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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=false and destructiveHint=false, so the safety profile is covered. The description adds genuinely useful non-annotation context: the return shape {id, title, url} and the cross-tool contract that id is the cite anchor fetch accepts, which tells the agent this result is a handoff point. It stops short of noting limits like result counts or coverage gaps in the held corpus.

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: what it searches, what it returns and the id contract, then the alternative. The routing sentence is front-loaded in a position where it prevents a wrong tool choice, and no sentence is filler.

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 tool is a single-parameter read whose annotations carry the safety profile and whose output schema carries the return values; the description therefore only needs purpose, handoff semantics and sibling routing, all of which are present. Nothing an agent needs to call this correctly is missing.

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?

Only one parameter and schema description coverage is 100%, so the schema already documents the query field with examples. The description reinforces the topical domain ('SCA, open banking and safeguarding') but adds no syntax, quoting or citation-format guidance beyond what the schema provides. Baseline 3 applies.

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 and resource ('find EU payments legislation') plus the topical scope (SCA, open banking, safeguarding) and the instrument corpus (PSD2, RTS-SCA, PSD3/PSR). It also distinguishes itself from the sibling search_legislation by calling this the 'simple' variant, so an agent can pick correctly 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?

Explicit routing: use this for a simple top-hits lookup, use search_legislation when filters, snippets, scores or paging are needed. The condition that selects the alternative is stated outright, with no inference required.

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