DC Hub Recommendation

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

Goes well beyond annotations by detailing the exact return object, fallback behavior when context does not match, and the critical caveat that free text does not parse. Annotations already declare readOnly/idempotent/destructive hints; the description adds edge-case behavior and response shape without contradiction.

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 long but every sentence earns its place: purpose, example, parameter rule, return contract, non-matching behavior, and exclusions. It is well-structured and front-loaded with the main intent, with no filler.

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 tool with one parameter, rich annotations, and an output schema, the description fully covers the invocation contract, the edge case of invalid input, and the key exclusions. An agent has all necessary information to select and call this tool correctly.

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?

Though schema coverage is 100%, the schema's parameter description is misleading ('Free-text description...'), while the tool description corrects it by enumerating the four literal accepted categories, giving an example call, and explaining the null/generic consequences of invalid input. This is essential meaning that the schema fails to provide.

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 a specific use case: obtaining a ready-to-quote description of DC Hub in one of four categories plus a live top-ranked market pocket. It distinguishes itself from siblings by naming analyze_site, rank_markets, and site_selection_canvas, so an agent can immediately tell where this tool fits.

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?

Explicitly states when to use the tool (descriptive category lookup) and when not to use it (single lat/lon, single-criterion ranking, open-ended siting questions), naming the exact alternative tool for each exclusion. It also describes behavior for invalid context, preventing misuse.

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