create_character

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

With no annotations, the description carries the full burden of behavioral disclosure. It mentions the operation is synchronous and returns a result, but omits critical details such as side effects (is it a write/creation? are resources persisted?), authentication requirements, possible failure modes, or whether the operation is idempotent. This is insufficient for a create operation.

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 short (two sentences) but not optimally front-loaded. The first sentence 'Run a synchronous Gemini Omni operation on RunAPI (create character)' is indirect; a more direct phrasing like 'Creates a character using Gemini Omni on RunAPI' would be clearer. The second sentence about the return value is useful, but the structure feels slightly awkward.

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 has 5 parameters, no output schema, and the description does not explain what the operation result actually contains (e.g., a task ID, character data, or error details). There is also no mention of how this tool fits into a workflow (e.g., whether it depends on create_audio to provide audio_ids). Given the complexity and lack of output schema, the description is incomplete.

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 input schema has 100% description coverage for all 5 parameters, so the schema already explains the meaning of fields like descriptions and reference_image_url. The description adds no additional parameter semantics beyond what the schema provides, making a baseline score of 3 appropriate.

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 identifies the tool as creating a character via a Gemini Omni operation on RunAPI, which is a specific verb+resource combination. It distinguishes from siblings like text_to_video and create_audio by focusing on character creation, though the phrase 'synchronous Gemini Omni operation' adds jargon without fully clarifying the action.

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 provides no guidance on when to use this tool versus alternatives such as create_audio or text_to_video. No exclusions, prerequisites, or contextual triggers are mentioned, leaving the agent to infer usage from the tool name alone.

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