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

With no annotations, the description carries the full behavioral disclosure burden. It does disclose the conversion behavior and expected input syntax, but it conflicts with the empty input schema by demanding value/from/to parameters the schema does not declare. It also omits output format and behavior with invalid or missing units.

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?

Two sentences, front-loaded with the operation and supported units, followed by a usage example. Every clause earns its place; there is no fluff or redundant restating of the tool name.

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 converter the description is close to sufficient, but the empty schema combined with the instruction to provide value/from/to units creates a critical gap: an agent cannot validate or construct the call from structured data. Precise unit tokens and output behavior are also missing, so the description is not complete enough for reliable invocation.

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?

The input schema exposes zero properties, so the description must carry parameter meaning. It adds value by naming the conceptual arguments and providing an example with unit codes (ha, m2), but it leaves exact parameter names and the full unit-token lexicon ambiguous (e.g., the code for square feet), and it does not specify the expected type of 'value'.

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 uses a specific verb ('Convert') and resource ('area value'), and enumerates the exact supported units (square meters, square kilometers, hectares, acres, square feet). This makes the tool's purpose clear and distinguishes it from narrower single-pair converters like x402-acres-to-hectares, though it does not explicitly name sibling alternatives.

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?

It states what the tool does and how to supply inputs ('value and from/to units') with a concrete example (from=ha,to=m2). However, it does not say when to prefer this over generic converters like x402-units-convert or the single-pair conversions, and it gives no exclusions or alternative routing guidance.

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