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

Annotations already declare this is a non-idempotent, non-destructive write, so the safety profile is covered. The description adds two useful traits the annotations cannot convey: names must be unique within the account, and the new Agent is immediately paired with the caller's Profile. It says nothing about failure modes or what is returned on success.

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 sentences with no filler, and the core action is front-loaded before the uniqueness and pairing details. The semicolon-joined pairing clause is dense and slightly awkward to parse, 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 one-parameter creation tool with no output schema, the description covers the key facts an agent needs: what gets created, the uniqueness constraint, and the automatic pairing side effect. It does not say whether the created Agent's identifier is returned, which matters for follow-up calls such as pairing_code.

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% and the single name parameter is already documented with length bounds and an example, so the schema does the heavy lifting. The description adds one genuine constraint beyond the schema, the account-wide uniqueness of names, which affects retry/error behavior.

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 ("Create an Agent") plus the scope of the account it lands in, so the operation is unambiguous. It stops short of explicitly differentiating itself from list_agents or pairing_code beyond the closing clause, so it is clear but not fully sibling-routed.

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 final clause implies the alternative path: creating an Agent auto-pairs it with the caller's Profile, whereas other people must use pairing_code instead. That gives an agent a usable decision rule for the pairing scenario, but there is no explicit "use this when / do not use this when" framing.

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