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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds context annotations cannot carry: no account required, and the exact content of the record (endpoints, per-tool input schema, free/priced/key status, uptime, latency, reputation). It does not mention rate limits or freshness of the reputation data, so it stops short of 5.

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?

Front-loaded with the payload, then usage, then routing to siblings, then the read-only note — a sensible order with no filler sentences. The first sentence is long and list-heavy, which slightly slows scanning, but every clause carries information.

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?

No output schema exists, and the description compensates by enumerating the returned fields (endpoints, tools with schemas, pricing state, uptime, latency, reputation). With one parameter, no auth, and a single JSON record return, nothing an agent needs to call this correctly is missing.

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 0% and the single id parameter has no description, so the description must compensate. It does so meaningfully by specifying provenance ('the id search_agents returned'), which tells the agent where a valid value comes from, though it adds no format or example.

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 ('Everything the registry knows about one listed agent, by the id') and immediately disambiguates from siblings by naming agent_liveness and verify_endpoint as the tools for adjacent needs. An agent can tell it apart from search_agents, agent_trust, and describe_tools without opening any schema.

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?

Explicitly says to use it after search_agents to decide whether and how to call an agent, and routes two other cases (check history, unlisted URL) to agent_liveness and verify_endpoint. This is a full when-to-use plus when-not-to-use mapping.

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