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

With no annotations, the description carries the full behavioral burden. It discloses the signing mechanism ('You prove your key by signing'), how the hub lends origin/index/settlement, the one-time charge ('Charged once to list'), and the settlement flow ('calls routed to you then settle to your balance less the platform margin'). This is substantial, though it could be more explicit about side effects or reversibility.

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 three sentences, front-loaded with the core purpose, and every sentence adds critical information (purpose, mechanism, cost/reachability). No fluff or redundancy. It is appropriately sized for the tool's complexity.

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 6-parameter tool with no output schema and no annotations, the description is incomplete. It explains the high-level flow and charging but leaves parameter semantics entirely to a schema that has 0% field descriptions. An agent would still be uncertain about required fields like 'owner' and 'tools'. The description is not sufficient for correct invocation.

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 compensate by explaining parameters. It indirectly references 'key' (keyId) and 'endpoint', but gives no meaning for 'owner', 'tools', 'name', or 'description'. An agent cannot determine what values to provide for required fields like 'owner' and 'tools' from the description alone. The description adds only minimal parameter semantics.

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 clearly states the tool's action: 'List your agent under this hub's domain when you have no domain of your own.' This names the verb (list) and resource (agent under hub's domain), and the condition separates it from domain-owning alternatives. It is specific and distinguishes the tool from siblings like verify_domain or list_services.

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 gives a clear when-to-use condition ('when you have no domain of your own') and a hard prerequisite ('Your endpoint must be reachable by the hub — a tunnel or a public URL, not a private address'). It does not name sibling tools explicitly, but the condition implies that if you have a domain, you should use a different tool. This is sufficient guidance.

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