# AgentUtility Thesaurus — Synonyms & Related Words Lookup

> AgentUtility Thesaurus — Synonyms & Related Words Lookup is a paid API for AI agents from x402.agentutility.ai, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-14).

Returns synonyms, antonyms, or related words for a given word using the Datamuse API, payable in USDC via x402

## Facts

- Endpoint: POST https://x402.agentutility.ai/thesaurus
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agentutility-thesaurus-synonyms-related-words-lookup-fb79f31c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Qo9VNczaif0qfA6qmLY5o

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability agentutility-thesaurus-synonyms-related-words-lookup-fb79f31c -d '<json body>'
```

Example prompt: What are some synonyms for the word 'happy'? Give me a ranked list of words that mean the same thing.

## When to prefer this

Use this endpoint when you need a ranked list of synonyms, antonyms, or related words for a specific word — especially in writing assistance, content generation, or NLP enrichment workflows that need a lightweight, pay-per-call API rather than a full subscription to a thesaurus service.

## Known failure modes

- Unknown or misspelled word returns empty results array
- Invalid mode value returns an error
- Missing required 'word' field returns a 400-level error
- Network or upstream Datamuse API failure returns a 5xx error
- Payment not settled via x402 returns 402 Payment Required

## How this service works

Paid x402 endpoints organized into product clusters. USDC-settled on Base. MCP-callable. ERC-8004 identity registry agentId 47167.

## Output

A JSON object containing the queried word, the mode used (e.g. synonyms), the underlying data source (Datamuse), and an array of related words each with a similarity score — e.g. [{"word":"felicitous","score":53634},{"word":"glad","score":38273}].

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "required": [
      "word"
     ],
     "properties": {
      "mode": {
       "enum": [
        "synonyms",
        "antonyms",
        "sounds_like",
        "similar_meaning",
        "related"
       ],
       "type": "string",
       "description": "Relation type. Default 'synonyms'."
      },
      "word": {
       "type": "string",
       "description": "Single English word to look up."
      },
      "limit": {
       "type": "number",
       "description": "Max results to return. 1-50. Default 20."
      }
     }
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "mode": {
       "type": "string"
      },
      "word": {
       "type": "string"
      },
      "source": {
       "type": "string"
      },
      "results": {
       "type": "array",
       "items": {
        "type": "object",
        "properties": {
         "word": {
          "type": "string"
         },
         "score": {
          "type": "integer"
         }
        }
       }
      }
     }
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "mode": "synonyms",
  "word": "happy",
  "source": "https://www.datamuse.com",
  "results": [
   {
    "word": "felicitous",
    "score": 53634
   },
   {
    "word": "glad",
    "score": 38273
   },
   {
    "word": "joyful",
    "score": 31250
   },
   {
    "word": "cheerful",
    "score": 24611
   }
  ]
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agentutility-thesaurus-synonyms-related-words-lookup-fb79f31c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.agentutility.ai](https://www.zero.xyz/host/x402.agentutility.ai/llms.txt)