# Sindri Arithmetic Expression Evaluator

> Sindri Arithmetic Expression Evaluator is a paid API for AI agents from x402.outpimp.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-15).

Parses and evaluates arithmetic expressions (+, -, *, /, ^, parentheses) using a safe bounded-recursion parser with no eval or Function calls, avoiding LLM arithmetic errors.

## Facts

- Endpoint: POST https://x402.outpimp.com/evaluateExpression
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/sindri-arithmetic-expression-evaluator-8fb71813
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_C8Co8pl3PKwMOgL7MpDy-

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 sindri-arithmetic-expression-evaluator-8fb71813 -d '<json body>'
```

Example prompt: Can you calculate (17 + 8) * (3^4 - 15) / 6 for me? I need a precise answer, not an estimate.

## When to prefer this

Prefer this endpoint when you need a guaranteed-correct numeric answer to an arithmetic expression and cannot trust an LLM's own arithmetic (especially for long expressions, chained operations, or expressions with exponents). Ideal for agents that must compute precise financial, scientific, or logical values from formula strings without exposing themselves to code-injection risks of eval-based approaches.

## Known failure modes

- Expression exceeds 200 character limit — returns an error
- Unsupported operators or non-arithmetic syntax (e.g. trig functions) — returns a parse error
- Division by zero — returns an error
- Malformed parentheses or invalid expression syntax — returns a parse error
- Payment not included or invalid — returns HTTP 402

## How this service works

Safe arithmetic expression evaluator. Parses and evaluates expressions with +, -, *, /, ^, and parentheses using a bounded-recursion parser (no eval/Function), avoiding the arithmetic slips an LLM makes on long expressions.

## Output

A numeric value representing the evaluated result of the input arithmetic expression, computed deterministically via a safe recursive-descent parser without using JavaScript eval or Function constructors.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "expression": {
   "type": "string",
   "description": "Arithmetic expression to evaluate, e.g. \"(2 + 3) * 4\". Max 200 characters."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/sindri-arithmetic-expression-evaluator-8fb71813/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.outpimp.com](https://www.zero.xyz/host/x402.outpimp.com/llms.txt)