fill_area

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

With no annotations provided, the description carries the burden of behavioral disclosure. It discloses key behaviors like automatic autotiling and re-bordering, and mentions layer defaults. However, it omits mutation aspects (overwriting existing tiles) and does not mention the dryRun preview capability or return behavior. This is a moderate disclosure.

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 (two sentences) and front-loads the core action, followed by behavior and layer guidance. Every sentence adds value 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?

For a tool with 8 parameters and no output schema, the description sufficiently covers the main functionality, autotiling behavior, and special handling for regions. It does not explicitly state destructive overwrite behavior, but the overall context is adequate for an agent to proceed.

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 100%, so baseline is 3. The description adds meaningful semantics beyond schema by explaining that tileId can be an autotile base or raw tile, and specifically how to use layer 5 with region numbers. This enriches parameter understanding.

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 fills a rectangular area of a map with one tile id, which is a specific verb+resource. It also distinguishes from siblings like set_map_tile or paint_tiles by emphasizing automatic autotiling and the ability to handle region ids.

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 clear context on when to use the tool (rectangular area fills with autotiling) and gives guidance for layers, including defaulting to layer 0 and using layer 5 for region ids. However, it does not explicitly name alternative tools or state 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.