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

No annotations are provided, so the description carries the full burden of behavioral disclosure, and it discloses nothing: no output format, no input domain, no edge-case behavior for negative or non-numeric values.

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?

It is short, but brevity here is under-specification rather than conciseness: the text duplicates the tool name and conveys zero information, so nothing in it earns its place.

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 tool sitting in a large family of math utilities with several Lucas-related siblings, an agent needs at minimum what is computed and what 'value' means. Neither is present, and there is no output schema to fall back on.

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 100%, so the single 'value' parameter is documented in the schema itself ('Value to process'). That reaches the baseline 3, but the description adds no meaning whatsoever about what the value represents (an index? a numeric input?) or its expected format.

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 is 'Lucas Index: Lucas Index', a verbatim restatement of the tool name with no verb, no resource explanation, and no indication of what the tool produces. It does not distinguish this tool from siblings like x402-lucas-number, x402-lucas-series, or x402-is-lucas-prime.

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 guidance on when to use this tool, when not to, or which sibling to prefer. An agent has no way to know whether this returns the nth Lucas number, the index of a value within the Lucas sequence, or something else entirely.

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