count_features

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

With no annotations, the description carries the behavioral burden. It explicitly says no rows are pulled, that it is cheap, and that it works on any layer. This covers the key behavioral traits for a count operation, though it does not mention error conditions or exact return format.

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?

Three short sentences, each earning its place: the action, the use case, and the scope. Front-loaded with the core behavior and devoid of fluff.

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?

Despite a strong purpose statement, the definition leaves critical calling details unspecified: how to identify a layer among three possible identifiers, whether any are required or prioritized, and what the return value looks like. With no annotations and no output schema, these gaps make the tool incomplete for an agent to reliably call.

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 description coverage is 0%, so the description must compensate for the four parameters. It clarifies that 'where' is a filtering clause and that any layer can be used, but it does not explain how to choose among layer_id, layer_key, or service_path, nor does it define the where-clause syntax beyond the default 1=1.

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 ('Count') and resource ('features matching a where clause'), and immediately distinguishes itself from row-returning tools by stating 'without pulling the rows.' This makes it clearly distinguishable from siblings like query_layer.

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 gives clear when-to-use guidance: 'Cheap way to answer how many X or to size a query before fetching.' This implies the alternative is fetching rows, but it does not explicitly name a sibling tool or state when not to use it.

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