Get user

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

Beyond the readOnlyHint and destructiveHint annotations, the description discloses valuable behavioral details: it returns computed summary data (data left, days left, usage percent) and handles the edge case where a user is effectively expired even before the status field catches up. This goes well beyond what annotations provide.

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?

The description is a single dense sentence, front-loaded with the core operation and followed by relevant computed-summary details. Every clause adds value and there is no redundant or filler content.

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 only one parameter, an output schema present, and readOnly annotations, the description is sufficiently complete for a getter tool. It explains the single input, the summary output, and an important semantic edge case, leaving no critical gap for an agent to misuse the tool.

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?

Schema description coverage is 0%, and the description only repeats the parameter name ('by username') without adding extra meaning such as exact-match behavior, case sensitivity, or how the username relates to the summary computation. The schema already provides constraints, but the description does little to compensate for the lack of parameter documentation.

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 ('Fetches') and a specific resource ('one user by username'), clearly distinguishing this tool from sibling tools like marzban_users_list that return multiple users. The mention of the computed summary further clarifies the tool's unique purpose.

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 clearly indicates this is for fetching a single user by username, which gives the agent a clear context for when to use this tool. However, it does not explicitly name alternatives or state when not to use this tool, so it falls just short of full explicit guidance.

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