set_decal_fade_in

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

Annotations already declare destructiveHint=true and idempotentHint=true, so the safety profile is covered. The description usefully tells the agent which fields are mutated and the return shape, but never explains why the operation is flagged destructive (e.g. overwriting existing fade values).

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?

Front-loads the action and target, then the differentiating parenthetical, then the return shape in a compact line. Every part earns its place, though the return object restates schema-obvious fields.

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?

With no output schema, the description supplies the return shape, names the target component, and covers all three parameters via the schema. Adequate for a simple setter, though it omits persistence/undo implications of the destructive annotation.

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 schema already documents duration and start_delay with defaults and units. The description maps them to the underlying FadeInStartDelay/FadeInDuration fields, adding minor semantic value but no syntax or constraint detail beyond the schema.

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 (Set) and the exact resource (FadeInStartDelay and FadeInDuration on a UDecalComponent). It explicitly distinguishes itself from the sibling SetFadeOut path by noting this command sets the *in* pair, so an agent can tell it apart without opening a schema.

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?

Gives clear context for when to use this tool: when you want the fade-in fields rather than the fade-out fields handled by the other command. It names the alternative behavior but not the exact sibling tool names (e.g. set_decal_fade), leaving a small inference gap.

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