device_count

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

The description signals a read-only aggregate operation via 'Get the count', which is useful since no annotations are provided. However, it does not disclose whether the optional filters narrow the count, how unit scoping and permissions behave, or what exact response shape the caller should expect. For a simple count tool this is a modest but real gap.

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 with no filler; every word earns its place. It is appropriately sized for a tool whose main behavior is simply counting devices within a unit.

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?

The description conveys the essential outcome ('count') and the schema fully documents the five parameters, including the required unit. It does not explicitly state that the response is an integer or that filters apply to the count, but these are reasonably implied. No output schema exists, yet the description is mostly sufficient for a simple aggregate tool.

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 100%, so the description does not need to restate parameter meanings. It does highlight the central 'unit' scoping, but it adds no extra semantics about how the optional filters interact with the count. Baseline 3 is appropriate because the schema carries the parameter documentation.

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 states a clear action ('Get the count') with a specific resource ('devices') and scoping ('in a unit'). The word 'count' naturally distinguishes it from siblings like device_list and device_get, which return records rather than an aggregate.

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 does not mention alternative tools or explicitly state when to choose device_count over device_list or device_get. The counting purpose is implied, but an agent must infer that this tool is for aggregate counts rather than detailed listings. This is adequate but not explicit.

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