set_onion_skin

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

With no annotations present, the description carries the full burden of behavioral disclosure. It does reveal one useful behavior—Aseprite UI-only settings are 'reported explicitly'—but it does not clarify whether the operation mutates state, what happens to invalid settings, whether filename refers to a document or project file, or what the return/report looks like.

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 a single efficient sentence with the main action front-loaded and no filler. The semicolon clause adds important context about UI-only settings, though it could be clearer with a more explicit subject-verb 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 tool with five parameters, no output schema, no annotations, and 0% schema coverage, the description is too thin to be fully actionable. It gives a high-level purpose but fails to clarify parameter behavior, expected outputs, side effects, or failure modes, which an agent needs to call this tool reliably.

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 needed to compensate by explaining parameter meaning, but it does not mention before, after, enabled, opacity, or filename at all. The phrase 'onion-skin settings' loosely contextualizes the parameters, but the agent is left to infer semantics from bare property names and defaults.

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 states a specific function: validating onion-skin settings in batch workflows, and adds a distinctive reporting behavior for Aseprite UI-only settings. It distinguishes the tool from related siblings like render_onion_skin and compare_frames, though the verb 'validate' sits slightly at odds with the tool name 'set_onion_skin', leaving mild ambiguity about whether it actually applies settings or only checks them.

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 gives a clear usage context ('for batch workflows') and implies the tool should be used when you need UI-only settings surfaced rather than silently dropped. However, it never explicitly states when to choose this tool over alternatives or when not to use it, leaving the routing decision to the agent.

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