# Base Gas Fee Quote

> Base Gas Fee Quote is a paid API for AI agents from base-agent-preflight.bytoken2023.workers.dev, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-14).

Returns a current gas fee quote for a given transaction gas limit on the Base (EIP-155:8453) network, including risk assessment flags and risk score.

## Facts

- Endpoint: GET https://base-agent-preflight.bytoken2023.workers.dev/v1/x402/base/gas-fee-quote
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/base-gas-fee-quote-d7d14726
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_sm-06CXwo0cmVJ5njb3Di

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 base-gas-fee-quote-d7d14726
```

Example prompt: Before I submit this transaction, can you get me a gas fee quote on the Base network for a gas limit of 200000 and let me know if there are any risk flags?

## When to prefer this

Use this endpoint when an agent needs a real-time gas fee estimate with integrated risk assessment specifically for the Base (EIP-155:8453) network before executing or signing a transaction. Prefer this over generic gas estimators when you need machine-readable risk flags and a structured preflight safety check in a single call.

## Known failure modes

- Missing or invalid gas_limit parameter (non-numeric string) returns a validation error
- Network congestion or RPC unavailability may cause timeouts or stale quotes
- Payment of $0.003 USDC not fulfilled causes 402 Payment Required response
- gas_limit of 0 or extremely large values may return unexpected results or errors

## How this service works

Machine-payable service intelligence for discovering, verifying, and monitoring identity, risk, authorization, execution-preflight, and evidence APIs before autonomous agents spend.

## Output

Returns a JSON object containing the network identifier (eip155:8453), product name (base-gas-fee-quote), and an assessment object with a risk_score, risk_level (e.g. 'low'), and any risk flags. Allows agents to understand current gas costs and risk profile before committing to a Base transaction.

## Example request

```json
{
 "input": {
  "type": "http",
  "method": "GET",
  "queryParams": {
   "gas_limit": "200000"
  }
 }
}
```

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "gas_limit"
     ],
     "properties": {
      "gas_limit": {
       "type": "string",
       "pattern": "^[0-9]+$",
       "description": "Expected transaction gas limit."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "network": {
       "type": "string"
      },
      "product": {
       "type": "string"
      },
      "activity": {
       "type": "object"
      },
      "identity": {
       "type": "object"
      },
      "assessment": {
       "type": "object"
      },
      "provenance": {
       "type": "object"
      }
     }
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "network": "eip155:8453",
  "product": "base-gas-fee-quote",
  "assessment": {
   "flags": [],
   "risk_level": "low",
   "risk_score": 0
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/base-gas-fee-quote-d7d14726/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from base-agent-preflight.bytoken2023.workers.dev](https://www.zero.xyz/host/base-agent-preflight.bytoken2023.workers.dev/llms.txt)