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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered; the description adds the ranking signal (citation counts) and the default limit of 20, which are behavioral facts not in the annotations. It omits anything about ordering ties or result shape, but an output schema exists to cover returns.

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?

Front-loaded purpose sentence, then ranking semantics, then a compact Args block. The per-parameter type labels ('Domain slug', 'Optional court filter') partially restate the schema, but the parenthetical examples earn their space.

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?

A read-only, three-parameter ranked-query tool with an output schema; the description covers purpose, ranking basis, and all three arguments. Only edge-case behavior (empty domain, invalid court code, pagination beyond limit) is unaddressed.

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 0%, so the description carries the full burden and mostly does: domain_slug gets two concrete examples, court gets example codes ('UKSC', 'EWCA-Civil'), and limit states its default. What is missing is any hint of valid slug formats or what an invalid court code does.

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 ('Get the most-cited authorities in a legal domain') and adds the ranking basis ('Ranked by how many other cases cite them'), which distinguishes it from generic search siblings. It does not name a specific alternative like search_cases or get_related_authorities, so differentiation is inferred rather than stated.

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?

'Use this to find the leading cases, statutes, or rules in an area of law' gives a positive use case but no exclusion or comparison against search_cases, get_related_authorities, or browse_taxonomy. An agent knows roughly when it applies but not when to prefer a sibling.

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