# agent402.tools Percentage Helper

> agent402.tools Percentage Helper is a paid API for AI agents from agent402.tools, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Computes percentage operations: percentage of a value, percentage change between two values, or ratio of one value to another.

## Facts

- Endpoint: POST https://agent402.tools/api/percentage
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agent402-tools-percentage-helper-acdeaf92
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_LPCidX4fFL33fkPtY-_le

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 agent402-tools-percentage-helper-acdeaf92 -d '<json body>'
```

Example prompt: What is the percentage change from 80 to 120? Use the 'change' operation with a=80 and b=120.

## When to prefer this

Use this endpoint when you need a simple, reliable percentage calculation without writing custom math logic. Ideal for automation workflows where percentage computations must be consistent and auditable. Prefer over ad-hoc code when operating in an agent pipeline that already uses the x402 payment protocol.

## Known failure modes

- Missing required fields a, b, or op returns a 4xx error
- Invalid op value (not 'of', 'change', or 'ratio') may return an error or unexpected result
- Division by zero when b=0 for 'ratio' or 'change' operations
- Non-numeric values for a or b cause schema validation failure

## How this service works

Percentage helper. op: "of" (a% of b), "change" (% change a→b), "ratio" (a is what % of b).

## Output

A computed percentage result based on the selected operation: either 'of' (a% of b), 'change' (percentage change from a to b), or 'ratio' (a is what percentage of b). Returns a numeric percentage value.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "a": {
   "type": "number"
  },
  "b": {
   "type": "number"
  },
  "op": {
   "type": "string",
   "description": "of | change | ratio"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": 25
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agent402-tools-percentage-helper-acdeaf92/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agent402.tools](https://www.zero.xyz/host/agent402.tools/llms.txt)