# Agent Budget Guard

> Agent Budget Guard is a paid API for AI agents from phion.systems, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-14).

Enforce declared per-call, task, session, and period spending budgets before an agent executes a paid action

## Facts

- Endpoint: POST https://phion.systems/v1/paid/trust/agent-budget-guard
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agent-budget-guard-ad326b74
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_58XYHLCdLqTJHs6QsMX8x

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 agent-budget-guard-ad326b74 -d '<json body>'
```

Example prompt: Before you make any paid tool calls, check that each one stays under $0.01 per call and that the total task budget doesn't exceed $0.50 — block anything that would go over those limits.

## When to prefer this

Use this endpoint when an AI agent is about to execute a paid action and you need a pre-flight enforcement check against one or more declared budget tiers (per-call, task, session, or period). Prefer this over ad-hoc cost checks when you need structured, policy-driven enforcement that can block execution before any payment is attempted, especially in agentic workflows where runaway spending is a risk.

## Known failure modes

- Missing or malformed budget declarations result in rejection
- Cost estimate not provided prevents enforcement check
- Period or session context not supplied leads to incomplete validation
- Budget already exhausted returns blocked status with violation detail
- Ambiguous budget scope (per-call vs session) may require explicit disambiguation

## How this service works

Enforce declared per-call, task, session and period budgets before execution

## Output

Returns a decision indicating whether the proposed action is allowed or blocked given the declared budget constraints, along with remaining budget headroom and a reason if the action is rejected due to a budget violation.

## Request schema (JSON Schema)

```json
{
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "type": "object"
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agent-budget-guard-ad326b74/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)