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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint=false, so the safety profile is covered. The description adds useful counting semantics for the country filter, but says nothing about ordering direction, pagination, or what the ranked payload contains beyond the implied count.

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?

Three tight sentences with the ranking definition front-loaded, followed by default and filter semantics. No filler, though the country format restatement is slightly redundant with the schema.

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 five optional parameters, no required fields and no output schema, the description covers what is ranked, the default category, and the precise effect of the country filter. Remaining parameters are fully documented in the schema.

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%, so the baseline applies. The description restates the country slug/ISO acceptance and the equity default, which largely duplicates the schema rather than adding new meaning; from/to and limit are left entirely to the schema.

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 opens with a specific verb and resource: investors ranked by the number of approved rounds they appear in. That is unambiguous and distinct from search_funds or get_investor_scorecard, though it never names a sibling to contrast against.

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?

Usage is implied by the ranking framing and by the note that category defaults to equity, but there is no explicit statement of when to prefer this over get_investor_scorecard or search_funds, and no exclusions. The 'use list_fund_closes' routing exists only in the schema's category field, not in the description.

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