ExchangeRebel — pay-per-call APIs for AI agents (x402 on Solana)

receipt_precheck

FREE headline pre-check (100/day per wallet; pass caller). Returns assessability only - whether the challenge + header pair is well-formed for grading; no field is matched and no verdict is returned. The full signed report is the paid receipt_verify call.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "caller": "<caller>",
      "challenge": "<challenge>",
      "paymentResponse": "<paymentResponse>"
    },
    "name": "receipt_precheck"
  }
}

Input Schema

Name	Required	Description
`caller`	Yes	Solana base58 wallet of the operator; keys the free allowance (100/day per wallet).
`challenge`	Yes	The captured 402 challenge object exactly as issued by the endpoint that was paid. Processed in memory only, never stored.
`paymentResponse`	Yes	The PAYMENT-RESPONSE header value from the paid call (base64 JSON string; a raw JSON string or the decoded object are also accepted). Processed in memory only, never stored.

Schema Changelog

Changes observed during successful MCP inspections.

AddedNov 3, 2026

TDQS

A4.3/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the burden and does so well: it discloses the 100/day per-wallet quota, that only well-formedness is assessed, that no field is matched and no verdict returned, and that the caller wallet keys the allowance. It stops short of describing rate-limit rejection behavior or the shape of a failed pre-check response.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three tight sentences with the cost and quota front-loaded, followed by the return contract and the escalation path. Every sentence earns its place; minor density from stacked parentheticals but no filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a three-parameter precheck with no annotations and no output schema, the description establishes cost model, quota, what is and is not evaluated, and the paid alternative. The remaining gap is error/limit-exceeded behavior, which an agent would want before calling in bulk.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% and the schema already explains all three parameters, including the caller's allowance keying and in-memory processing. The description only reinforces 'pass caller' and the quota, adding no format or validation detail beyond what the schema states, so baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('headline pre-check' of a challenge + payment-response pair) and immediately scopes it: 'Returns assessability only... no verdict is returned.' It also names the sibling it is not, receipt_verify, so an agent can separate the two without opening either schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly frames the choice: this is the FREE pre-check, and 'The full signed report is the paid receipt_verify call.' Cost and depth of result are given as the discriminating conditions, along with the free-tier ceiling that determines when to escalate.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

All ExchangeRebel — pay-per-call APIs for AI agents (x402 on Solana) tools Inspect

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