add_bone

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

With no annotations, the description carries the full burden of behavioral disclosure, but it only states the basic mutation ('add a bone') and gives minimal meaning for head and tail. It does not mention whether the armature must be in a particular mode, whether the operation is reversible, error conditions, or any side effects on the armature's bone hierarchy. This is a significant gap for a mutation tool.

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 extremely concise: two short sentences with no filler. The core action is front-loaded. It could be slightly more informative without becoming verbose, but as it stands, every word earns its place, and it is not bloated.

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?

Despite having an output schema, the description is incomplete for a tool with 5 parameters and 0% schema coverage. It fails to specify how to identify the target armature (`object`), how the bone name is used, or how the optional parent bone is referenced. It also omits practical constraints like coordinate space or edit-mode requirements. The agent would need to open the schema and likely still be unsure about parameter semantics and operation context.

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 explains that head and tail are 3D positions, which adds meaning for those two parameters, but it leaves `object`, `name`, and `parent` entirely unexplained. The agent cannot infer from the description what `object` refers to (e.g., the armature object name) or how `parent` should be specified, so the compensation is only partial.

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 bone') and the target resource ('to an armature'), which distinguishes it from siblings like set_bone_property (modifying an existing bone) or add_bone_constraint (adding a constraint). The sentence is specific and unambiguous.

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 offers no guidance on when to use this tool versus alternatives, prerequisites (e.g., the armature must exist or be in edit mode), or context about the parent relationship. Usage is only implied by the verb 'add,' leaving the agent to infer the appropriate situation from the schema alone.

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