# AgentKV Read/Verify Key (u3b:verify)

> AgentKV Read/Verify Key (u3b:verify) is a paid API for AI agents from api.agentx402.ai, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-13).

Reads or verifies a specific encrypted key-value entry at path u3b:verify from an agent-native key-value store, paying $0.003 USDC per request via x402 with no signup required.

## Facts

- Endpoint: GET https://api.agentx402.ai/v1/kv/u3b%3Averify
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agentkv-read-verify-key-u3b-verify-50907219
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_HM4fbmeQvcB7TeRB9ZU8s

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 agentkv-read-verify-key-u3b-verify-50907219
```

Example prompt: Can you retrieve the encrypted value stored at the key 'u3b:verify' in my AgentKV store? Use my wallet as the namespace and pay the $0.003 read fee automatically.

## When to prefer this

Use this endpoint when an AI agent needs to read or verify a previously stored encrypted value from the AgentKV store without any prior signup or API key — especially when the agent's wallet is the identity and namespace, and micro-payments via x402 are acceptable. Prefer this over traditional KV stores when operating in a trustless, agent-native, pay-per-use environment.

## Known failure modes

- Key not found: returns 404 if the requested key does not exist in the namespace
- Insufficient credits or payment failure: returns 402 if x402 payment is not accepted or wallet has no credits
- Unauthorized namespace: returns 403 if the wallet/account key does not match the namespace
- Invalid method: returns 400 if an unsupported HTTP method is used
- Network timeout: slow response if x402 payment negotiation takes too long

## How this service works

Agent-native encrypted key-value store, paid per request over x402 — no signup, no API key. The payer's wallet (or an ak_ account key) is the namespace; values are client-side encrypted. Write $0.005, read $0.003; prepay $1 = 10,000 credits at 1/10 the per-op price (POST /v1/credits/deposit). SDK: npm i @agentkv/client. Docs: https://agentx402.ai

## Output

Returns the stored (client-side encrypted) value associated with the key 'u3b:verify' within the caller's wallet-namespaced KV store. May also confirm existence/absence of the key for HEAD requests, or return an empty/null response if the key does not exist.

## 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": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agentkv-read-verify-key-u3b-verify-50907219/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.agentx402.ai](https://www.zero.xyz/host/api.agentx402.ai/llms.txt)