# Agentshelf Base Storage Slot Reader

> Agentshelf Base Storage Slot Reader is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-30).

Reads a single 32-byte storage slot value from a contract on Base mainnet using eth_getStorageAt

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/base-storage?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-30
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agentshelf-base-storage-slot-reader-2e4f1813
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_9KyvND-0QpU40iwPUND0G

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 agentshelf-base-storage-slot-reader-2e4f1813 -d '<json body>'
```

Example prompt: What value is stored at slot 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc for the contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base mainnet?

## When to prefer this

Use this endpoint when you need to read a specific raw storage slot from a Base mainnet contract without executing a transaction. Ideal for inspecting proxy implementation addresses (EIP-1967), reading packed storage variables, auditing historical state at specific blocks, or any scenario where you know the slot index and need the 32-byte value directly. Prefer this over general-purpose Ethereum JSON-RPC services when you want a simple HTTP POST with x402 micropayment, no API key, and no node setup.

## Known failure modes

- Invalid contract address format returns an error
- Invalid slot format (not a valid uint256 or 0x-prefixed hex) returns a parsing error
- Invalid block tag or out-of-range block number may return an RPC error
- Contract does not exist at the address returns zero bytes (not an error, just empty storage)
- Network or RPC node timeout returns a service error
- Missing required fields (contract or slot) returns a validation error

## How this service works

Call when an agent needs the storage word at a slot for one Base contract. Send contract, slot, and an optional block tag. Read-only eth_getStorageAt. No spend. Send JSON {"contract":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","slot":"0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc"}. Exact $0.002 USDC on Base. Try unpaid POST /v1/sandbox/base-storage first.

## Output

Returns a 32-byte hex-encoded storage word representing the raw value stored at the specified slot in the given contract's storage on Base mainnet, optionally at a specified block number or tag (latest, finalized, safe).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "slot": {
   "type": "string",
   "examples": [
    "0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc"
   ],
   "description": "Storage slot as a uint256 decimal or 0x-prefixed hex word of at most 32 bytes. Example: 0. The response value is 32 bytes."
  },
  "block": {
   "type": "string",
   "description": "Optional block number or tag latest, finalized, or safe. Example: latest. Omit it for latest. A JSON number such as 100 is accepted."
  },
  "contract": {
   "type": "string",
   "examples": [
    "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"
   ],
   "description": "Contract on Base mainnet. Example: 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913. eth_getStorageAt is read-only."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agentshelf-base-storage-slot-reader-2e4f1813/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agentshelf.syntexa.ch](https://www.zero.xyz/host/agentshelf.syntexa.ch/llms.txt)