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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior. The description adds value beyond those by specifying exact 18-decimal integer mathematics, the no-floating-point-error guarantee, and the exact conversion constants (1 ETH = 1e18 wei, 1 gwei = 1e9 wei).

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 short and front-loaded with the action and scope. The conversion factors are useful, and the source URL is the only mildly extraneous element, but it is a single clause and does not meaningfully reduce clarity.

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 two-parameter converter, the description, annotations, and full input/output schemas leave nothing essential missing. The description covers the conversion behaviour, the precision guarantee, and the valid units.

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 coverage is 100% and both parameters have descriptions, so the baseline is 3. The description goes beyond the schema by explaining what the units mean mathematically and by specifying that the output will include all three units, which clarifies how the amount should be interpreted.

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 opens with a specific verb and resource: 'Convert an amount given in wei, gwei or ETH', and states the output is all three units. This makes the tool's function unmistakable and distinguishes it from the many other converters in the sibling list.

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?

The first sentence clearly defines the trigger condition: an amount expressed in wei, gwei, or ETH that needs conversion into all three units. It provides clear context but does not explicitly name an alternative or state when not to use it, so it falls just short of full routing guidance.

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