define_wordLook up a word's definition, pronunciation, part of speech, and usage examples. Returns meaning, phonetic spelling, and example sentences.
| Name | Required | Description | Default |
|---|---|---|---|
| word | Yes | The word to look up |
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
Output schema / (root)Previous value: -nullNew value: +{
+ "oneOf": [
+ {
+ "properties": {
+ "found": {
+ "description": "Word not found in dictionary",
+ "enum": [
+ false
+ ],
+ "type": "boolean"
+ },
+ "hint": {
+ "description": "Suggestion for retry or explanation of why word was not found",
+ "type": "string"
+ },
+ "word": {
+ "description": "The word that was looked up",
+ "type": "string"
+ }
+ },
+ "required": [
+ "word",
+ "found",
+ "hint"
+ ],
+ "type": "object"
+ },
+ {
+ "properties": {
+ "found": {
+ "description": "Word found in dictionary",
+ "enum": [
+ true
+ ],
+ "type": "boolean"
+ },
+ "meanings": {
+ "description": "List of meanings organized by part of speech",
+ "items": {
+ "properties": {
+ "definitions": {
+ "description": "Up to 3 definitions for this part of speech",
+ "items": {
+ "properties": {
+ "definition": {
+ "description": "Definition of the word",
+ "type": "string"
+ },
+ "example": {
+ "description": "Usage example sentence",
+ "type": [
+ "string",
+ "null"
+ ]
+ }
+ },
+ "required": [
+ "definition",
+ "example"
+ ],
+ "type": "object"
+ },
+ "type": "array"
+ },
+ "part_of_speech": {
+ "description": "Part of speech (e.g., noun, verb, adjective)",
+ "type": "string"
+ }
+ },
+ "required": [
+ "part_of_speech",
+ "definitions"
+ ],
+ "type": "object"
+ },
+ "type": "array"
+ },
+ "phonetic": {
+ "description": "Phonetic spelling of the word",
+ "type": [
+ "string",
+ "null"
+ ]
+ },
+ "word": {
+ "description": "The word that was looked up",
+ "type": "string"
+ }
+ },
+ "required": [
+ "word",
+ "found",
+ "phonetic",
+ "meanings"
+ ],
+ "type": "object"
+ }
+ ],
+ "type": "object"
+}Input schema / examplesAdded value: +[
+ {
+ "word": "serendipity"
+ },
+ {
+ "word": "ephemeral"
+ }
+]Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds return-value details (meaning, phonetic spelling, example sentences), which provides some behavioral context, but no edge-case behaviors or limitations are disclosed.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two concise sentences convey the tool's purpose and output without extraneous information.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
With one well-documented parameter, comprehensive read-only annotations, and an output schema, the description provides sufficient context for an agent to select and invoke the tool correctly.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The sole parameter 'word' is fully described in the schema with 100% coverage. The description confirms the word is the lookup target but adds no additional parameter semantics beyond what the schema already provides.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description uses a specific verb 'look up' and identifies the resource as 'a word's definition, pronunciation, part of speech, and usage examples,' which clearly differentiates it from sibling tools like get_synonyms.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description implies usage for obtaining word definitions and related linguistic information. It does not explicitly state when to prefer this over get_synonyms or other alternatives, but the context is clear enough for selection.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.