ScorpTech x402 API

Riordan

riordan

Read-onlyIdempotent

The nth Riordan number. R(0) is 1, R(1) is 0, and (n+1)R(n) = (n-1)(2R(n-1) + 3R(n-2)) for n at least 2. R(4) is 3, and R(6) is 15. n runs from 0 to 80. Past 15 digits the value is a decimal string. Price: $0.001 USDC per successful call (x402, Solana). Same tool over HTTPS: POST https://scorptech.it.com/api/x402/v1/riordan

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": {
      "n": "<n>"
    },
    "name": "riordan"
  }
}

Input Schema

Name	Required	Description	Default
`n`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

AddedOct 23, 2026

TDQS

A3.8/5.0

Behavior4/5

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

Annotations already establish the read-only, idempotent, non-destructive safety profile. The description adds substantive non-obvious behavior: n is capped at 80, output becomes a decimal string past 15 digits, and calls cost $0.001 USDC via x402 on Solana with an HTTPS endpoint.

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

Conciseness5/5

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

The description is front-loaded with the definition and recurrence, then adds only range, output-format, and payment details. Each sentence carries useful invocation context with no filler.

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

Completeness5/5

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

For a simple one-parameter math tool with no output schema and annotations already covering safety, the description supplies the definition, domain, output representation, and cost/payment context. Nothing essential for correct invocation is missing.

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

Parameters4/5

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

The schema has 0% parameter description coverage, so the description must compensate. It identifies n as the index, gives the domain 0..80, supplies the recurrence, and provides examples such as R(0)=1, R(1)=0, R(4)=3, and R(6)=15.

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

Purpose4/5

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

Names the exact mathematical object (nth Riordan number) and gives the recurrence plus sample values, so what the tool computes is unambiguous. It does not mention sibling tools such as riordan_mod or riordan_sum, so sibling differentiation is left implicit.

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

Usage Guidelines2/5

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

There is no explicit when-to-use guidance, no exclusion criteria, and no routing to alternatives. The range and examples are constraints, not usage guidance, so an agent must infer that this is for direct nth-value computation versus modular or sum variants.

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

All ScorpTech x402 API tools Inspect

Try in Browser

One endpoint for every MCP toolRayrun runs every MCP server behind one URL and holds the credentials. Each call is decided per client, tool, and argument, then recorded.ray.runAd

Glama MCP Gateway

Add one secure layer between your agents and this server.

Resources

Need Help?