Technitium MCP Secure

dns_list_cache

List cached DNS zones hierarchically. Omit domain to see top-level zones, or specify a domain like 'com' to drill into its cached subdomains.

Instructions

List zones in the DNS cache. Returns a hierarchical tree — call with no domain to see top-level zones, then pass a domain (e.g. 'com') to drill into cached subdomains.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`domain`	No	Optional parent domain to list children of (e.g. 'com' to see cached .com domains). Omit to see top-level zones.

Implementation Reference

src/tools/cache.ts:60-65 (handler)

The handler function for dns_list_cache. Accepts an optional domain argument, validates it, calls the /api/cache/list endpoint, and returns the result as formatted JSON.

handler: async (args) => {
  const params: Record<string, string> = {};
  if (args.domain) params.domain = validateDomain(args.domain as string);
  const data = await client.callOrThrow("/api/cache/list", params);
  return JSON.stringify(data, null, 2);
},

src/tools/cache.ts:44-58 (schema)

The schema/definition for dns_list_cache. Declares the tool name, description, and inputSchema with an optional 'domain' string property.

definition: {
  name: "dns_list_cache",
  description:
    "List zones in the DNS cache. Returns a hierarchical tree — call with no domain to see top-level zones, then pass a domain (e.g. 'com') to drill into cached subdomains.",
  inputSchema: {
    type: "object",
    properties: {
      domain: {
        type: "string",
        description:
          "Optional parent domain to list children of (e.g. 'com' to see cached .com domains). Omit to see top-level zones.",
      },
    },
  },
},

src/tools/index.ts:8-8 (registration)
Import of cacheTools (which includes dns_list_cache) into the tool index.
```
import { cacheTools } from "./cache.js";
```
src/tools/index.ts:21-21 (registration)
Registration of cacheTools (including dns_list_cache) into the getAllTools array.
```
...cacheTools(client),
```

src/validate.ts:5-17 (helper)

The validateDomain helper used by the handler to validate and normalize the domain argument before passing it to the API.

export function validateDomain(domain: string): string {
  if (!domain || typeof domain !== "string") {
    throw new Error("Domain name is required");
  }
  const trimmed = domain.trim().toLowerCase();
  if (trimmed.length > 253) {
    throw new Error("Domain name exceeds maximum length of 253 characters");
  }
  if (!DOMAIN_RE.test(trimmed)) {
    throw new Error("Invalid domain name format");
  }
  return trimmed;
}

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedv1.2.0May 4, 2026

addedInput schema / properties / domain

Added value: +{
+  "description": "Optional parent domain to list children of (e.g. 'com' to see cached .com domains). Omit to see top-level zones.",
+  "type": "string"
+}

First observedv1.1.0Feb 12, 2026

TDQS

A4/5.0

Behavior4/5

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

With no annotations, the description carries the burden of behavioral disclosure. It explains the hierarchical tree return format and the two-step drill-down behavior, which goes beyond the tool name and schema. It does not mention side effects, but as a 'list' operation, this is likely safe.

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 two sentences, front-loaded with the core purpose, and every sentence adds value. No filler or redundancy.

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?

For a read-only list tool with one optional parameter and no output schema, the description sufficiently covers purpose, usage, and the general return shape (hierarchical tree). The drill-down pattern is clearly explained, making the tool usable without further clarification.

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?

The sole parameter 'domain' is fully described in the schema (100% coverage), including its optionality and meaning. The description's mention of calling with no domain and then passing a domain reiterates the schema rather than adding new semantic value.

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 identifies the tool's action and resource: 'List zones in the DNS cache'. It also adds a distinctive behavior (hierarchical tree) that sets it apart from sibling list tools like dns_list_zones or dns_list_records.

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

Usage Guidelines3/5

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

The description provides explicit drill-down instructions ('call with no domain to see top-level zones, then pass a domain'), which is useful. However, it does not mention when to use this tool over alternatives such as dns_list_zones or dns_list_records, or when not to use it.

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