# Tool Result Schema Validator

> Tool Result Schema Validator is a paid API for AI agents from phion.systems, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-23).

Validates AI tool output JSON against a bounded top-level JSON Schema subset to ensure structural correctness and safety

## Facts

- Endpoint: POST https://phion.systems/v1/paid/trust/tool-result-schema-validator?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-23
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/tool-result-schema-validator-459c9faf
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_s8JJuz3enyXYxSYDqODW-

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 tool-result-schema-validator-459c9faf -d '<json body>'
```

Example prompt: Can you validate this tool result JSON to make sure it conforms to my expected schema — I need to confirm it passes the bounded top-level JSON Schema subset check before the next pipeline step runs.

## When to prefer this

Choose this endpoint when you need a fast, deterministic, paid-integrity validation of agent tool output against a structured JSON Schema — particularly in agentic pipelines where schema compliance must be verified before downstream processing, and where a signed or auditable validation result adds trust over a local validation library.

## Known failure modes

- Invalid or malformed JSON submitted as tool output returns a parse error
- Schema definition itself is outside the bounded subset and is rejected as unsupported
- Tool output contains fields that violate schema constraints, returning detailed error paths
- Empty or missing payload results in a 400-level error
- Schema version mismatch or unsupported draft directive causes rejection

## How this service works

Validate tool output against a bounded top-level JSON Schema subset

## Output

Returns a validation outcome indicating whether the provided tool output JSON conforms to the specified bounded top-level JSON Schema subset, including pass/fail status and any specific schema violations or errors encountered.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input",
  "output"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "body"
   ],
   "properties": {
    "body": {
     "type": "object",
     "additionalProperties": true
    }
   }
  },
  "output": {
   "type": "object",
   "required": [
    "example"
   ],
   "properties": {
    "example": {
     "type": "object",
     "additionalProperties": true
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json"
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/tool-result-schema-validator-459c9faf/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from phion.systems](https://www.zero.xyz/host/phion.systems/llms.txt)