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

Annotations only declare readOnly=false, destructive=false, openWorld=false; the description adds the material facts those hints do not convey: the score is published publicly on provecart_scoreboard, the run is scoped to the caller's own registration, and an X-API-Key header is required (integrator key or scoped key from provecart_agent_signup). The public-publication side effect is the key disclosure here. It stops short of saying whether repeated runs overwrite or append to the scoreboard entry, which is the only meaningful behavioral 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?

It is front-loaded with the action, then the mechanics, then the side effect, then auth, then the sibling contrast in a logical order with no filler sentences. It is on the dense side, with stacked parentheticals listing the planted traps, but each clause carries distinct information the agent needs. Slight length cost keeps it from a 5.

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?

For a one-parameter, non-destructive test-run tool with no output schema, the description covers everything an agent must decide before calling: what is tested, what is produced (a score), where it goes (public scoreboard), what credentials are needed, and which alternative exists for certification. Nothing material is left to inference.

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% and the single agent_id property already documents its origin ('returned by provecart_agent_register'), so the schema carries the parameter semantics. The description reinforces this with 'under your registration' and the restriction that only the registering key may run it, but adds no format or validation detail beyond what the schema already provides. Baseline 3 applies.

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 first sentence gives a specific verb and resource ('Run the ProveCart Verified Agent self-test') and immediately follows with the concrete mechanics: six fixed test carts containing planted traps, evaluated by the same verification engine as live orders. It explicitly names the sibling that is often confused with it (provecart_agent_exam_start / provecart_agent_exam_answer) and states the distinction, so an agent can pick the right tool without opening schemas.

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 an explicit when-to-use rule ('fixed-set system check') contrasted against the alternative certification path ('the live exam ... which grades your own decisions'), which is exactly the routing guidance needed among these siblings. It also states an access precondition ('Only the API key that registered the agent can run its self-test'), so an agent knows when the call will fail before making it.

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