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

Annotations declare readOnlyHint=true, and the description reinforces that this is a pure read by listing exactly what is exposed. It goes beyond the annotations with a non-obvious behavioral rule: every yyyy-MM-dd date filter is interpreted in tenantTimezone, which affects how the agent must reason about other tools' inputs.

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, both load-bearing: the first names the return payload, the second delivers the timezone caveat. The most consequential information (tenantTimezone semantics) is front-loaded into the same sentence as the output list.

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 output schema, the description must enumerate return fields, and it does (tenant ID, user ID, role, tenantTimezone). It omits error/unauthenticated behavior and possible role values, which is acceptable for a zero-parameter diagnostic tool but leaves a small gap.

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. Baseline 4 applies; the description correctly does not invent parameter guidance where none is needed.

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 (Show) and resource (current authentication info) and enumerates the returned fields: tenant ID, user ID, role, and tenantTimezone. No sibling tool in the list returns identity context, so it is unambiguously distinguishable.

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 gives an explicit operational directive for using the returned value: compute "today" or "yesterday" in tenantTimezone rather than UTC. It does not state when to call the tool versus alternatives, but no sibling offers comparable identity/timezone data, so the omission is minor.

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