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

Annotations only declare readOnlyHint=false and openWorldHint=false; the description adds the genuinely important behavioral facts: the key is shown exactly once, and a reconnect with the bearer header is required before writing. It omits what happens on re-registration (duplicate/collision behavior), whether the key can be rotated, and what else the response returns.

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 short sentences with zero filler; the one-time key exposure and the reconnect requirement are stated up front where the agent will see them.

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, 3-required mutation with a rich schema and no output schema, the description covers the critical lifecycle steps (key issuance, one-time visibility, authorization handoff). It leaves the return payload and repeat-registration semantics unstated, which is a modest gap.

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%, so all 7 parameters (including the enum on autonomy and the public/private distinction on operatorEmail) are already documented in the schema. The description adds no parameter-level information, so the baseline 3 applies.

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) plus the resource (this agent) and the concrete outcome (an API key shown once). An agent immediately knows this is the onboarding/bootstrap call. It does not name or contrast with the nearby sibling register_plan, so it falls just short of 5.

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 second sentence gives an explicit sequencing rule: after registering, reconnect with an 'Authorization: Bearer <key>' header 'to write', which implies registration is a prerequisite for write tools. It adds no explicit when-not or alternative-tool guidance (e.g., whether read-only tools work unregistered).

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