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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the bar is lower. The description adds real behavioral context beyond them: AND-combination of filters, browse-when-empty semantics, and — with no output schema — the no-match `suggestions` field that names which filter to drop and how many items that would surface.

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, front-loaded with 'The main discovery tool' and the corpus size, then routing to the sibling, then the edge-case response behavior. No filler or restated name/title.

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 16-param, zero-required search tool with no output schema and annotations covering safety, the description covers purpose, filter interaction, fallback behavior, and the detail-lookup alternative. Only minor gaps remain, such as pagination/result-shape expectations, and limit/offset defaults are already documented in the schema.

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 coverage is 94%, so parameters are largely self-documenting and the baseline would be 3. The description adds cross-parameter semantics the schema cannot show: that all filters combine with AND and that omitting every filter is a valid browse mode, which meaningfully changes how the 16 params should be used together.

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 verb and resource ('search the ~4,000 research items ... digitised artefacts — images, texts, audio, video') and scopes it to all Africa Multiple project collections. It also distinguishes itself from the sibling get_research_item, which returns one item's full detail.

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 concrete usage patterns ('items about subject X', 'items from location Y'), states that filters are optional and AND-combined and that omitting them browses everything, and names the alternative get_research_item. It does not, however, contrast itself with the generic `search` sibling, so routing among the search* family is still partly inferred.

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