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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered. The description adds only the duplicate-avoidance rationale ('Reuse the requested character ID'), with nothing about pagination, ordering, or result scope.

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?

Two short, front-loaded sentences with no filler; the purpose leads and the guidance follows. The second sentence is slightly ambiguous ('the requested character ID') but still earns its place as the tool's stated rationale.

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 read-only list tool with annotations covering the safety profile, the description is serviceable, but with no output schema it never indicates what the list returns (avatar IDs, names, pagination), leaving the agent to guess at the result shape.

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 single parameter workspaceId has 0% schema description coverage (only a regex pattern), and the description says nothing about what the parameter means or its format. The 'requested character ID' phrase refers to a returned field rather than to the input, so the description does not compensate for the coverage gap.

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 and resource ('List existing live conversational avatars') and frames it as a pre-step to creating or editing an avatar, which implicitly distinguishes it from create_live_avatar and update_live_avatar. It stops short of naming those siblings explicitly, so an agent must infer the boundary.

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?

'before creating or editing one' gives a clear when-to-use condition tied to the create/update workflow. There is no explicit when-not-to-use guidance and no sibling is named as an alternative, so it falls short of a 5.

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