token_bowl_chat_update_my_username

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

With no annotations, the description carries the full burden and largely meets it: it discloses that the change takes effect immediately, that uniqueness across all users is enforced, and names the failure modes (ConflictError, ValidationError). It stops short of stating auth/permission requirements or reversibility.

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 key sentence is front-loaded and the Args/Raises sections are compact. The Returns block is somewhat redundant given an output schema exists, but the overall structure is scannable and low-waste.

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 mutation the definition covers input constraints, error conditions, and effect timing, which is sufficient. Missing only auth/prerequisite context that the absent annotations would normally supply.

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 0%, so the description must compensate, and it does: the Args block documents new_username and adds the 1-50 character constraint not present in the schema. It lacks format details beyond length, so it is not exhaustive.

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 ('Change') and resource ('your Token Bowl Chat username'), and the 'my' scoping distinguishes it from the admin sibling token_bowl_chat_admin_update_user. An agent can identify the operation without opening the schema.

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 second sentence, 'Use this to update your account username,' merely restates the first line and adds no when/when-not guidance. No alternative tool or precondition (e.g., admin update vs self update, auth requirement) is mentioned.

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