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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, covering the safety profile. The description adds valuable behavioral context beyond annotations: it states the operation is 'free, no credits', which is a cost behavior, and lists the specific data returned (checksums, citations). It does not contradict annotations and provides meaningful supplemental disclosure.

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 with no fluff: the first states the primary function and cost, the second details the output contents. The most important information is front-loaded, and every phrase earns its place. Structure is clean and easily scannable.

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?

With a single optional parameter, no output schema, and read-only annotations, the description adequately covers what an agent needs: what the tool does, cost, and what data will be returned. It does not describe pagination or error cases, but for a simple metadata-listing tool this is a minor gap. The presence of a broad sibling list does not add complexity that this description fails to address.

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 100%, so the schema already fully documents the single optional engineId parameter, including example values and purpose. The description does not add any extra meaning about the parameter—it focuses on the tool's overall output. With the schema carrying the weight, a baseline of 3 is appropriate.

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 states a specific verb ('Lists') and resource ('official rate tables each calculator uses'), making the tool's purpose immediately clear. It also differentiates this from sibling calculator tools by framing it as a metadata/status tool, not a computation tool. The mention of concrete contents (hash checksums, citations) further sharpens the scope.

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 implies usage ('Lists the official rate tables each calculator uses') but does not explicitly state when to choose this over sibling calculators or when not to use it. There is no mention of alternatives or a decision context, leaving the agent to infer that this is for inspecting rate tables before running calculations. This is adequate but lacks explicit guidance.

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