add_field_node

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

Annotations already declare readOnly=false, idempotent=false, destructive=false, so the safety profile is known. The description adds behavior the annotations don't: it appends to UFieldSystem.Commands and saves the asset, and the return block surfaces a save_error, which is useful for a non-idempotent mutator. It does not discuss permission requirements or what happens on repeated calls explicitly.

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 action and its persistence are front-loaded, and the parameter guidance is compact. The middle sentence describing internal C++ mechanics (transient authoring node, FFieldObjectCommands::CreateFieldCommand, appending to Commands) is more implementation detail than an agent needs, though it does double as behavioral disclosure.

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 19-parameter tool this is thorough: it enumerates the node types, the target attribute classes and their pairing rules, the falloff values, and it inlines a return-value shape despite there being no output schema. An agent has enough to construct a valid call without external references.

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 baseline is 3. The description goes beyond the schema by enumerating the accepted falloff_type values ('Inverse', 'Squared', 'Logarithmic', 'None') and by explaining how node_type classes pair with target classes, which the schema does not state.

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 first sentence states a specific verb and resource ('Author a field command node into a UFieldSystem and persist it'), which is precise enough to separate it from create_field_system_asset, get_field_system_info, and remove_field_node without opening any schema. It also clarifies the node is created and persisted, not just described.

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 gives real selection guidance for the required params ('Vector nodes pair with vector targets (LinearVelocity/LinearForce); scalar with strain/threshold; integer with state'), which is the main decision an agent faces. It stops short of stating when to prefer this over the sibling remove_field_node or the asset-creation tool, so no explicit exclusions.

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