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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), yet the description adds substantial non-obvious behavior: case-insensitive matching, exact-name ranking over partial title matches, envelope shape, a currency/commencement block that flags expired or not-yet-applying law, and the ambiguous/disambiguation/preferred/alternatives fields. It also declares "Requires no credentials," which no annotation supplies.

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?

Purpose and the resolve-id-before-other-tools instruction are front-loaded in the first and last sentences, and each middle sentence carries distinct return-shape information that is not stated elsewhere. The single dense paragraph is longer than strictly necessary and would scan better as bullets, costing it a point.

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 no output schema, the description carries the full burden of describing the return value and does so: the matches array contents, the currency block, and the ambiguity handling fields. Combined with the credential note and the pre-call routing advice, an agent has everything needed to invoke and interpret this tool correctly.

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, but the description extends the query parameter's semantics beyond the schema by admitting practitioner common names ('Market Abuse Regulation', 'MLRs', 'UK GDPR') and Lex-Ray ids, which the schema does not mention. Limit is left entirely to the schema, which documents it adequately.

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 (Find) and resource (EU and UK legislation) and enumerates the accepted query forms — keyword, acronym, common name, CELEX ID, Lex-Ray id — which an agent cannot infer from the name alone. It also implicitly separates itself from get_legislation by framing the task as resolving a name to an id, so the sibling boundary is legible.

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?

Explicitly instructs "Use this to resolve a name to an id before calling the other tools," giving clear when-to-use context, and adds tie-breaking advice (choose by jurisdiction and title rather than taking the first). It stops short of naming get_legislation or stating a when-not condition, so it is strong but not fully routing-complete.

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