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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=true, so the safety profile is fully covered. The description's 'does not create an identity' largely restates readOnlyHint rather than adding new behavioral context such as scope limits, pagination, or what constitutes an 'authorized' identity.

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, front-loaded with the action. The second sentence is defensively worded and mostly redundant given readOnlyHint, which slightly dilutes an otherwise efficient description.

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?

With no params, no output schema, and annotations carrying the behavioral profile, this is a low-complexity tool, but the description still leaves the identifier 'actor/identity' undefined and does not distinguish itself from create_actor or indicate what the returned list contains. Adequate but with clear gaps.

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 zero parameters, so there is nothing for the description to disambiguate; the baseline for a no-param tool applies. No parameter-level information is missing.

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 the authenticated user's authorized identities.' The scope ('authenticated user's') is clear and distinguishes it from a global actor listing. However, it switches terminology from the tool name ('actors') to 'identities' without mapping them, and never explicitly names its sibling create_actor as the write counterpart.

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 only usage signal is the negative clause 'This does not create an identity,' which hints at the read/write boundary with create_actor but never names it or states when this tool should be chosen. There are no prerequisites, no context about when an authenticated identity list is useful, and no alternatives offered.

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