rigify_add_face_rig

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

No annotations are provided, so the description must disclose behavioral traits. It only states 'Add or configure', implying non-destructive modification, but omits details on prerequisites (e.g., must be in edit mode), whether changes are reversible, or response behavior.

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 sentences plus parameter list. The primary function and use case are front-loaded, with no unnecessary information.

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?

The description covers the basic purpose and parameters, and an output schema exists so return values are not needed. However, behavioral details like mode requirements or side effects are missing, which reduces completeness for a tool that modifies an armature.

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 adds significant meaning: metarig_name is explained as name of the meta-rig armature, and detail_level enumerates values: 'full', 'basic', 'eyes_only' with clarifications. This compensates well for the schema's lack of 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 adds or configures face rig bones on a Rigify meta-rig. It uses a specific verb ('Add or configure') and resource ('face rig bones on a Rigify meta-rig'), and distinguishes it from siblings like rigify_create_metarig which creates the entire meta-rig.

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 provides clear context: 'Useful when the meta-rig was created without face bones, or to adjust face rig detail.' It indicates when to use but does not explicitly mention when not to use or name alternatives among siblings.

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