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

The description adds significant context beyond the annotations: payment requirement with 402 behavior, that optional attributes remain null unless certified, and the output shape. It confirms read-only/idempotent nature without contradicting the annotations, and enriches them with operational details.

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 tightly organized: what it does, how to use it, payment, and limitations. Each sentence earns its place with no filler. Front-loaded purpose; payment and behavioral disclaimers are kept separate and concise.

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 lookup tool with 5 optional parameters and no output schema, the description covers the essential context: search criteria, payment, return shape, and unsupported attributes. It gives enough for an agent to decide when to call and what to expect without needing explicit output schema.

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%, so baseline is 3. The description adds meaning by explaining that filters like 'rail_connected' are not asserted unless separately published, which clarifies the actual effect of the parameter. This is beyond the bare 'Rail connectivity filter' schema description, justifying a 4.

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 opens with a specific verb and resource: 'Search India's current official ICEGATE ICD/CFS directory' and clarifies the search dimensions (code, name, type). This clearly distinguishes it from the sibling tools like shippingrates_inland_search or shippingrates_cfs_tariffs.

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?

It explicitly states 'Use this to resolve an official ICEGATE ICD/CFS code or facility name,' giving a clear when-to-use. It also warns about unsupported attributes (GPS, rail, operator, capacity), implying when not to use this tool for such data. However, it does not name specific alternatives, so it stops short of a 5.

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