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Agent Prep – Token Estimator
x402
Agent Prep – Token Estimator is a paid API for AI agents from agent-prep.annushka1190.workers.dev, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-13).
Estimates token count, word count, and character count for a given HTTP request body, enabling pre-LLM cost and context-window planning.
Price / call$0.002
Success—
StatusUnknown
How this service works
Pre-LLM utilities for AI agents: structural JSON diff, JSON path listing, token estimation, text chunking, and truncation. Pay with USDC via x402 — no API keys.
Output
Returns a JSON object with three fields: 'tokens' (estimated LLM token count), 'words' (word count), and 'chars' (character count) for the submitted request body.
Example use cases
Context window budget check
“I'm about to send a big JSON document to GPT-4 — can you estimate how many tokens it will consume so I know whether I need to chunk it first?”
LLM cost pre-flight estimation
“Estimate the token count for this prompt payload so I can figure out how much this API call will cost before I send it.”
Agent prompt size validation
“Before my agent submits this system prompt plus user message to the model, check how many tokens and words the combined body adds up to.”
Technical details
Endpoint
POSThttps://agent-prep.annushka1190.workers.dev/v1/tokens/estimateWhen to prefer
Use this endpoint when you need a lightweight, pay-per-call token estimator with no API key setup — ideal for AI agents that need to perform pre-LLM context-window checks or cost estimation on arbitrary JSON payloads before dispatching to an LLM provider.
Side effects
- Missing required 'input' field returns validation error
- Non-POST method specified in 'method' field is rejected
- Malformed JSON body causes parse error
- Payment not attached or insufficient USDC causes 402 Payment Required response
- Empty body may return zero counts without error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object |
Output
Schema · Response
{
"type": "json",
"example": {
"chars": 48,
"words": 8,
"tokens": 12
}
}Tags
x402
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