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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so safety and repeatability are covered structurally. The description adds genuine context by calling the reputation 'black-box', signalling the values are externally computed and not directly inspectable, and by listing the facets returned. It stops short of noting whether the agent must be registered for a result or what happens on an unknown id.

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?

One sentence, front-loaded with the verb and the payload facets, with no filler or redundant phrasing. The parenthetical list is dense but earns its place by telling the agent what data to expect.

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?

Return values are covered by the output schema and the safety profile by annotations, so the description need not repeat them; the facet list plus 'black-box' framing is proportionate for a one-parameter read tool. The remaining gap is sibling disambiguation against the other reputation lookups, which is the only thing an agent still has to guess.

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 coverage is 100% with a single required string (maxLength 128), so the schema fully documents shape and constraints. The description only restates that the id refers to a 'registered agent', adding slight semantic value (the id must correspond to an existing registration) but no format or sourcing detail. Baseline 3 is appropriate when the schema does the heavy lifting.

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 specific verb+resource ('Read black-box public reputation') and enumerates the payload ('tiers, gates, track record, evidence') plus the lookup key ('by its agent id'). It is clear for an agent, though it never names the near-identical siblings (kellian_get_my_reputation, kellian_get_subject_reputation, kellian_get_counterparty_reputation), which is what keeps it from 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?

'Public reputation ... for a registered agent' implies the use case: looking up another agent rather than oneself, and the 'black-box' framing hints it is a derived/opaque score. However, there is no explicit when-to-use/when-not guidance and no routing to the batch or subject-scoped reputation siblings, so selection in this crowded namespace is left to inference.

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