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

Annotations already declare readOnlyHint=true, idempotentHint=true, and openWorldHint=true, so safety and repeatability are covered. The description adds important behavioral context by disclosing pricing: 0.005 USDC per successful call via x402 on Base, with errors free.

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 purpose is front-loaded in the first clause, followed immediately by the formula and pricing details. Every sentence adds useful information with no redundancy.

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 read-only calculation tool with rich annotations and fully described parameters, the definition is nearly complete. The return value is implied by the formula rather than explicitly stated, which is a minor gap but not enough to impede correct use.

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%, so the baseline is 3, but the description adds meaning by giving the adjustment formula amount × index(to) / index(from). This clarifies the relationship among amount, from, and to beyond the individual 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?

States a specific verb and resource: adjusts an amount by Statistics Norway's CPI, with the exact formula. It clearly distinguishes the operation from the sibling get_consumer_price_index, which retrieves index data rather than performing an adjustment.

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 examples of rent, salary, and contract price imply when the tool is useful, but there is no explicit guidance on when to use this instead of get_consumer_price_index or when not to use it. Usage is reasonably inferable but not fully specified.

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