mod_symmetry

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

Annotations already signal destructiveHint=true and readOnlyHint=false. The description adds concrete behavior beyond that: mirroring across an axis and welding the seam, which explains why the tool is destructive. No contradiction with annotations.

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 concise bilingual clauses with no filler. It front-loads the core action and follows with a practical use case.

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 a fully documented schema and destructive annotations, the description supplies the necessary intent and the context where it is useful. It could have added one sentence about objects being modified or the modifier-stack behavior, but nothing critical is missing.

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%, so each of the 6 parameters already has a meaningful description. The tool description only reinforces axis and weldSeam without adding new details such as threshold units or object-selection behavior, which is acceptable at the 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 identifies a specific operation: 'mirror the object across axis and weld the seam (weldSeam)', and labels it a Symmetry modifier. This is distinct from sibling modifiers and from mirror_object, which only mirrors without the modifier/weld semantics.

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 a clear use case: 'Handy for left/right symmetric characters.' It does not explicitly name alternatives or when-not-to-use cases, so it stops short of full routing guidance, but the context is directly actionable.

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