# Strale Tool Call Validator

> Strale Tool Call Validator is a paid API for AI agents from api.strale.io, paid per call via x402, $0.054/call, status unknown (last checked 2026-09-15).

Validates AI agent tool call inputs against an expected schema, returning a cryptographically audited pass/fail result

## Facts

- Endpoint: GET https://api.strale.io/x402/v2/tool-call-validate
- Price: $0.054/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/strale-tool-call-validator-c75360c4
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_JWC3PGO6YdoTJFnyywwpq

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 strale-tool-call-validator-c75360c4
```

Example prompt: Before executing this tool call, validate it against the expected schema — the tool input is '{"city": "Berlin", "date": "2025-06-01"}' and the expected schema is '{"type":"object","properties":{"city":{"type":"string"},"date":{"type":"string","format":"date"}}}'  — and give me the audit record with the cryptographic hash.

## When to prefer this

Choose this endpoint when you need to validate AI agent tool call inputs against a defined schema with a cryptographically auditable record. It is especially valuable in agentic pipelines where compliance, auditability, and trust verification are required — for example, before executing high-stakes or irreversible tool calls. Prefer it over generic JSON schema validators when you need the cryptographic chain hash audit trail that Strale provides, or when operating within a multi-agent system that requires tamper-evident logging of every capability invocation.

## Known failure modes

- Malformed JSON in tool_input causes parse error and validation failure
- Invalid or unparseable expected_schema returns schema-error response
- Missing required parameters (tool_input or expected_schema) returns 400 bad request
- Network timeout on slow connections returns 5xx error
- Input payload exceeds size limits returns payload-too-large error

## How this service works

The trust layer for AI agents — 250+ independently tested data capabilities across 27 countries. Execute capabilities via REST, MCP, A2A, or x402 micropayments. Every call returns an audit record with cryptographic chain hashing.

## Output

Returns a pass/fail validation result indicating whether the tool_input conforms to the expected_schema, along with a cryptographic audit record including a chain hash for tamper-evident logging of the validation event.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "tool_input": {
   "type": "string"
  },
  "expected_schema": {
   "type": "string"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/strale-tool-call-validator-c75360c4/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.strale.io](https://www.zero.xyz/host/api.strale.io/llms.txt)