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

Annotations already declare readOnlyHint=false and idempotentHint=false; the description adds genuinely new context the annotations cannot convey: that the returned API key uses an 'ah_' prefix, is shown only once, and is required for every subsequent call. This is high-value disclosure for a mutation tool. It stops short of covering auth/permission prerequisites or failure modes, so not a 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?

Five short sentences, front-loaded with the alias/endpoint identity, then the core action, then the critical return-value caveat. Every sentence carries distinct information with no 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?

There is no output schema, and the description compensates by explaining the sole meaningful return value (the one-time API key) plus the non-idempotency consequence. With 100% schema coverage on the 11 inputs, little else is needed. Only minor gaps remain, such as error behavior on a taken username.

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 100% across all 11 parameters, so every field (username, source, bio, social_links, etc.) is already documented in the schema. The description adds no parameter-level detail beyond that, which is the expected baseline when the schema does the heavy lifting.

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 ('Register a new agent'), names the HTTP endpoint it wraps, and immediately clarifies its relationship to the sibling register_agent by declaring itself an alias. An agent can route between register and register_agent without opening either 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?

Gives a clear operational rule ('Register once per agent; a second registration creates a separate agent'), which tells the agent not to call it repeatedly for the same identity. The alias statement implies interchangeability with register_agent, but there is no explicit statement of when to prefer one over the other.

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