# Seneschal Ethereum Block Builder Share Query

> Seneschal Ethereum Block Builder Share Query is a paid API for AI agents from api.seneschal.space, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-15).

Retrieves current builder share and MEV telemetry data from Seneschal's Ethereum mainnet block builder.

## Facts

- Endpoint: GET https://api.seneschal.space/v1/q/builder-share
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/seneschal-ethereum-block-builder-share-query-95a6dab3
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_VhSzsaNuIk3gesOi8uhqN

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 seneschal-ethereum-block-builder-share-query-95a6dab3
```

Example prompt: Can you pull the current builder share stats from Seneschal's Ethereum mainnet block builder so I can see the latest MEV and liquidation telemetry?

## When to prefer this

Use this endpoint when you need real-time Ethereum block builder share data or free liquidation telemetry from a specialized MEV-aware builder service. Prefer over generic block explorers when you need builder-specific MEV metrics and liquidation event data with x402 micropayment access.

## Known failure modes

- Payment required (402) if USDC balance insufficient on Base
- Invalid or missing x402 payment header returns auth error
- Rate limiting if query frequency exceeds plan
- Network timeout if Ethereum mainnet data unavailable
- Malformed request returns 400 with schema error

## How this service works

Single-fact: what share of slots in the window did `builder` win? Substring match.

## Output

Returns current builder share statistics and liquidation telemetry data from the Seneschal Ethereum mainnet block builder, including MEV-related metrics.

## Example request

```json
{
 "builder": "default",
 "properties": "builder_share,mev_telemetry"
}
```

## 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",
     "required": [
      "builder"
     ],
     "properties": {
      "window": {
       "type": "string",
       "description": "Lookback window: 24h, 7d or 30d (default 24h)."
      },
      "builder": {
       "type": "string",
       "description": "Builder name (substring match)."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "window": {
       "type": "string"
      },
      "builder": {
       "type": "string"
      },
      "as_of_ms": {
       "type": "integer"
      },
      "share_pct": {
       "type": "number"
      },
      "slots_won": {
       "type": "integer"
      },
      "total_slots": {
       "type": "integer"
      }
     }
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "window": "24h",
  "builder": "titan",
  "as_of_ms": 1765532000000,
  "share_pct": 28.6,
  "slots_won": 412,
  "total_slots": 1440
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/seneschal-ethereum-block-builder-share-query-95a6dab3/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.seneschal.space](https://www.zero.xyz/host/api.seneschal.space/llms.txt)