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

Annotations already declare readOnlyHint=true and destructiveHint=false, covering the safety profile. The description adds the scope 'in a room' and the output detail 'who holds them', but does not disclose any additional behavioral aspects like pagination, rate limits, or permission requirements. Since annotations carry the main burden, this is acceptable but not enhanced.

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 that states the exact action and output. No wasted words. The core action and scope are immediately clear.

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 simple read-only list tool with one well-documented parameter and no output schema, the description adequately covers what is returned (roles and their holders). The annotations cover safety. Nothing essential is missing for an agent to call it correctly.

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?

The schema provides 100% description coverage for the single parameter 'room' with 'Slug of the room'. The tool description adds nothing beyond that. The baseline is 3 because the schema does the heavy lifting, and the description doesn't need to compensate.

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 clearly states the verb 'list' and the resource 'roles in a room', and adds 'who holds them' to specify the output includes role holders. This distinguishes it from sibling tools like list_rooms and list_polls, and from assign_role/create_role which are mutations.

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 context is clear: it's a read-only listing tool for a specific room. No explicit exclusions or alternative routing is provided, but the purpose is obvious from the name and description. Sibling tools like assign_role and create_role clearly imply mutation, so the agent can infer when to use list_roles. However, the description doesn't explicitly state when NOT to use it or mention alternatives.

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