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

Annotations already declare read-only, idempotent, and non-destructive behavior, so the description correctly spends its words on the non-obvious trait: that results are raw text mentions, not validated citations or treatment. It does not describe result ordering or how pagination behaves, which would have made this 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?

Three short sentences, front-loaded with the core purpose, then input formats, then the critical caveat about what the index is not. No filler and nothing redundant with the annotations.

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 an output schema present, return-value detail is unnecessary, and the description covers purpose, query syntax, court values, and the text-mention caveat. The remaining gap is the temporal window parameters (after/before) and limit, which an agent would need to call this confidently.

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 burden; it usefully explains the three accepted query formats and the three court values, which the schema does not. However, after, before, and limit are never explained, leaving three of five parameters with no documented meaning.

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 resource with a precise relation: 'Opinions whose text cites this case.' The direction (citing, not cited-in) is explicit, which cleanly separates it from the sibling cases_cited_in and from cases_citing_court.

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?

Gives clear negative guidance — 'Text-mention index only: not a citator, not treatment, not good law' — which tells the agent when results are unsuitable. It stops short of naming a sibling to use instead for citator-style or reverse-direction needs, so the alternative routing is implied rather than stated.

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