Copy / mirror a region

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It discloses 'one undo step', explains the default destination when x/y are absent, and details the flip semantics through a worked example. It does not explicitly state that the destination pixels are overwritten (though skipTransparent in the schema implies it) or mention any other side effects, which keeps it from a 5.

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 reasonably concise: two sentences plus an example. It front-loads the core operation, then adds default behavior and a concrete illustration. The example is valuable but makes it slightly longer than strictly necessary, so it does not receive a 5.

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 9 parameters and no output schema, the description covers the important behavioral nuances: destination defaults, flip semantics, and undo grouping. It leaves detailed parameter defaults to the schema (which is complete), and the example helps anchor usage. A fully complete description might also mention overwrite behavior explicitly, but the schema's skipTransparent covers that indirectly.

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 coverage is 100%, so the baseline is 3. The description goes beyond the schema by explaining the interaction between x/y and the source rectangle: without x/y it writes back in place. The symmetry example clarifies how rect, flip, and x combine, adding meaningful semantics that the schema alone does not convey.

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 uses a specific verb ('Copies a rectangle of pixels') and specifies the resource (pixels/region) and the optional operations (flipped, to another position/layer/frame). It distinguishes itself from siblings like aseprite_set_pixels or aseprite_draw by emphasizing the copy/mirror action and the 'one undo step' behavior.

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 clearly implies when to use the tool: to copy or mirror a region, with explicit context about the default behavior when x/y are omitted ('writes back in place'). It gives a concrete symmetry example that illustrates a typical use case. It does not explicitly name alternative tools or offer exclusions, but the context is clear enough to route an agent.

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