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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), so the description's marginal contribution is the auth requirement — a caller-supplied ReliefWeb appname in _apiKey — which is operationally critical. It also discloses the returned field set and warns that include_body yields long text, both beyond what the annotations state.

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 dense sentences: scope/corpus, then authoritative-use framing, then filters, returns and auth. Front-loaded and waste-free, though the publisher-count detail ('~4,000') is flavor rather than decision-relevant.

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 an 11-parameter, no-required-args search tool with a 100%-covered schema and no output schema, the description supplies everything an agent needs: auth mechanism, filter axes, return fields, and the include_body tradeoff. Nothing material is missing.

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% with an examples block, so every parameter is already documented with examples. The description's re-listing of filter dimensions (country, disaster, disaster type, source, theme, format, date) and free-text search over title/body adds no syntax or semantics beyond the schema, 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?

States a specific resource (ReliefWeb-published reports) with an explicit scope (humanitarian situation reports, needs assessments, appeals, analyses, press releases from ~4,000 publishers) and a clear positioning versus news coverage. The distinction from siblings reliefweb_report (single document) and reliefweb_disasters is inferable from the plural/collection framing.

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 a concrete selection criterion — 'AUTHORITATIVE for what do humanitarian responders say is happening in <country or crisis>' — which tells the agent when this corpus beats generic news search. It stops short of naming reliefweb_report or reliefweb_disasters as the alternatives for single-document or disaster-event lookups.

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