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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, destructiveHint=false. The description adds useful context beyond these: it notes the tool returns 'the case, the court, the date and the CELEX id' and clarifies the search scope ('by subject'). It does not contradict the annotations and provides meaningful behavioral context for a read-only search operation.

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?

The description is concise and front-loaded with the key purpose ('Search EU COURT JUDGMENTS'). It uses 3-4 sentences with no filler, includes concrete example queries, and clearly states an alternative tool. Every sentence adds value, and the structure leads with the most important information.

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?

The description is complete for a search tool: it explains what it returns (case, court, date, CELEX id), provides usage examples, and differentiates from search_legislation. However, it says 'by subject' while the schema states query matches 'Words appearing in the case title'—this slight mismatch could mislead an agent into expecting semantic subject search rather than title keyword search. Given no output schema, the description covers return fields adequately but this nuance is a minor gap.

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 100%, so the baseline is 3. The description does not add parameter-specific details beyond what the schema already provides; it mentions the court types (CJEU and General Court) and example queries, but these are also implied by the schema. The description does not compensate further or introduce new parameter 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?

The description clearly states a specific action: 'Search EU COURT JUDGMENTS — the case law of the Court of Justice (CJEU) and the General Court — by subject.' It identifies the resource (EU court judgments) and distinguishes itself from search_legislation, which covers Regulations and Directives. This is a precise, non-tautological statement.

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 description provides explicit guidance on when to use this tool: 'Use for "what has the CJEU said about data protection"...' It also contrasts with an alternative: 'This is case law; search_legislation covers the Regulations and Directives themselves.' This satisfies both 'when' and 'when-not' criteria.

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