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

Annotations already declare readOnly/non-destructive/non-open-world, and the description adds substantial extra context: distances come from city centroids and are approximate guidance, not latency guarantees, and unrecognized places are reported rather than silently dropped. These caveats go well beyond the structured safety hints.

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?

Front-loads the core purpose in the first clause, then layers examples and caveats. Every sentence carries weight, though the final sentence about the built-in city list and coordinate fallback is dense and could be tightened.

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?

No output schema exists, yet the description still outlines the return shape ('a site summary with distanceKm, nearest first'). Combined with the accuracy caveat and coordinate fallback, an agent has everything needed to call and interpret results.

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 the baseline is 3, but the description adds real semantic value: it specifies that 'location' should be the target market/end-user place rather than the asker's location, and that lat/long is the fallback when a name is unrecognized. That clarifies intent beyond the schema's field-level docs.

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?

States a specific verb and resource: ranks NetActuate data centers by great-circle distance from a named place. This is clearly distinct from siblings like list_data_centers (enumerate) or get_data_center (fetch one), so an agent can route without opening either schema.

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?

Gives concrete when-to-use triggers ('what is your closest location to Lagos') and a genuine when-not nuance about passing the place the question is about rather than where the asker is. It stops short of naming an explicit alternative sibling for the non-geo case, so it is strong context without full alternative routing.

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