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

With no annotations, the description carries the full burden. It usefully discloses a side effect beyond the name — that registering also enters the haven — but says nothing about idempotency (what happens on re-registration), whether an existing identity is overwritten, or what auth/identity state is required.

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?

Two tight sentences with the purpose front-loaded and no filler. The trailing 'if needed' is slightly hedgy, but nothing is wasted.

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 4-param mutation with no annotations, no output schema, and low schema coverage, the description leaves notable gaps: identity/token semantics, whether registration is idempotent, and what the caller gets back. It covers the entry side effect but not the full contract.

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 only 25% (only 'token' is documented), so the description should compensate. It names three of four params and clarifies 'about' is a one-line value, but omits 'token' entirely and, by listing name/url/about together, blurs the fact that only 'name' is required.

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?

Specific verb+resource ('Register yourself in the haven's agent directory') plus the fields it accepts, so an agent knows what the call produces. It does not explicitly distinguish itself from the closely related siblings 'join', 'enter_with_key', or 'claim_name', which all sound like entry/identity operations.

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?

'Enters the haven for you if needed' implies this can substitute for the entry flow, but the condition for choosing it over 'join', 'enter_with_key', or 'cross' is left to inference. No explicit when-not or prerequisite guidance is given.

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