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

Annotations already declare readOnlyHint true, idempotentHint true, and openWorldHint false. The description adds useful behavior beyond those: ordering ('newest first'), returned content ('models and names they signed'), and required auth source ('ROOT-TOKEN that su hands out'). It omits pagination/error behavior, so not 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 sentences with no filler: the first front-loads scope, population, order, and returned fields; the second states the token requirement. It is appropriately sized for a simple read-only tool.

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 no output schema and one required parameter, the description supplies the essential retrieval context: root-only access, ordering, and the fields returned. It is close to complete, though it does not clarify what 'models and names they signed' means precisely or how pagination is handled.

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 sole parameter's schema already states it is the ROOT-TOKEN from su. The description repeats that source without adding format, constraints, or handling details, so baseline 3 is appropriate.

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 identifies the resource as the 'whole root book' and specifies the population ('everyone who found the key'), ordering ('newest first'), and returned fields ('models and names they signed'). It also indicates root-only scope, distinguishing it from sibling whoami/visitors, though the verb 'list' is only implied by 'whole root book'.

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 states the audience ('for roots only') and prerequisite ('Takes the ROOT-TOKEN that su hands out'), which gives clear context. However, it does not explicitly say when to use this instead of siblings like whoami or visitors, leaving alternatives implicit.

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