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

Beyond the readOnlyHint annotation, the description discloses that search is case-insensitive, returns specific fields (units, coverage, verification status, license), and includes datasetMatches with fetch-on-first-call behavior. This adds meaningful context about what happens and what is returned, without contradicting annotations.

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?

The description is front-loaded with the core purpose ('Find series across ALL sources in one call') and is two sentences total. The second sentence is dense but packs essential return details and dataset behavior, justifying its length.

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 search tool with four parameters and no output schema, the description adequately covers purpose, return contents, datasetMatches semantics, and the fetch-on-first-call behavior. Combined with complete schema documentation, the agent has enough context to invoke the tool effectively.

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 is 3. The description adds value by explaining that the query parameter searches across series ids, indicator names, geographies, and dataset titles, with concrete examples, which enriches the schema's generic parameter descriptions.

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 the tool finds series across ALL sources in one call, specifying searchable fields (series ids, indicator names, geographies, dataset titles) with examples. It distinguishes itself from sibling tools like get_series and list_datasets by emphasizing cross-source search and the fastest path to a series id.

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 conveys when to use it: for cross-source search and as the fastest path from a question to an exact series id. It does not explicitly name alternatives or state when not to use it, but the context is clear enough to guide an agent.

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