ScorpTech x402 API

Pell Sum

pell_sum

Read-onlyIdempotent

The sum of Pell numbers, or companion Pell-Lucas numbers, from lo through hi inclusive. seq is p or q. lo must not pass hi. Each index runs from 0 to 8192. Price: $0.001 USDC per successful call (x402, Solana). Same tool over HTTPS: POST https://scorptech.it.com/api/x402/v1/pell-sum

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": {
      "lo": "<lo>",
      "hi": "<hi>"
    },
    "name": "pell_sum"
  }
}

Input Schema

Name	Required	Default
`hi`	Yes
`lo`	Yes
`seq`	No	p

Schema Changelog

Changes observed during successful MCP inspections.

AddedOct 23, 2026

TDQS

A3.9/5.0

Behavior4/5

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

Annotations already declare this as a read-only, idempotent, open-world, non-destructive computation. The description adds useful behavioral context beyond annotations: index bounds, inclusive range constraint lo <= hi, payment cost, x402/Solana payment protocol, and an equivalent 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 short, front-loaded with the core operation, and each sentence adds practical detail about sequence selection, bounds, cost, or alternate transport. There is no wasted exposition.

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 simple read-only arithmetic tool, the description covers range semantics, sequence choice, bounds, and payment details. Since there is no output schema, it could explicitly state the return type, but 'The sum' sufficiently indicates the result.

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?

With 0% schema description coverage, the description must carry parameter meaning, and it mostly does: lo/hi define an inclusive range, each index is bounded 0 to 8192, lo must not pass hi, and seq selects Pell vs companion Pell-Lucas values. It could be slightly clearer by explicitly mapping p to Pell and q to companion Pell-Lucas.

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?

The description clearly states that this computes the sum of Pell numbers or companion Pell-Lucas numbers over an inclusive index range. It distinguishes the operation as a sum, but does not explicitly contrast it with sibling tools such as pell, pell_lucas, or pell_compose.

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

Usage Guidelines3/5

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

Usage is implied by the range-and-sum framing and by the seq choice between Pell and companion Pell-Lucas sequences. However, there is no explicit guidance on when to use this tool instead of individual Pell/Pell-Lucas term tools, nor any stated exclusions.

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

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