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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description usefully adds that the index is Dutch/Flemish-scoped and that gaps are reported per provider type, but it says nothing about result shape or how missing entries are determined.

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?

Two sentences, front-loaded with what is returned and followed by the reason to use it. Slightly convoluted phrasing ('Which provider types a Dutch or Flemish city lacks') but no wasted content.

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 one-parameter, read-only lookup with no output schema, the description conveys both the query target and the meaning of the result. Only the concrete return shape (list vs. count) is left unstated.

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 0%, so the description must carry the load for the single 'city' parameter — and it does constrain the domain to Dutch or Flemish cities, which is real semantic guidance beyond the bare string type and length bounds.

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 resource and scope: provider types that a Dutch or Flemish city lacks in the index. An agent can tell this apart from the sibling search/stats tools, though no sibling is named explicitly.

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 second sentence hints at why the result matters ('to explain when to look online or in a nearby city'), which implies the usage context but does not state when to call this tool versus tdd_search or tdd_abroad. Usage is inferred, not directed.

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