# TraceFast Address Relations at Block

> TraceFast Address Relations at Block is a paid API for AI agents from mpp.tracefast.xyz, paid per call via x402, $0.025/call, status unknown (last checked 2026-10-12).

Returns the on-chain relations an Ethereum address held as subject at the end of a specific block, including proxy targets, beacon references, admin roles, and delegation links, each with the time window it was active.

## Facts

- Endpoint: GET https://mpp.tracefast.xyz/api/v1/chains/1/entities/:address/relations/at-block?utm_source=zero.xyz
- Price: $0.025/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-12
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/tracefast-address-relations-at-block-0b5f8df4
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_B4_SDNDHDEpoDnyK8-sls

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 tracefast-address-relations-at-block-0b5f8df4
```

Example prompt: Can you check TraceFast and tell me what relations the address 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 was the subject of at the end of block 19000000 — like what proxy implementation it pointed to, any beacon it read, or who administered it?

## When to prefer this

Use this endpoint when you need historical point-in-time relation data for a specific Ethereum address at a known block — particularly for proxy implementation lookups, beacon references, admin relationships, or delegation targets. Prefer this over current-state endpoints when auditing historical configurations, investigating upgrades, or reconstructing governance state at a past block.

## Known failure modes

- Invalid address format (not 0x-prefixed 40 hex characters) returns 400 error
- Block number not yet indexed or in the future returns 404 or empty result
- Address with no known relations at that block returns empty list
- Network errors or timeout if block data is being processed
- Payment failure via x402 protocol if USDC balance is insufficient

## How this service works

TraceFast knowledge graph: the relations an address was the subject of at the end of one block — which implementation a proxy pointed at, which beacon it read, who administered it, where an account had delegated — each with the window it held for. Path address: The address, `0x`-prefixed, 40 hex characters, any case. Query block: The block to answer about. Docs: https://docs.tracefast.xyz/api/address-relations-at-block.md

## Output

A list of relations where the queried address was the subject at the end of the specified block, each relation including the relation type (e.g. proxy-implementation, beacon, admin, delegation), the related counterparty address, and the window (start and end blocks) during which that relation was active.

## Request schema (JSON Schema)

```json
{
 "properties": {
  "input": {
   "required": [
    "method"
   ],
   "properties": {
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "pathParams": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/tracefast-address-relations-at-block-0b5f8df4/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from mpp.tracefast.xyz](https://www.zero.xyz/host/mpp.tracefast.xyz/llms.txt)