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

Annotations already declare the safe read-only, idempotent profile, so the bar is lower, but the description adds a genuine behavioral fact: it requires a caller-supplied ReliefWeb appname in _apiKey. With no output schema present, naming the per-disaster fields (GLIDE, type, countries, date, status) also informs what comes back. It does not disclose pagination limits or rate behavior, keeping it out of the top band.

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 front-loaded sentences: identity/contents first, then authority/use, then filtering and the auth requirement. Every sentence carries information, though the opening enumeration of fields is slightly dense and could be trimmed.

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 a 7-param, zero-required read tool with full schema coverage, annotations, and no output schema, the description covers what the tool is, when it is authoritative, how to filter, and the auth requirement. It could be stronger by clarifying the relationship to reliefweb_reports and basic paging behavior, but the essentials are present.

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 every parameter is already documented in the schema, giving a baseline of 3. The description restates the filter axes (country, status, disaster type, search by name) but adds no syntax or format detail beyond what the schema already conveys.

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 (the ReliefWeb disaster register) and its contents (GLIDE numbers, disaster type, affected countries, event date, status lifecycle), making the verb+resource unmistakable. It implicitly separates itself from sibling reliefweb_report/reliefweb_reports, which concern reports rather than the disaster register itself. An agent can distinguish what this returns without opening a schema.

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 clear use context: "AUTHORITATIVE for 'which humanitarian emergencies are active right now' and for resolving a crisis to the identifier the rest of the humanitarian system uses." It also names the filter dimensions for narrowing. It stops short of explicitly naming sibling tools (reliefweb_reports) as the alternative for the report-oriented question, so it is clear context rather than full when/when-not routing.

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