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

The annotations already establish read-only, idempotent, non-destructive behavior. The description adds meaningful context with 'public agent registry' and especially 'Preview data only', indicating that results are partial rather than comprehensive records. This is useful behavioral information beyond the 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 a single front-loaded sentence plus a short clarifying sentence. Every word earns its place, and there is no redundancy or filler.

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 simple two-parameter tool with an output schema, required-param count of zero, and supportive annotations, the description is complete. It communicates scope, safety, and the preview nature of the results without needing extensive elaboration.

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?

The schema already documents 'capability' with a useful description and 'protocol' with a self-explanatory enum and default. The description confirms both parameters ('by capability and protocol') but adds no additional formatting or semantic detail beyond the schema. At 50% schema coverage, this is adequate but not compensatory.

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 uses a specific verb ('Search'), identifies the resource ('public agent registry'), and states the search dimensions ('by capability and protocol'). This clearly distinguishes it from the sibling tools, which concern query plans, growth metrics, and Niulai info.

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 provides clear context for when to use the tool: searching the public agent registry by capability and/or protocol. It does not explicitly name alternatives or exclusion conditions, but the sibling tools are clearly unrelated, so an agent can infer the appropriate use case.

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