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

Adds value beyond the readOnlyHint annotation by disclosing the exact return payload and noting the call is cheap, implying no rate/cost concern. It does not discuss error behavior on an invalid token, which keeps it out of 5 territory.

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?

Three short clauses, front-loaded with the primary purpose, then the usage rationale, then the endpoint reference. Every sentence earns its place with no filler.

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 input parameters and no output schema, the description carries the burden of describing the return content and it does so explicitly, plus it names the underlying endpoint. Nothing an agent needs to call it correctly is missing.

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 the description cannot add parameter meaning and the baseline for a parameterless tool applies. No gaps or ambiguity introduced.

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?

Precise verb+resource ('Return the Deputy user the token belongs to') and it enumerates the returned fields (name, employee id, company, permissions). This clearly distinguishes it from siblings like deputy_get_employee, which targets a specific employee rather than the token's owner.

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?

Explicitly frames the use case: 'A cheap way to confirm DEPUTY_INSTALL and the token are right.' That tells an agent when to reach for it, though it does not name an alternative tool or state when not to use it, so it stops short of a 5.

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