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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint=false and destructiveHint=false, so safety is covered. The description adds genuinely non-structural behavior: unresolved federal and sister-state reporter mentions are returned as a separate list, and the index is text-mention only rather than treatment-aware.

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 tight sentences, front-loaded with the core purpose and finishing with the most important caveat (not a citator). Nothing is repeated from the schema or 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?

Output schema exists, so return shapes need no explanation, and the description covers purpose, input forms, and caveats well. An unexplained 'limit' parameter and the absence of a named fallback sibling keep it just short of complete.

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?

With 0% schema description coverage, the description must carry the load, and it does for the required param: 'query is a cluster id, reporter cite, or case number' gives three concrete accepted forms. The optional 'limit' parameter is left unexplained, which is the only gap.

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 names a specific verb and resource — 'cases this opinion's text cites' — and states the normalization basis (Harvard reporter identifiers, Rule 22 case numbers). The directionality is explicit, which lets an agent separate it from the reverse-direction sibling cases_citing_case without opening either schema.

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?

'Text-mention index only: not a citator, not treatment, not good law' is a clear when-not statement that prevents misuse for citator-style work. It stops short of naming which sibling to use instead (e.g. case_search or cases_citing_case for reverse lookup), so it is strong but not a full routing rule.

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