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

With no annotations, the description carries the transparency burden. It discloses output content (coordinates, rotation), limitations (door/flow ignored), and additional warnings (carry_in_warnings with risk levels). This gives the agent a good sense of behavior beyond just the tool's existence.

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 three sentences, front-loaded with the usage scenario, followed by process, output, limitations, and warnings. Every sentence adds distinct information with no 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?

Given there is no output schema, the description covers the main inputs, output type (coordinates/rotation), caveats (traffic not considered), and special warnings. It lacks details on optional parameters and exact output structure, but is sufficiently complete for an agent to invoke the tool correctly for typical use.

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 only 43%, so the description must compensate. It clarifies that room dimensions are effective dimensions, and that items list requires width/depth/count. However, it does not explain grid_step_mm, margin_between_mm, or wall_clearance_mm, leaving gaps for those optional parameters.

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 explicitly states that this tool is for checking if furniture fits, using room dimensions and a furniture list, and specifies that it returns coordinates and rotation. This clearly distinguishes it from siblings like suggest_by_space by focusing on placement simulation rather than product suggestion.

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 a concrete usage example ('部屋にベッドとデスクは入る？'), explains that doors and traffic flow are not considered (so results are estimates), and instructs how to handle carry_in_warnings. It does not explicitly name alternative tools, but the conditions for use are clear.

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