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

Annotations already declare readOnlyHint=true and idempotentHint=true, and the description adds useful specifics about what the returned identity contains. It doesn't describe failure behavior (e.g., unauthenticated), but that's a minor gap given the annotation coverage.

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, front-loaded sentence with zero filler. The parenthetical list of return fields is concise and every part earns its place.

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?

For a zero-parameter, read-only identity tool, the description covers what it returns and under what auth context. No output schema is present, but the listed fields provide sufficient guidance for an agent.

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 has zero parameters, and the schema is empty. Baseline for 0 params is 4. The description adds no parameter info, but none is needed since there is nothing to document.

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 uses a specific verb ('Return') and resource ('identity of the currently authenticated Sunago Matrix user'), and includes the exact fields returned (auth id, email, employee id, workspace, feature permissions). This clearly distinguishes it from the many sibling tools, none of which target current-user identity.

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 makes the context obvious: use when you need the current user's identity. It doesn't explicitly name exclusions or alternatives, but no sibling tool overlaps with this purpose, so the guidance is clear enough without them.

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