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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds the useful multi-match behavior ('they are listed') and the accepted identifier forms, but says nothing about not-found handling, result size, or auth needs, so added value is moderate.

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 core action and resource in the first clause, then a compact enumeration of return fields; no filler sentences. The field list is slightly long but every item is informative for a caller.

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 compensates by naming the returned fields, and it clarifies the accepted identifier forms for the single required parameter. The only real gap is the no-match case, which is left unstated for a lookup tool.

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, but the description genuinely extends the allowed value space beyond the schema's single example: it accepts a former name or a page slug, not just a current display name. That is real semantic information the schema does not convey.

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+resource ('One Nigerian mutual fund by name') and enumerates the returned fields (manager, category, currency, returns, filing start, page), so an agent knows exactly what it gets. It implicitly separates itself from the plural sibling get_mutual_funds by emphasizing 'One', but never names that alternative explicitly.

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?

Gives input flexibility (current or former name, or page slug) and a behavioral rule for ambiguous names ('if the name matches several funds, they are listed'), which implies usage. However, it never says when to prefer this over get_mutual_funds or the league table, and gives no exclusions.

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