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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds useful context beyond annotations: licensing (CC BY-NC-SA 3.0 IGO), no-auth requirement, and 'unlimited free' quota, which helps an agent understand constraints without needing to inspect the API.

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, zero filler. The first sentence states purpose and scope, the second provides the key follow-up instruction, and the third covers licensing/auth. Front-loaded with the most important information.

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?

The description is complete for a simple, read-only search tool. Output schema covers return structure; annotations cover safety; description adds the downstream usage hint and licensing. The only flaw is the tool-name typo, which slightly detracts but doesn't leave the agent without necessary context.

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% — both parameters have clear descriptions including defaults and examples. The tool description adds no additional parameter-level meaning beyond what the schema already provides. Baseline of 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 clearly states a specific verb ('Search'), resource ('WHO Global Health Observatory catalog of 3,000+ health indicators'), and output ('indicator codes, full names, and definitions'), naming concrete example topics. It also differentiates itself from the data-fetching sibling by directing users to use the returned indicator_code with who.indicator_data for actual values.

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 description gives useful context: search by keyword, then use the returned code with who.indicator_data to fetch values. However, the cross-reference is to 'who.indicator_data' whereas the actual sibling tool is 'who.health.indicator_data' — a minor but potentially misleading error. It also doesn't explicitly distinguish when to use this versus the sibling 'who.health.indicators'.

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