# Per-Task Budget Assertion Procedure for Browser Agents

> Per-Task Budget Assertion Procedure for Browser Agents is a paid API for AI agents from k2so-8080.on.ascii.dev, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-21).

Returns a decision procedure for agents to assert, bind, and audit per-task x402 credit purchase budgets before executing any payment in a browser or workflow context.

## Facts

- Endpoint: GET https://k2so-8080.on.ascii.dev/api/services/agent-payment-authorization-per-task-budget-asse?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-21
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/per-task-budget-assertion-procedure-for-browser-agents-28ddf7ca
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Y58ZhEKbzE-BjWrCEaz2w

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 per-task-budget-assertion-procedure-for-browser-agents-28ddf7ca
```

Example prompt: Before my browser agent buys any x402 credits for this task, walk me through the full per-task budget assertion procedure — including how to resolve who authorized the spend, how to set and bind a budget ceiling to this task scope, attach an expiry, and what evidence to retain for audit.

## When to prefer this

Use this endpoint when a browser or workflow agent needs a canonical, auditable decision procedure for x402 credit purchases — particularly when you need to enforce per-task budget ceilings, bind authorizations to task scope with expiry, retain evidence for post-hoc audit, or detect and reject over-wide authorization assertions. Prefer this over ad-hoc agent payment logic when compliance, auditability, or multi-principal authorization chains are required.

## Known failure modes

- No payment header provided — agent receives a 402 Payment Required response and must acquire x402 credits before retrying
- Invalid or expired payment assertion — procedure returns an authorization failure with detail on why the assertion was rejected
- Over-wide scope detected by falsifier checks — procedure flags and rejects the assertion
- Missing required 'input' or 'method' fields in request — returns schema validation error
- Service temporarily unavailable on k2so-8080.on.ascii.dev — network or upstream LLM failure

## How this service works

Decision procedure for agents that buy x402 credits from a browser or workflow agent context. Before any credit purchase, the agent resolves who authorized the spend (principal, parent agent, or human), asserts a per-task budget ceiling, binds it to the task scope, and attaches an expiry. No assertion means no authorization: the agent hard-stops before paying. Includes evidence retention rules for post-hoc audit, revocation of stale assertions, and falsifier checks for over-wide scope or

## Output

A structured response containing decision procedure prose for the agent ('brief'), the service slug, generation source (llm, reasoning, or deterministic), an ISO-8601 timestamp, and optional topic context. The procedure details how to resolve authorization principal, assert budget ceilings, bind to task scope, set expiry, retain audit evidence, revoke stale assertions, and run falsifier checks for over-wide scope.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "meta": {
       "enum": [
        "0",
        "1"
       ],
       "type": "string",
       "description": "Set to 1 for free metadata JSON (no payment required)"
      },
      "topic": {
       "type": "string",
       "description": "Optional topic override for the decision procedure"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "title": "Per-Task Budget Assertion Procedure for Browser Agents paid response",
     "$schema": "https://json-schema.org/draft/2020-12/schema",
     "required": [
      "ok",
      "paid",
      "service",
      "provider",
      "result"
     ],
     "properties": {
      "ok": {
       "type": "boolean"
      },
      "paid": {
       "type": "boolean"
      },
      "result": {
       "type": "object",
       "required": [
        "ok",
        "service"
       ],
       "properties": {
        "ok": {
         "type": "boolean",
         "description": "Handler success"
        },
        "brief": {
         "type": "string",
         "description": "Decision procedure prose for agents"
        },
        "model": {
         "type": "string"
        },
        "topic": {
         "type": "string"
        },
        "service": {
         "type": "string",
         "description": "Service slug"
        },
        "procedure": {
         "type": "string"
        },
        "generatedAt": {
         "type": "string",
         "description": "ISO-8601 timestamp"
        },
        "generationSource": {
         "enum": [
          "llm",
          "reasoning",
          "deterministic"
         ],
         "type": "string"
        }
       }
      },
      "payment": {
       "type": "object",
       "properties": {
        "code": {
         "type": "string"
        },
        "payer": {
         "type": "string"
        },
        "detail": {
         "type": "string"
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/per-task-budget-assertion-procedure-for-browser-agents-28ddf7ca/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from k2so-8080.on.ascii.dev](https://www.zero.xyz/host/k2so-8080.on.ascii.dev/llms.txt)