add_mesh_instance

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

With no annotations, the description must disclose behavioral traits. It mentions that 'rotation is in degrees', which adds some parameter context, but it omits any side effects, such as whether adding the node replaces existing nodes, the impact of parent_path, or the behavior of mesh_properties. The write nature is implied by 'Add' but not elaborated, and no other behavioral secrets (e.g., coordinate system, scaling behavior, material handling) are disclosed.

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 a single sentence, directly front-loaded with the action and resource. It wastes no words and efficiently conveys the core purpose. However, it omits necessary details about other parameters and usage context, walking a fine line between conciseness and under-specification. Still, as written, it is structurally clean and readable.

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?

Given the tool's complexity (8 parameters, no annotations, no output schema), the description is incomplete. It doesn't explain parameter formats (e.g., scale/position accept string, array, or object), the purpose of mesh_properties, or how parent_path works. It also lacks any context about the result of the operation or potential side effects, leaving the agent to guess on several important aspects.

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 0%, so the description must compensate. It references 'mesh_type' and 'mesh_file' and clarifies rotation units, but leaves six other parameters (name, scale, position, parent_path, mesh_properties) undefined. Even for the mentioned parameters, it doesn't explain valid values for mesh_type (though the schema has an enum) or the relationship between mesh_type and mesh_file. The description only partially compensates for the complete lack of schema descriptions.

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 tool's purpose: 'Add a MeshInstance3D' with a specific verb ('Add') and resource ('MeshInstance3D'). It further distinguishes between two input modes ('primitive mesh_type or a mesh loaded from mesh_file') and notes rotation units, making it distinct from sibling tools like 'add_node' or 'add_scene_instance'.

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?

No guidance is provided on when to use this tool versus alternatives. It does not mention exclusions, prerequisites, or contrast with siblings like 'add_scene_instance' for loading external scenes or 'add_node' for generic nodes. The only usage hint is the binary choice between mesh_type and mesh_file, which is more about parameter selection than situational context.

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