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

Annotations already declare readOnlyHint, destructiveHint=false and openWorldHint=false, so safety is covered structurally. The description adds modest value with 'right now' (live, not cached state) and 'this key' (scoped to the calling credential rather than the whole account). It says nothing about auth failure behavior or errors.

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?

A single sentence with no wasted words, front-loading the most decision-relevant item (owner verification) ahead of secondary fields. Nothing to trim and nothing repeated from the annotations.

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 an output schema present and no input parameters, the description need only justify selection, and it largely does. The remaining gap is behavioral context around authentication state, which none of the structured fields cover.

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 no parameter semantics to add beyond what the empty schema already communicates. Baseline 4 applies; the description does not need to explain inputs.

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 names the concrete contents returned: owner verification status, the caller's handle, and the scopes the current key holds. That is specific enough for an agent to distinguish this from get_balance or list_keys. It falls short of 5 only because it never names a sibling or states scope exclusions explicitly.

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?

Use cases are implied by the content list (check verification, read handle, inspect key scopes), so an agent can infer when to reach for it. There is no explicit when-to-use statement, no prerequisite (e.g. authenticated session), and no named alternative among the 20+ siblings.

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