gimp_fill

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

Annotations declare readOnlyHint=false, destructiveHint=false, openWorldHint=false, so the write/non-network profile is already covered. The description usefully adds the selection-vs-whole-layer scoping rule, but says nothing about whether existing pixels are overwritten or the operation's irreversibility. Nothing here contradicts the annotations.

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?

Two compact sentences with the primary behavior (what gets filled) front-loaded and the parameter values following. No wasted text; the only minor issue is that the fill-value list is dense inside the second sentence.

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?

An output schema exists, so return values need no explanation. Still, for a 3-parameter tool at 0% schema coverage, the description omits how image_id/layer_id resolve (defaults, active image/layer behavior), which an agent needs in order to invoke it correctly.

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%, so the description carries the burden. It does enumerate the accepted fill values including the missing enum (foreground, background, white, transparent, pattern, hex color), which is genuinely useful. But image_id and layer_id are left completely unexplained, so the compensation is only partial.

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?

States a specific verb (fill/rellena) and the exact resource affected: the current selection, or the whole layer when no selection exists. It is unambiguous about what the tool does, though it does not name any sibling to differentiate itself from tools like gimp_draw, gimp_gradient, or gimp_stroke_selection.

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 parenthetical '(o la capa entera si no hay selección)' implicitly defines the operating context and the fallback behavior when no selection exists. However, there is no guidance on when to prefer this over related painting tools (draw, gradient, stroke) and no prerequisites stated.

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