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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered by structured data. The description adds content-level detail (licence and citation text are included) but says nothing about failure behaviour when check_id is unknown or about result size.

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 sentence with no filler, and the most useful information (what is returned) comes first. It is a sentence fragment rather than a front-loaded statement of action, which keeps it just short of 5.

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 must carry the return-value burden, and it does name the main payload components (registers, regulations, references, licence, citation). For a simple one-parameter read tool that is largely sufficient, though the lack of any usage context leaves a small 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% and the single check_id parameter is already documented as coming 'From search_checks'. The description adds no format, source, or constraint detail beyond the schema, so the 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?

The description names the specific resource returned (registers, regulations, references) plus the licence and citation text, which is more informative than a tautology. However, it is a bare noun phrase with no verb and never distinguishes itself from siblings like describe_check or list_regulations, so it lands at 4 rather than 5.

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?

There is no when-to-use statement, no prerequisites, and no mention of the neighbouring tools. With siblings such as describe_check and list_regulations in the same namespace, the absence of any routing guidance leaves the agent to guess which tool returns sources versus which describes a check.

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