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

With no annotations provided, the description carries the full behavioral burden and does well by revealing that this is asynchronous (returns a jobId), requires Pro plan, and needs a pre-existing character. It does not mention error cases, costs, or rate limits, which prevents a higher score.

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 compact and front-loaded: it states the purpose, the plan requirement, prerequisite, and polling flow in four sentences with no filler. Every sentence contributes useful information for an agent.

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 an asynchronous tool with no output schema and no annotations, the description covers the main flow well: prerequisites, plan requirement, jobId return, and status polling. Minor omissions like error/error polling specifics and detailed failure behaviors mean it is not fully complete, but it is strong for a generation 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 coverage is 100% and each parameter already has detailed descriptions, including constraints, defaults, enums, and the audioUrl/voiceNoteId relationship. The description adds only the idea that characterId must reference an existing character, which is mostly a usage note rather than new parameter-level semantics, so the baseline 3 applies.

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 states a specific action and resource: generating a talking avatar video from a character face plus audio and names related workflow steps. It does not explicitly differentiate from overlapping siblings like ryla_generate_lip_sync or ryla_generate_video, so it stops short of full sibling differentiation.

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 sets clear preconditions (Pro plan required, character must already exist) and gives a workflow: use ryla_list_characters to get characterId and poll ryla_generation_status for jobId. It does not explicitly state when to choose an alternative generation tool, so it lacks an explicit exclusion or alternative comparison.

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