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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds one genuine behavioral constraint not present in the schema — that limit caps at 25 — which is valuable, but it says nothing about matching behavior, paging, or empty-result handling. An output schema exists, so return-shape disclosure is not required.

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?

Two compact clauses, the core operation front-loaded and the numeric cap trailing. No filler, no restatement of the tool name, and nothing that could be cut without losing signal.

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 two-parameter keyword lookup with a declared output schema and annotations covering safety, the definition supplies what is needed to call it: the input is a keyword, the cap is 25. The remaining gap is routing relative to sibling interest tools, which is scored under usage guidelines rather than completeness here.

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 0%, so the description must carry the parameter burden. It does partially: 'by keyword' tells the agent what query means and 'limit up to 25' supplies a maximum bound the schema omits entirely. However, the default limit and match semantics (substring vs exact) are missing, leaving half the parameter meaning to inference.

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 states a specific verb (Search), resource (Meta interest IDs), and method (by keyword), so an agent knows exactly what it returns. It stops short of naming a distinguishing boundary against neighbors such as targeting_search or interests_list, but the operation itself is unambiguous.

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?

There is no explicit when-to-use or when-not-to-use guidance, and no sibling is named as an alternative even though interests_list, interests_get, and targeting_search all overlap in the interest domain. The only usable signal is the implicit 'search by keyword when you don't have an ID', which the agent has to infer.

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