# Port 402 Memory Key Lister

> Port 402 Memory Key Lister is a paid API for AI agents from port-402-production.up.railway.app, paid per call via x402, $0.001/call, status unknown (last checked 2026-11-04).

Lists all keys stored in the calling agent's persistent memory namespace, identified by its paying wallet address.

## Facts

- Endpoint: GET https://port-402-production.up.railway.app/v1/memory?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-11-04
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/port-402-memory-key-lister-0e0c5d4b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Tj_kuhgRt57EJVR2CWNHq

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 port-402-memory-key-lister-0e0c5d4b
```

Example prompt: Show me all the keys I currently have stored in my persistent memory so I know what I've saved before.

## When to prefer this

Use this endpoint when an agent needs to discover what data it has previously persisted across sessions before reading or writing specific values. It is the discovery step in a read-modify-write memory workflow. Prefer this over the export endpoint when you only need key names (not values), and before the store endpoint when you want to avoid overwriting existing data unintentionally.

## Known failure modes

- Empty keys array if no values have been stored yet in the namespace
- Payment failure if the x402 micropayment of $0.001 USDC is not properly attached
- Authentication/namespace mismatch if a different wallet is used than expected
- Network timeout or 5xx error if the Railway-hosted service is temporarily unavailable

## How this service works

List the keys in your persistent memory.

## Output

Returns a JSON object containing a 'keys' array listing all key names stored in the calling agent's memory namespace (e.g. {"keys": ["notes", "preferences", "task_state"]}). The namespace is scoped to the paying wallet address used in the x402 payment.

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

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "keys": [
   "notes"
  ]
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/port-402-memory-key-lister-0e0c5d4b/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from port-402-production.up.railway.app](https://www.zero.xyz/host/port-402-production.up.railway.app/llms.txt)