nginx-certbot-mcp

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list_sites

Read-only

Lists nginx server blocks from sites-enabled, showing domain, upstream, and SSL configuration status. Read-only tool parses config files directly to provide an overview of active sites.

Instructions

List every nginx server block currently in sites-enabled, with domain, upstream, and whether SSL looks configured. Read-only - parses config files directly, does not shell out to nginx. Use get_site_config for one domain's full raw config.

Input Schema

TableJSON Schema

Name	Required	Description	Default
No arguments

Output Schema

TableJSON Schema

Name	Required	Description	Default
`sites`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedv0.1.1Sep 15, 2026

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "additionalProperties": false,
+  "properties": {
+    "sites": {
+      "items": {
+        "additionalProperties": false,
+        "properties": {
+          "config_path": {
+            "description": "Absolute path to the enabled config file",
+            "type": "string"
+          },
+          "domain": {
+            "description": "server_name parsed from the config, or the filename if not found",
+            "type": "string"
+          },
+          "ssl_enabled": {
+            "description": "True if the config listens on 443 ssl or sets ssl_certificate",
+            "type": "boolean"
+          },
+          "upstream": {
+            "description": "proxy_pass target, or null if none was found",
+            "type": [
+              "string",
+              "null"
+            ]
+          }
+        },
+        "required": [
+          "domain",
+          "config_path",
+          "upstream",
+          "ssl_enabled"
+        ],
+        "type": "object"
+      },
+      "type": "array"
+    }
+  },
+  "required": [
+    "sites"
+  ],
+  "type": "object"
+}

First observedv0.1.0Sep 15, 2026

TDQS

A4.7/5.0

Behavior4/5

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

Annotations already declare readOnlyHint=true, and the description adds useful behavioral detail beyond that: it parses config files directly and does not shell out to nginx. This clarifies how the read-only operation is performed and implies a lightweight, direct inspection.

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 function and scope, then the read-only behavior, then the sibling alternative. Every sentence adds distinct value with no redundancy.

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?

For a parameterless read-only list tool with an output schema and strong annotations, the description fully covers purpose, scope, behavior, and the relevant sibling tool. Nothing an agent needs to invoke it correctly is missing.

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?

The tool has zero parameters, so the baseline is 4. The description adds no parameter syntax, but that is unnecessary here; the empty schema and zero-parameter context fully describe invocation requirements.

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 names a specific verb ('List'), a specific resource ('nginx server block'), and a precise scope ('sites-enabled'). It also lists the returned aspects (domain, upstream, SSL configuration), making the tool's function unambiguous.

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 explicitly provides a usage alternative: 'Use get_site_config for one domain's full raw config.' This tells an agent when to prefer this tool versus a sibling, leaving no ambiguity.

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