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

Annotations already declare readOnlyHint=true, destructiveHint=false, idempotentHint=true, and openWorldHint=true. The description adds valuable behavioral context beyond annotations: 'Uncertified families remain empty and legacy rows are never used as a fallback' clarifies data coverage limits, and 'FREE — no payment required' discloses cost. It also outlines the return structure, though it does not detail pagination or rate limits.

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 well-structured and information-dense, covering purpose, match targets, behavioral constraints, cost, return format, and related tools in six sentences. There is minor redundancy ('FREE — no payment required' repeats the word free), but no wasted detail.

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?

The description is remarkably complete for a simple search tool. It explains the data scope, limitations, cost, return shape, and alternative tools. Despite lacking an output schema, it explicitly lists the return object structure. Sibling tools are numerous, but the description helps disambiguate by referencing the most relevant alternatives.

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% as the single parameter 'keyword' has a description with examples. The description adds semantic meaning by explaining what the keyword matches (certified port codes/names, reviewed carrier identities, published transit services, local-charge names/carriers), which helps the agent choose effective search terms.

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 clearly states the tool's function: 'Search current customer-published ShippingRates datasets by keyword.' It specifies the resource (customer-published ShippingRates datasets), the action (search), and the scope (matching certified port codes/names, reviewed carrier identities, published transit services, and local-charge names/carriers). It also distinguishes from siblings by explicitly naming related tools for structured lookup.

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 provides explicit usage guidance by naming alternatives: 'Use shippingrates_port for structured port lookup by UN/LOCODE, shippingrates_lines for full carrier listing.' It also includes a when-not-to-use signal: 'Uncertified families remain empty and legacy rows are never used as a fallback,' implying this tool is only suitable for certified/published data.

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