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

While annotations already declare safe read-only behavior, the description adds meaningful behavioral context: search scope (certified/reviewed/published data), the no-fallback policy for uncertified/legacy data, that it is free, and the return structure. This goes well beyond the annotations. No contradiction with annotations.

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: opens with a clear action sentence, then elaborates on scope and exclusions, followed by return format and alternative tools. Every sentence earns its place; no redundancy or filler. It is appropriately concise for the information it conveys.

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 covers purpose, search scope, exclusions, return format, and alternative tools. For a single-parameter keyword search, this is thorough. The return structure is explicitly given, so the agent knows what to expect even without an output schema. The tool's complexity is fully addressed.

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?

The schema already provides complete parameter documentation (100% coverage) with examples. The description further enriches semantics by enumerating the entity categories the keyword can match (port codes/names, carrier identities, transit services, local charges), giving the agent a clearer model of valid inputs. This adds value beyond the schema.

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 uses a specific verb ('Search') and resource ('current customer-published ShippingRates datasets'), and further distinguishes itself by listing matched entity types (port codes/names, carrier identities, transit services, local-charge names/carriers) and explicitly contrasting with sibling tools (shippingrates_port, shippingrates_lines). This makes the tool's unique purpose clear.

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 explicitly names alternatives (shippingrates_port for structured port lookup by UN/LOCODE, shippingrates_lines for full carrier listing) and explains when they are preferable. It also states exclusionary behaviors ('Uncertified families remain empty and legacy rows are never used as a fallback'), providing clear when-to-use vs. when-not-to-use guidance.

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