    },
+    "success": {
+      "description": "Always true on a 200; error responses use HTTP 400.",
+      "type": "boolean"
+    }
+  },
+  "type": "object"
+}

First observedv0.1.0May 31, 2026

TDQS

A4.9/5.0

Behavior5/5

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

Annotations already indicate readOnlyHint, destructiveHint, idempotentHint. The description adds context: pure offline IPv4 math, no DNS/network contact, rate-limited (30 req/min). This exceeds annotation information without contradiction.

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

Conciseness4/5

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

The description is a single paragraph that packs a lot of information. While comprehensive, it could be more structured (e.g., bullet points) for quick scanning. However, every sentence adds value, and it is overall concise.

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?

Given the output schema exists (though not provided here), the description lists all key outputs: network/broadcast, first/last host, counts, masks, binary, class, RFC 1918 flag, sample subnet split, and summary. For a 2-parameter tool, this is fully complete.

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

Parameters5/5

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

Schema coverage is 100% with descriptions for both parameters. The description adds examples (e.g., '192.168.1.0/24', '192.168.1.0 255.255.255.0') and clarifies behavior for bare IPs (treated as /32), enriching understanding beyond the schema.

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 parses IPv4 CIDR notation or IP+mask and returns a comprehensive set of network details. It explicitly distinguishes itself from sibling tools like network_subnet_calculator and network_ip_range_calculator.

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?

The description provides explicit when-to-use and when-not-to-use guidance, mentioning alternatives for different input forms (network_subnet_calculator for explicit IP-plus-mask, network_ip_range_calculator for enumeration). It also notes offline and rate-limited behavior.

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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