Update own @username

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

With annotations openWorldHint=true and idempotentHint=true already covering side effects and idempotency, the description adds value by disclosing the clear behavior via empty string. No contradiction with 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?

The description is a single short sentence (9 words) that conveys the essential operation and special case. Every word earns its place; no fluff or redundancy.

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?

The tool is simple, but with no output schema and 0% parameter coverage, the description should offer more context. It covers the main purpose and clearing behavior, but fails to mention the role of accountId, making the definition incomplete for a two-parameter 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%, so the description must compensate. It explains 'username' as the value to set, but completely omits the optional 'accountId' parameter, leaving its purpose ambiguous. This is a significant gap for parameter understanding.

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 specific verb 'Set or clear' and resource 'own public username', clearly distinguishing from sibling 'update_username' which likely targets other entities. It also clarifies the special empty-string behavior for clearing.

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 phrase 'own public username' makes it clear this is for the current user, not channels/groups. However, it does not explicitly state when to prefer this over update_username or mention prerequisites like authentication, though context implies it.

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