add_node

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

Annotations already indicate readOnlyHint=false and destructiveHint=false, so the mutation nature is clear. The description adds a behavioral detail about defaulting to root when parentNodePath is omitted, but does not disclose other potential side effects (e.g., whether the file is auto-saved, existing node behavior, or prerequisites). This is adequate but not rich.

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 description is two sentences with no redundancy. It immediately states purpose, gives a useful default, and points to an alternative. Every word earns its place, perfectly concise and well-structured.

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 mutation tool with no output schema, the description covers the essential context: what it does, the default parameter behavior, and a relevant alternative. It could mention return behavior or side effects, but given the moderate complexity and schema richness, it is sufficiently complete for an agent to select and invoke 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 coverage is 100%, giving a baseline of 3. The description adds meaningful param semantics by explaining the default behavior for parentNodePath when omitted, which is not in the schema. This extra context justifies a score above baseline.

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 description clearly states the action (add a child node) and the resource (a scene file on disk), and distinguishes from a sibling tool by explicitly pointing to instantiate_scene for sub-scene instances. This meets the 'specific verb+resource' criterion and adds distinguishing context.

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 provides a clear alternative usage ('For sub-scene instances, use instantiate_scene') and implies the primary use case (adding nodes to scene files). However, it does not explicitly mention when not to use the tool beyond that one sibling, so it lacks exhaustive exclusions.

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