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

Annotations already establish that this is a read-only, idempotent, non-destructive, closed-world lookup. The description adds useful behavior beyond annotations: it names the returned citation fields and states that an unknown id returns the three nearest ids instead of a guess. It does not clarify what happens if neither id nor query is supplied.

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 three tight sentences: the first frames the use case, the second states what is returned, and the third explains the unknown-id fallback. It is front-loaded and every sentence adds value.

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 an output schema, rich annotations, and 100% parameter description coverage, the description is largely complete for invocation. The remaining gap is that it does not specify the relationship between the optional id and query parameters or the behavior when neither is provided.

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 coverage is 100%, so the baseline is 3 because the schema already documents id, query, and context. The description adds meaning beyond the schema by explaining the unknown-id fallback behavior, though it still does not clarify whether id and query are alternatives or what happens when both are omitted.

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 uses a specific verb and resource: it returns an ELC figure from the Data Points registry along with citation id, source, and verification date. It does not explicitly differentiate itself from siblings such as benchmark_leadership_ratio, so it falls short of 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?

The description implies its use case by framing it as answering 'where did that number come from?' and explains the unknown-id fallback. However, it gives no explicit guidance on when to choose this tool over sibling tools or when to use id versus query.

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