apply_gameplay_effect

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

Annotations already declare readOnly=false and destructive=true, so the safety profile is covered. The description adds behavioral context beyond that: the spec/context construction, that it is applied to self, and that the 'applied' flag reflects whether the engine returned a valid handle. It doesn't say what state gets mutated or whether the effect stacks, but the added mechanism detail is meaningful.

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 core action in the first sentence, then the return shape and alternative in a second block. It is dense but every clause (level semantics, context source, applied handle, sibling pointer) carries information; minor jargon ('outgoing spec', 'context') is the only friction.

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 helpfully enumerates the return object (actor_name, effect_class, level, applied). Combined with annotations carrying the destructive/idempotency profile and a fully described input schema, an agent has enough to invoke it correctly; only the runtime effect on existing actor state goes unstated.

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 100%, so the schema already documents actor_name, effect_class, and level (including the _C Blueprint class-path requirement and case-insensitive matching). The description only re-references 'the given level' and adds no syntax or format detail beyond the schema, so 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 precise verb+resource: applying a GameplayEffect class to an editor-world actor's ability system component, and details the mechanism (outgoing spec at given level, fresh context, applied to self). It explicitly contrasts with the sibling apply_multiple_gameplay_effects (which handles lists), so an agent can tell them apart without opening schemas.

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?

It routes the agent to the alternative for batch use ('apply_multiple_gameplay_effects applies a list'), establishing single-vs-multiple as the selection criterion. It doesn't state prerequisites or when-not-to-use conditions (e.g., missing ability system component), so it's clear context but not a complete when/when-not guide.

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