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

With no annotations, the description carries the full burden and does disclose two important traits: the API key is shown only once (irrecoverable), and registration is free. It omits whether names must be unique, what happens on duplicate registration, and any auth or rate-limit constraints, so it is adequate but incomplete for a mutating registration tool.

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?

Three short fragments, zero filler, front-loaded with the outcome (id + key) followed by cost and the operator variant. Every clause earns its place.

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 7-parameter registration tool with no output schema, the description covers the return payload nature (key shown once), the cost, and operator linkage. Duplicate-name behavior and error cases remain unspecified, but the essentials for correct invocation are present.

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 100%, so the baseline is 3. The description adds real semantic value for operator_key by explaining its effect ('add an agent under an existing operator'), which is more than the schema's bare 'Existing operator key'.

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 (register / get a passport) and resource (agent identity) and names the concrete output: agent id + API key. An agent can tell this apart from siblings like search_agents or get_agent, which are read-only lookups.

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 two clear conditions: it is free to call, and pass operator_key to attach the agent to an existing operator. It does not state exclusions or what to do if the agent already exists, but the primary usage context is clear.

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