add_instanced_static_mesh_component

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

Annotations already declare idempotentHint=true, but the description goes further by explaining the exact repeat-call behavior ('returns that one with already_existed=true instead of adding a second') and by surfacing a non-obvious environmental constraint (foliage tools crash this build). It also documents the return shape in the absence of an output schema.

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-loaded with the core action, then workflow rationale, then idempotency semantics, then return shape. Every sentence is load-bearing and there is 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?

With no output schema present, the description supplies the return fields itself and covers chaining, idempotency, and the crash-related caveat. An agent has everything needed to call it and to know what follows.

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 both parameters are already documented in the schema; the description adds only the contextual detail that actor_name targets a 'placed editor-world actor.' Baseline 3 is appropriate when the schema carries the parameter documentation.

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 (attach) and resource (InstancedStaticMeshComponent) and ties it to an explicit downstream workflow ('so you can then scatter... with add_ism_instance'). It is clearly distinguishable from generic sibling tools like add_component_to_actor and add_foliage_instances.

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 the when (attach an ISM before scattering), names the downstream tool (add_ism_instance), and explicitly excludes the alternative ('the working alternative to the foliage scatter tools, which crash the editor'). Both the alternative and the condition selecting it are stated.

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