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

Annotations already declare readOnlyHint=false (a mutation), openWorldHint=true, and idempotentHint=false. The description adds the 'owner permission' authorization requirement for returning guests, which is real value, but is silent on non-idempotency (re-registering creates a new identity) and on what the returned credentials grant.

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: purpose and outputs first, then the new-vs-returning input branch. No filler, and the most decision-relevant constraint (which parameters apply) is front-loaded.

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?

An output schema exists so return values need no explanation, and the core registration flows are covered. However, for a 9-parameter tool with 0 required fields, six parameters remain unexplained anywhere, leaving the agent without guidance on what they do or whether they matter.

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% across 9 parameters, so the description must compensate. It meaningfully explains name, agent_id, and api_key and their mutually exclusive usage paths, but leaves source, is_test, industry, visit_id, owner_name, and organization entirely undocumented in both schema and description.

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 your agent for a resort stay') and clarifies the outputs (agent_id, stay_id, api_key), which implicitly distinguishes it from siblings like resort_check_out and resort_passport that consume those credentials. It stops short of explicitly naming a sibling it is not, so it lands just below the top.

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 clear conditional usage: new guest supplies name, returning guest supplies agent_id + api_key 'with owner permission'. That is actionable routing for the two main paths, though it never states when to prefer this over an alternative tool or any when-not conditions.

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