Get reseller user

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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered. The description goes beyond them by disclosing failure behavior (403 for non-reseller accounts) and a configuration-dependent unavailability condition tied to MXROUTE_USERNAME, which an agent cannot infer from the schema or annotations.

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 tightly packed sentences with zero filler: returned fields first, then eligibility and environment constraints. Every clause carries actionable information.

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 single-parameter read tool with full annotations and no output schema, the description covers return fields, error behavior, and environment preconditions. It stops short of noting behavior for a nonexistent/invalid username, which is the only notable 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?

There is a single required parameter with 100% schema description coverage, so the schema already documents the argument format ('johndoe'). The description adds no additional parameter-level detail, which is the baseline when schema coverage is complete.

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 a specific verb ('Returns') and resource (a reseller user's record) and enumerates the exact fields returned (email, primary domain, package, suspended state, disk quota). This clearly separates it from the sibling list_reseller_users, which returns a collection rather than a single user.

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?

Gives explicit conditions: reseller accounts only, with regular accounts refused (403), plus an environment precondition (unavailable while MXROUTE_USERNAME is in `reseller|user` form). It does not name a sibling alternative to use instead when the constraint fails, which keeps it 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.