blender_bone_shape_assign

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It does state a useful action fact ('Creates (or reuses) a wire mesh shape'), which is some behavior beyond the bare action. But it does not disclose whether an existing custom_shape is overwritten, what happens if the bone or armature does not exist, whether the operation is undoable, or any side effects on the scene.

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, tightly written, and leads with the core purpose. The shape list is useful and not redundant with the schema. It earns its place. Minor inefficiency: the list duplicates the schema enum, but it aids quick comprehension without bloating the text.

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 annotations and no output schema, the description should disclose prerequisites (e.g., armature must exist, bone must exist or be created), error behavior, and whether the shape is reused across calls. None of that is covered. The shape list and scale parameter hint are useful, but an agent is left guessing about failure modes and state changes.

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 the schema already explains every parameter (armature_name, bone_name, shape, scale). The description adds the list of valid shape values, which overlaps with the enum but is still helpful context. With full schema coverage, the baseline of 3 is appropriate.

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 ('Assign'), a specific resource ('custom_shape' on a bone), and the exact purpose ('rig visualization'). It also enumerates the valid shape types, which reinforces what the tool does. It is clearly distinct from sibling tools like blender_constraint_add or blender_armature_create.

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 implies usage context ('for rig visualization') but does not explicitly say when to use this tool versus alternatives, nor does it mention when not to use it. Among the large sibling set, there is no direct alternative for bone custom shapes, so the lack of exclusion is less damaging. However, no explicit guidance is provided.

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