add_niagara_emitter_handle

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

Annotations already declare readOnlyHint=false, idempotentHint=false and destructiveHint=false. The description adds real value beyond that: it discloses the sequence (load asset, resolve exposed version GUID, call AddEmitterHandle) and, importantly, the side effect that 'the system is saved after modification.' It does not cover failure modes or permissions, keeping it short of 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?

Three tight sentences, front-loaded with the action and its source, followed by mechanics and the return shape. The Returns block is somewhat dense but earns its place because no output schema exists. No filler or repetition.

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?

This is a mutation tool with a side effect (saving the system), and the description discloses that plus the full return shape, compensating for the absent output schema. It lacks any error-handling or permission context, but for a 3-param tool with full schema coverage and annotations, an agent has enough to invoke it correctly.

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 system_path, emitter_name, and emitter_path with examples and defaults. The description only restates that an existing emitter asset is the source; it adds no format or constraint 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?

Specific verb+resource: 'Add an emitter to a Niagara system from an existing UNiagaraEmitter asset.' The qualifier 'from an existing UNiagaraEmitter asset' distinguishes it from sibling add_niagara_emitter_from_template without needing to name it. An agent can select this over other add_niagara_* tools on purpose alone.

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 explains the mechanics of how the emitter is added but never states when to use this versus add_niagara_emitter_from_template or create_niagara_system, nor any preconditions. Usage is implied by the verb, which meets the minimum-viable bar but offers no exclusions or alternatives.

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