Check desk and mousepad fit

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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so the safety profile is covered. The description adds genuine behavioral context by disclosing the geometry model (keyboard is positioned with its B key in front of the screen centre) and enumerating what is reported back, including the 360-degree turn feasibility test. It stops short of stating units or edge-case behavior, so not a full 5.

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?

Four sentences, front-loaded with the core purpose and then the mechanics, with no filler. The final compare-across-keyboards sentence is slightly redundant given the presence of a compare_keyboards sibling, but it is short and informative.

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?

With seven parameters, no output schema, and no nested objects, the description does the necessary work of explaining the returned values so the agent knows what comes back. It omits output units and the default/fallback behavior for optional inputs, which are minor remaining gaps.

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 all seven parameters are already documented, which sets the baseline at 3. The description re-explains keyboard_offset_cm and cm/360 in prose but adds no new syntax, format, or constraint information beyond the schema.

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 verb and resource ('Check whether a keyboard and mousepad fit side by side on a desk') and goes further by naming the exact inputs that drive the computation (keyboard_offset_cm, cm/360). An agent can distinguish this geometric-fitting tool from dimension-lookup siblings like get_keyboard_dimensions without opening a schema.

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 closing sentence gives an implied use case ('compare several keyboards at once to see which one leaves the most room'), which is real context. However, it never names or excludes the obvious alternatives in the sibling list (compare_keyboards, get_keyboard_dimensions), and there is no when-not guidance, so the agent must infer the boundary itself.

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