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 covered. The description adds genuine behavioral value by disclosing what the response contains (direct and ultimate parent entity fields), which matters because there is no output schema. It does not mention error behavior for a non-owned LEI id.

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 front-loaded sentence that leads with the action and then details the returned fields. It is dense with field names, but that detail earns its place given the absence of an output schema; no filler text.

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 one-parameter, read-only lookup with full annotation coverage, the description plus schema covers nearly everything an agent needs, and the field enumeration compensates for the missing output schema. The only gap is sibling disambiguation against get_lei_record and list_my_leis.

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 schema already explains that leiId is a GUID obtained from list_my_leis and is not the 20-character LEI number. The description adds nothing beyond that, 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 gives a specific verb and resource ('Returns one of the user's LEIs with all application details') and enumerates the parent entity data returned. It is clear on its own, but it does not distinguish itself from the sibling get_lei_record or explain its relationship to list_my_leis.

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 explicit when-to-use guidance: nothing says to call this after list_my_leis, or why an agent would pick this over get_lei_record. The only routing hint ('from list_my_leis') lives in the schema's parameter description, not in the tool description itself.

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