render_onion_skin

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

With no annotations, the description carries the full behavioral burden. It discloses that the tool produces a PNG, composites ghosted copies, and is non-destructive (renders only). It could mention that it does not modify the original file, but the behavior is well implied.

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 concise and well-structured: a one-sentence summary followed by a paragraph of context and a bullet-style parameter list. Every sentence adds value, and the key purpose is front-loaded.

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?

Given the tool's complexity (7 parameters, no output schema, no annotations), the description is complete. It explains the output format (PNG), the purpose of onion skinning, and all parameters with defaults. No gaps remain for an AI agent to infer.

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 description coverage is 0%, but the description covers all 7 parameters with clear explanations (e.g., frame_index starts at 1, before/after defaults, ghost_opacity range). This fully compensates for the missing schema descriptions.

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 it renders a frame with translucent onion-skin ghosts as a PNG. It explicitly connects the tool to checking motion continuity in animation, distinguishing it from sibling tools like export_frame or set_onion_skin by describing the batch-mode onion skinning use case.

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 explains when to use the tool (export for verifying in-between positions) but does not explicitly exclude alternative tools or state when not to use it. However, the context is clear enough for an AI agent to decide based on the purpose.

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