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 real value beyond that: the return payload shape (20-character code, legal name, status, legal address, jurisdiction), the lack of an API key requirement, and the data source domain and coverage scale.

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?

Front-loaded with the action sentence, then scannable trigger bullets. The regulatory/coverage lines ('MiFID II, EMIR, Dodd-Frank', '2M+ legal entities') are contextual flavor rather than invocation guidance, but they are brief and do not obstruct selection.

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 annotations covering safety, an output schema covering return values, and the description naming the source and returned fields, an agent has enough to call this correctly. The remaining gap is that the description says nothing about the odd internal parameters present in the schema, leaving ambiguity about whether they should be populated.

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 description only mentions the 'by entity name' input; the schema's own property descriptions (name examples, limit default 10, ISO country codes) already carry the operational detail, so a baseline 3 is warranted. It does not clarify the extraneous plumbing parameters in the schema (mcp_prompt_id, wholesaler_ids, source_resource_id, exclude_fillers), which are unrelated to LEI search and could confuse an agent about whether they are required.

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: search the GLEIF database for Legal Entity Identifiers by entity name, and names the exact fields returned. It also explicitly differentiates from the sibling GetLEIDetail by assigning parent/subsidiary lookups there.

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?

A dedicated 'Use this tool when' block lists four concrete triggering scenarios (need an LEI for an institution/fund, verify legal registration, cross-reference EDGAR entities, parent/subsidiary via GetLEIDetail). The alternative tool is named with the condition that selects it.

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