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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered by structured data. The description's only added behavioral value is the dependency relationship with validate_data; it says nothing about the shape of the returned list, ordering, or whether versions are grouped per standard. With annotations carrying the burden, a 3 is appropriate.

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 the usage trigger front-loaded and no filler. Every clause contributes either the trigger or the dependency on validate_data.

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 zero-parameter, read-only discovery tool whose annotations already state the safety and idempotency profile, this is sufficient: the agent knows what it returns conceptually (standards plus versions), why to call it, and in what order relative to validate_data. No output schema exists, but the description conveys the content of the result well enough to act on.

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?

The tool takes zero parameters, so the schema leaves nothing to interpret and the baseline of 4 applies. The description correctly implies the call is unfiltered and complete rather than scoped by any argument.

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 concrete resource: sustainability data standards and their versions that validate_data can check. It also distinguishes the tool from the large sibling set by tying it explicitly to validate_data, so an agent can tell it apart from validation or semantics tools. The verb is slightly implicit ("see which ...") rather than a direct "list," which keeps it just below a 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?

It gives an explicit trigger condition ("Use this when you need to see which standards ... can check") and a sequencing rule ("before calling it" referring to validate_data), which is the key routing decision an agent faces. It stops short of stating when not to use it or what to do if the standard is already known.

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