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

Annotations already establish read-only, idempotent, non-destructive behavior, and the description adds substantial context beyond that: per-call pricing, x402/Solana payment details, the HTTPS equivalent endpoint, and the output representation switch to decimal string past 15 digits. This is unusually transparent for a computation tool.

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

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

The description is front-loaded with the core definition and formula, followed by examples, constraints, output behavior, and payment/endpoint details. Every sentence provides useful information, and there is no filler.

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

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

For a simple one-parameter mathematical tool with no output schema, the description is complete enough to invoke correctly: it defines the computation, bounds n, gives sample outputs, explains large-result formatting, and discloses cost/access details.

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

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

Schema description coverage is 0%, so the description must carry the burden for the single parameter n. It defines n as the count of squares summed, states the allowed range 0 to 1000000, and gives examples (through 1 is 1, through 10 is 385), which meaningfully compensates for the empty schema descriptions.

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

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

The description states exactly what the tool computes: the sum of the first n squares, with the closed-form formula and concrete examples. It is clearly distinguishable from most siblings through the name and formula, though it does not explicitly contrast itself with close siblings like odd_square_sum or cube_sum.

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

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

There is no explicit guidance on when to choose this tool over alternatives such as odd_square_sum, cube_sum, or fourth_sum. The formula implies the use case, but the description never states usage conditions or exclusions.

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