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

Annotations already cover read-only, idempotent, non-destructive, closed-world semantics. The description usefully adds what the returned figure excludes (FX conversion, taxes, optional fees) and that pricing is in the recorded currency, which is real behavioral context an agent needs to interpret the number.

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 tight sentences, scope stated first and then the critical exclusions. Nothing is redundant even though some of it restates schema constraints.

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?

Annotations cover the safety profile, but with no output schema the description should say more about the shape of the result (single total? per-year breakdown? line items) and should identify what 'id' refers to. As written an agent can call it, but cannot anticipate what comes back or what id to supply.

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 carries the burden. It clarifies the 'years' range and currency basis, but the required 'id' parameter is never explained (presumably a ring identifier) — the agent must guess its meaning from the sibling tool names.

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 ('calculate ... hardware plus required subscription cost') with scope bounds (1–3 year, recorded currency). It is distinguishable from compare_rings and find_regional_offers in spirit, but never names or contrasts with a sibling explicitly.

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 exclusion sentence ('not a local quote; no exchange-rate conversion, taxes or optional fees') implicitly steers the agent away from find_regional_offers and toward this tool for a configured-price total, but the routing is inference rather than an explicit when-to-use statement or named alternative.

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