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

Annotations already declare readOnly, non-destructive, idempotent, and a closed world, so the safety profile is largely covered. The description reinforces this by stating it does not start a trial or purchase, which adds business-level clarification about the absence of commitment. However, it says nothing about what 'terms' the response includes, the public/non-authenticated nature, or the return behavior.

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 short sentences, with the resource and the negative scope front-loaded and zero filler. Nothing is repeated and nothing is wasted.

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 three-parameter lookup with no output schema and strong annotations, it covers the core 'what' but leaves real gaps: it doesn't specify which fields 'terms' returns, whether pricing varies by locale beyond language, or that all three parameters are mandatory. An agent could call it but might have to retry after seeing the result format.

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 should explain the three required parameters, and it explains none of them. It never says that 'locale' controls the language of the returned terms, that 'period' selects billing cadence, or what distinguishes the four plan tiers; the enum values are self-describing, but they carry only part of that information.

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?

It states a specific verb ('Read') and a specific resource ('public Waply plan prices and terms'), which is enough to distinguish this from the calculation-oriented siblings. But it doesn't explicitly name any sibling (e.g., calculate_call_cost, list_meta_pricing_markets) that could otherwise seem related, so differentiation is implicit.

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 description gives one useful exclusion: it doesn't start a trial or purchase, so an agent won't mistake this for the subscription step. But it never says when to use this tool vs. the monthly-cost calculcators or pricing-market tools, so the agent has to infer the boundary.

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