assign_vertex_group

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

With no annotations, the description carries the behavioral burden and does so well: it discloses group creation, the effects of REPLACE/ADD/SUBTRACT/REMOVE, weight range, and selection behavior. It does not discuss error conditions or undo/reversibility, so it falls short of the most complete disclosure.

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 front-loaded with the core action, followed by useful context and a well-structured Args/Returns breakdown. Every section provides relevant information without excessive 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?

For a six-parameter mutation tool with no annotations, the description is complete enough to call correctly: it covers required inputs, optional behavior, modes, selection, and the return dict. The presence of an output schema makes the Returns note a bonus rather than a necessity.

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%, but the description documents all six parameters in the Args section. It adds meaningful semantics beyond the schema, including group creation, weight range, mode behavior, and how selection interacts with omitted vertex_indices.

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 states a specific verb and resource: putting vertices into a vertex group with a weight. It is clear what the tool does, though it does not explicitly distinguish itself from nearby tools such as vertex_group_operation.

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 gives practical usage details for vertex_indices and selection, including that select_* tools should be used first for edit-mode selections. However, it does not explicitly say when to use this tool versus alternatives like vertex_group_operation or remove_vertex_group.

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