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

With no annotations, the description carries the full behavioral burden. It usefully discloses the result composition (11 of 12 have a human/legal owner of record; 1 Wellknown verifies no identity) and that each row carries agent_as_principal, but it omits operational traits such as read-only nature, format, pagination, or any auth requirement.

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?

Purpose is front-loaded in the first sentence, followed by domain context and a field note. It is dense and a touch verbose, but every sentence contributes to interpreting the rows rather than padding.

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?

No output schema exists, so the description must explain what is returned; it does explain the meaning of rows and the agent_as_principal field, but not the literal return shape or size of the list. Adequate but with clear gaps for a no-annotation, no-output-schema tool.

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 tool takes no parameters, so there are no parameter semantics to convey and the baseline of 4 applies. The empty schema is fully self-consistent with the 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: 'List every service that documents an identity a non-human actor may hold.' An agent can tell this is an enumeration of identity routes. It does not, however, contrast itself with the sibling can_an_agent_hold_an_account, so differentiation is left implicit.

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?

There is no explicit when-to-use or when-not-to-use guidance, and the sibling can_an_agent_hold_an_account is never mentioned as an alternative. The reader must infer that this lists routes while the sibling answers a yes/no question.

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