list_agents

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

No annotations are provided, so the description must convey safety and behavioral traits. It states the directory is 'public,' implying read-only access, and lists the exact content returned, which is useful transparency. It doesn't disclose pagination or sorting behavior, but the schema includes page/pageSize parameters, partially covering that.

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 two concise sentences, front-loaded with a clear action verb and resource. Every word contributes to understanding the tool's purpose and output.

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 paginated list tool with no output schema or annotations, the description covers the core purpose and return content. It could explicitly mention pagination or query behavior, but the schema already documents those parameters, making the description reasonably complete.

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 input schema provides 100% description coverage for all three parameters (page, query, pageSize). The description adds no additional parameter-specific semantics beyond what the schema already states, so the baseline score 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 uses a specific verb 'Search' and resource 'public agent directory', clearly stating what it does. It also enumerates the returned data (registered agents, mail addresses, trust scores, reviews, ED25519 verification status), which distinguishes it from sibling tools focused on messaging or identity.

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?

Implied usage is clear: use this tool to search the public agent directory for agent information. However, it doesn't explicitly mention when not to use it or name alternative tools, though siblings like check_identity serve a different purpose. The context is sufficient for an agent to select it appropriately.

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