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

Annotations already declare readOnly/idempotent/non-destructive, and the description adds real context beyond them: the 0-4096 domain limit, the output-type switch to a decimal string past 15 digits, a per-call price of $0.001 USDC via x402 on Solana, and an equivalent HTTPS endpoint. The only weakness is a slightly garbled example ('L is 177 and F(11) is 89, so the difference is 0'), which could confuse rather than clarify.

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 definition is front-loaded and each sentence carries information (formula, base cases, example, range, output format, price, endpoint). The odd 'difference is 0' example sentence is the one piece that fails to earn its place because it is not clearly interpretable.

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 single-parameter numeric tool with no output schema, the description covers definition, domain, result encoding, and payment/transport details, which is enough to call it correctly. The main omission is any relationship to the closely named sibling tools, which matters given the very large sibling set.

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 parameter meaning; it does define n through the identity and example, and restates the 0-4096 bound already in the schema. It never explicitly states that n is the index argument or explains error behavior for out-of-range values, so it only partially compensates.

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 gives a precise mathematical definition, L(n) = 2*F(n+1) - 1, with a worked example, so an agent knows exactly what value is computed. It does not differentiate itself from siblings leonardo, leonardo_index, leonardo_mod, or leonardo_sum, which likely compute related quantities, leaving ambiguity about which Leonardo variant to pick.

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 when-to-use guidance: no statement of what problem this solves versus the many related sequence tools, and no exclusion or alternative named. The only contextual details given are the valid n range, pricing, and an HTTPS fallback, which inform cost/access but not tool selection.

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