Deepl

Target Languages

target_languages

Read-onlyIdempotent

Supported target languages.

Input Schema

Name	Required	Description	Default
No arguments

Output Schema

Name	Required	Description	Default
`count`	Yes	Number of items returned.
`items`	Yes	List of supported target languages

Schema Changelog

Changes observed during successful MCP inspections.

Changed2 schema fields changedMay 27, 2026

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

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "properties": {
+    "count": {
+      "description": "Number of items returned.",
+      "type": "integer"
+    },
+    "items": {
+      "description": "List of supported target languages",
+      "items": {
+        "properties": {
+          "language": {
+            "description": "Language code",
+            "type": "string"
+          },
+          "name": {
+            "description": "Language name",
+            "type": "string"
+          },
+          "supports_formality": {
+            "description": "Whether language supports formality settings",
+            "type": "boolean"
+          }
+        },
+        "required": [
+          "language",
+          "name"
+        ],
+        "type": "object"
+      },
+      "type": "array"
+    }
+  },
+  "required": [
+    "items",
+    "count"
+  ],
+  "type": "object"
+}

First observedMay 20, 2026

TDQS

C2.3/5.0

Behavior2/5

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. However, the description adds no behavioral context beyond the annotations—it does not disclose what the tool returns, whether the list is dynamic, or what format the output takes. No contradiction exists.

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

Conciseness2/5

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

At three words, the description is technically concise but severely under-specified. It is a fragment rather than a functional sentence, sacrificing substance for brevity. This is under-specification, not effective conciseness.

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

Completeness2/5

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

Despite having an output schema and read-only annotations, the tool requires at least a semantic hint about what 'target languages' means (e.g., languages that can be translated into). The description provides no such context, leaving the agent to guess the tool's purpose and expected output.

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, and the schema's properties are empty. With no parameters to explain, the baseline is 4. The description adds no param semantics, but none are needed.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose2/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description 'Supported target languages' is essentially a restatement of the tool name with the adjective 'supported' added. It lacks a verb or explicit action (e.g., 'List' or 'Get'), making the purpose vague and not clearly differentiated from sibling tools like source_languages.

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

Usage Guidelines2/5

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

No guidance is provided on when to use this tool versus alternatives. There is no mention of context, prerequisites, or exclusions. The description is a bare noun phrase, leaving the agent without any direction on invocation.

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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