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

The description adds an important non-obvious requirement: a UCDP API access token passed as _apiKey, plus temporal coverage (1989 to latest release) and the best/low/high death estimate fields. Since annotations already declare the operation read-only and idempotent, the description's additional auth and data-scope context earns it above baseline.

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 sentences plus one example, front-loaded with the core purpose and followed by the crucial auth note. There is no filler, and the example is compact enough to serve as a usage template.

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 8 parameters and no output schema, the description covers the essential invocation context: data source, filters, auth, return fields, and a complete example. The main omission is ordering/sorting behavior for queries like 'deadliest events', and it does not mention pagination beyond what the schema already documents.

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 descriptions cover all 8 parameters, so the description does not need to document each parameter. The inline example reinforces the use of country/start/end/limit/_apiKey, but it adds little semantic detail beyond the schema's own field descriptions, so baseline 3 is appropriate.

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 'Answers' as the operative verb and clearly scopes the tool to georeferenced UCDP GED events filtered by country and date range, with concrete example queries. This distinguishes it from ucdp_countries and ucdp_conflicts at a glance, though it does not explicitly contrast with ucdp_recent_events or ucdp_fatalities_summary.

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 examples ('list the deadliest events in Sudan in 2024', 'battles in Donetsk in March 2023') give an agent a clear sense of when to invoke this tool. It does not name sibling alternatives or state when not to use it, so it stops short of full exclusion guidance.

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