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

Annotations already establish that this is read-only, idempotent, non-destructive, and open-world. The description adds behavioral clarity by specifying the exact payload fields (name, citations, court, jurisdiction, decision date, reporter location, source URL) and indicating that the full text itself is not returned. No contradiction exists between description and annotations.

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?

A single front-loaded sentence gets straight to the action and resource, with the field list in parentheses. There is no filler or repetition; every clause earns its place.

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?

For a one-parameter, read-only, idempotent lookup with no output schema, the description is complete: it identifies the input and enumerates the expected return fields. An agent can select and invoke the tool correctly without additional context.

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 100% schema coverage for the single required id parameter, the baseline is 3. The description merely repeats that the lookup is by CAP id and adds no extra format, range, or semantics beyond the schema's example and type.

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 action and resource: 'Get full metadata for a single case by its CAP id.' It enumerates the exact metadata fields returned and clarifies that the full text is only referenced by URL, which distinguishes it from sibling tools like caselaw_opinion_text, caselaw_search, and caselaw_citation_lookup.

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?

The phrase 'single case by its CAP id' gives a clear context for use: an agent should call this when it already has a CAP id and needs the case metadata record. The mention of the source URL for full text implicitly signals that full-opinion retrieval is out of scope, though no sibling tool is explicitly named and no when-not-to-use guidance is provided.

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