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

With no annotations provided, the description carries the full burden, and it does disclose meaningful behavior: no server computation, an interactive tap-when-green loop, and a millisecond result. It omits secondary traits such as whether the locale affects the card UI or whether results are persisted, keeping it short of a 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?

Two tight sentences, zero filler, and the core behavior and output are front-loaded in the first clause. Every phrase earns its place.

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?

There is no output schema and only one optional parameter, so the description's coverage of the interaction and the millisecond result is nearly sufficient. The only real gap is the unexplained locale parameter, which is minor for a zero-required-parameter UI card.

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 single locale parameter has 0% schema description coverage and is never mentioned in the description, so the agent gets no explanation of what the en/zh enum actually controls. The schema's enum and default are self-explanatory enough to avoid a 1, but the description adds nothing here.

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 names a specific artifact (an interactive reaction-time test card) and states exactly what it measures (milliseconds), so an agent immediately knows what the tool produces. It does not, however, differentiate itself from similar interactive-card siblings like typing-test or quiz, so it lands just short of a 5.

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?

Usage is only implied: the tool is for running a client-side reaction test. There is no statement of when to prefer it over siblings such as typing-test, nor any exclusions or preconditions, so the agent must infer the context.

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