# Sentinel Agent Pre-Execution Safety Guard

> Sentinel Agent Pre-Execution Safety Guard is a paid API for AI agents from sentinel-agent-wru6.onrender.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-14).

Evaluates a proposed agent action before execution and returns a safety verdict indicating whether it is safe to proceed

## Facts

- Endpoint: POST https://sentinel-agent-wru6.onrender.com/v1/guard
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/sentinel-agent-pre-execution-safety-guard-ce2e8711
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_2OgYCbIw_QTxs9vpGO40f

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 sentinel-agent-pre-execution-safety-guard-ce2e8711 -d '<json body>'
```

Example prompt: Before my agent runs a file-delete action using the DELETE method, can you run a Sentinel safety check on it to get a pre-execution verdict on whether it's safe to proceed?

## When to prefer this

Use this endpoint when you need a lightweight, pay-per-call pre-execution safety gate for AI agent actions before they are executed. It is best suited for agentic pipelines where you want an independent safety verdict on individual actions (by type and method) without building your own policy engine. Prefer this over manual rule checks when you want a managed safety verdict service with minimal integration overhead.

## Known failure modes

- Missing required 'input.type' or 'input.method' fields returns a 400 validation error
- Unrecognized action type may result in a default deny or unknown verdict
- Service may be slow to respond on cold start (hosted on Render free tier)
- Payment failure via x402 protocol results in 402 and action is not evaluated
- Network timeout if the Render instance is spinning up from idle

## How this service works

SENTINEL pre-execution safety verdict

## Output

A safety verdict object indicating whether the proposed agent action (defined by type and method) is cleared to proceed or should be blocked, potentially including a risk classification or recommendation.

## Request schema (JSON Schema)

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

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/sentinel-agent-pre-execution-safety-guard-ce2e8711/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from sentinel-agent-wru6.onrender.com](https://www.zero.xyz/host/sentinel-agent-wru6.onrender.com/llms.txt)