clear

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

Annotations already declare readOnlyHint=false and destructiveHint=true, and the description aligns with that by stating cels are cleared to transparent (or overwritten with a color), which is genuinely additive detail about what is lost. It does not disclose undo/reversibility, the live-vs-batch implications, or the default save-to-file behavior, so it only modestly exceeds what annotations provide.

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 dense sentence that front-loads the core action and appends the fill alternative and the three scope modes without wasted words. No filler, 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?

For a 12-parameter, destructive, no-output-schema tool, the description covers the operation and its target granularity but omits operational context such as batch-mode/save semantics, live-vs-batch behavior, and reversibility. The rich schema compensates for the parameter gaps, but behavioral context is thin.

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 83%, above the 80% threshold, so the schema already documents nearly all 12 parameters thoroughly (color formats, frame ranges, tags, sprite/layer targeting, save flag). The description restates the targeting modes but adds no syntax or format meaning beyond the schema, so the baseline 3 applies.

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 (clears) and resource (a layer's cel(s)) with the outcome spelled out: to transparent, or filled with a color. The three target scopes (whole cel, rect, selected area) further pin down what it does. It does not name or contrast with the obvious sibling delete_cel, so it stops short of full sibling differentiation.

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 enumerates the ways the region can be targeted but gives no when-to-use guidance, prerequisites, or exclusions relative to alternatives like delete_cel, draw_pixels, or replace_color. An agent must infer selection from the parameter schema alone.

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