Get user profile

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

Annotations already declare readOnlyHint=true, covering the safety profile. The description adds minor behavioral context (accepts usernames with or without leading @) but says nothing about response contents or behavior for unknown usernames.

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 redundancy. Every phrase ('by username', 'with or without leading @') contributes to correct invocation.

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 one-parameter read-only lookup this is nearly complete. The only gap is that no output schema exists and the description doesn't enumerate profile fields or error behavior, though 'profile' gives a reasonable default expectation.

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 coverage is 100%, and the schema description ('Username, e.g. 'jane' or '@jane'') already conveys the @-tolerance that the description restates. The description adds no meaning beyond the schema's baseline.

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 ('Look up') and resource ('Mattermost user's profile') with the lookup key (username). The '@' format detail adds precision, and the description clearly distinguishes it from siblings like whoami (which targets the current user) since it targets a named 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?

The description implies when to use it — when you have a username and need profile details — but it names no alternatives or exclusions. The closest sibling whoami is never contrasted, so an agent receives no explicit routing guidance.

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