Libretranslate

List Languages

list_languages

Read-onlyIdempotent

List languages supported by the configured LibreTranslate instance.

Input Schema

Name	Required	Description	Default
No arguments

Output Schema

Name	Required	Description	Default
`count`	Yes	Total number of supported languages
`languages`	Yes	List of supported languages with codes and targets

Schema Changelog

Changes observed during successful MCP inspections.

Changed2 schema fields changedMay 24, 2026

addedInput schema / examples
```
Added value: +[
+  {}
+]
```

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "properties": {
+    "count": {
+      "description": "Total number of supported languages",
+      "type": "integer"
+    },
+    "languages": {
+      "description": "List of supported languages with codes and targets",
+      "items": {
+        "properties": {
+          "code": {
+            "description": "Language code",
+            "type": [
+              "string",
+              "null"
+            ]
+          },
+          "name": {
+            "description": "Human-readable language name",
+            "type": [
+              "string",
+              "null"
+            ]
+          },
+          "target_codes": {
+            "description": "Language codes this language can be translated to",
+            "items": {
+              "type": "string"
+            },
+            "type": "array"
+          }
+        },
+        "type": "object"
+      },
+      "type": "array"
+    }
+  },
+  "required": [
+    "count",
+    "languages"
+  ],
+  "type": "object"
+}

First observedMay 12, 2026

TDQS

A4.5/5.0

Behavior4/5

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is clear. The description adds valuable context that the results depend on the 'configured LibreTranslate instance', indicating the list is dynamic rather than static. There is no contradiction 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 a single, front-loaded sentence that directly states the function without any unnecessary words or redundancy. It earns its place and is easily scannable.

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 tool's low complexity, zero parameters, and the presence of an output schema, the description provides sufficient context for correct invocation. The annotations fill in safety and behavioral details, making the overall tool definition complete.

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 input schema fully documents its input. The description does not need to elaborate on parameters, and the baseline of 4 applies because there is nothing to disambiguate.

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 uses a specific verb 'List' and identifies the resource as 'languages supported by the configured LibreTranslate instance', which clearly distinguishes it from sibling tools like detect_language and translate. The purpose is unambiguous and self-contained.

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 clear context: this tool retrieves the set of supported languages from the configured instance. While it does not explicitly name alternatives or state when not to use it, the tool's unique purpose among siblings makes the usage obvious and no exclusions are necessary.

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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