colorize_lineart

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

With no annotations, the description carries the full burden; it usefully explains the flood-fill behavior and the semantics of transparent_color for leaving areas empty. However it never says whether a new layer is created (the 'name' default of 'Colourise' hints at it), whether the operation is destructive or undoable, or how it interacts with an existing layer.

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 tight sentences with the core action and the region format front-loaded, no filler. The inline JSON fragment is slightly awkward but earns its space as the only specification of the regions structure.

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 six-parameter mutation tool with no annotations and no output schema, the description covers only the regions shape and transparent_color. It omits return values, whether a layer is created or modified, and the meaning of cleanup/edge_detection, which an agent needs before calling 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 must compensate, and it does well for 'regions' — supplying the exact object shape with color/points or color/rect, which the schema only types as a generic object array. But 'name', 'layer', 'cleanup' (default 0.7), and 'edge_detection' are entirely unexplained, leaving four of six parameters opaque.

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?

Opens with a specific verb+resource: "Flat-colour line art with Krita's Colourise Mask," and explains the underlying mechanism (flooding each scribble's colour up to the lines). An agent can distinguish this from generic painting tools like brush_stroke or fill_selection, though no sibling is named explicitly.

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 statement of when to use this versus alternatives such as fill_selection, apply_filter, or brush_stroke, and no prerequisites (e.g. whether a line-art layer must be active). Usage is only inferable from the mechanics described.

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