楕円マスクを作る

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

With no annotations provided, the description carries the full burden. It discloses the ratio-based coordinate system (0-1) and gives examples, which is valuable. However, it does not mention potential side effects like file overwriting or the exact mask format characteristics beyond 'PNG'.

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 two sentences, front-loading the purpose, then adding coordinate semantics and examples. It is concise and every sentence contributes useful information without redundancy.

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 description covers the core behavior, coordinate system, and examples, which is largely sufficient for invoking the tool correctly. Gaps exist regarding expected mask appearance (e.g., fill color) but given no output schema and no annotations, the description does enough to guide an agent.

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 only describes like_path and out_path, leaving the four coordinate parameters undocumented. The description compensates by explaining the ratio coordinate system and providing specific example values for left/top/right/bottom, adding essential meaning beyond the bare schema.

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 tool's function: creating a mask PNG that specifies an elliptical editing region (e.g., mouth, eyes). It provides concrete coordinate examples, making the purpose unambiguous and distinguishing it from sibling tools like generate_image or compose_region.

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 implies usage for facial region editing through examples, but does not explicitly state when to use this tool versus alternatives or mention any exclusions. The context is clear but lacks explicit guidelines about alternatives or when not to use it.

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