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

Annotations only indicate readOnly=false and destructiveHint=false, so the description carries the burden of explaining behavior. It adds meaningful constraints: the operation does not relocate the agent, and agents cannot decide the Approval Inbox. These are non-obvious behavioral details beyond what annotations provide.

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?

The description is two sentences with no filler. It front-loads the core action, then adds the two most important behavioral caveats. Every sentence 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 simple two-parameter tool with no output schema, the description covers the purpose, the identifier options, and an important limitation. It could be more explicit about requiring one of the two optional parameters and what attaching changes operationally, but these are minor gaps given the tool's simplicity.

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?

The schema already describes both parameters with 100% coverage, so the baseline is 3. The description adds value by signaling that human_email and principal_id are alternative identifiers ('email or existing principal_id'), implying that one of them should be supplied even though the schema marks both as optional.

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?

The description uses a specific verb ('Attach') with a clear resource ('this agent') and target ('a human principal'), and it disambiguates itself from a transfer operation by explicitly stating it does not move the agent to a different human. This distinguishes it from sibling tools such as check_transfer.

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 description implies when to use the tool through its purpose and clarifies a key negative case ('Does not move the agent to a different human'), but it never names an alternative tool or states explicit conditions for choosing this tool over a sibling. Usage guidance is mostly inferred rather than directly provided.

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