Count Features

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

The readOnlyHint annotation already indicates this is a read-only operation. The description adds that it works on the active map but does not disclose additional behavioral traits such as performance implications or that it depends on the layer being available.

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 a single, front-loaded sentence that is concise. However, it sacrifices necessary detail about the parameter, so it is not optimally structured for usability.

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?

Given the 0% schema description coverage, the description should compensate by explaining the 'layer' parameter, but it does not. While an output schema exists, the description lacks critical context for using the 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?

The only parameter 'layer' is a string with no description in the schema (0% coverage). The description does not explain what values the 'layer' parameter accepts or how to specify it, such as layer name or ID.

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 the tool counts the number of features in a layer of the active map. It uses a specific verb ('count') and resource ('features'), and it distinguishes itself from sibling tools like 'get_layer_features' and 'describe_data'.

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 description implies the tool is used when you need a count of features, but it does not provide explicit guidance on when to use it versus alternatives, nor does it mention any prerequisites or exclusions.

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