flood_fill

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

With no annotations, the description carries the disclosure burden; it does state that the operation modifies a contiguous matching-color region starting at (x, y). However, it omits behavior such as connectivity (4- vs 8-neighbor), out-of-bounds handling, and whether the canvas is mutated in place.

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?

A single, front-loaded sentence with no filler. Every word contributes to identifying the tool's behavior.

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 plus fully described schema is sufficient for basic invocation, but the absence of annotations and output schema leaves connectivity and side-effect semantics undocumented. For a simple mutation tool these are meaningful gaps that the one-line description does not close.

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 the baseline is 3. The description adds little beyond the schema, only hinting that x/y are the start coordinates and that color is the replacement value; the schema already documents each parameter.

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 names the tool's core operation ('Fills a contiguous area of matching color') and the starting point, which clearly identifies flood fill and distinguishes it from siblings like set_pixel or draw_shape. It is a specific verb+resource statement rather than a tautology.

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?

No explicit when-to-use or alternative routing is given, but the wording implies this tool is for filling a connected region of identical color, in contrast to setting individual pixels. There is no guidance on 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.