spine_update_bone

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

With no annotations, the description carries the full burden and does unusually well: it discloses patch semantics, the cascading rename across children/slots/constraints/skins/animations, subtree re-parenting, cycle refusal, and the color="" clearing convention. It omits permission/auth requirements, persistence or undo behavior, and whether setup-pose edits affect existing animation keys.

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?

Four short sentences, front-loaded with the core action and then per-parameter notes with backticked names. Nothing is redundant and every line adds information an agent would not otherwise have.

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?

An output schema exists, so return values need no explanation, and the mutation semantics are well covered. But for a 15-parameter mutation tool with zero annotation coverage and 0% schema description coverage, leaving most transform parameters and the 'inherit' value domain undocumented is a real gap.

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% across 15 parameters, so the description must compensate and it only explains three of them (new_name, parent, color). The geometry/transform parameters (x, y, rotation, scale_x/y, shear_x/y, length), the string-typed 'inherit' with no documented values, the boolean 'skin', and the required 'project'/'name' pair are left entirely unexplained.

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?

States a specific verb and resource ('Change an existing bone's setup pose'), which cleanly separates it from spine_add_bone and spine_update_slot in the sibling set. It does not explicitly name the sibling it replaces, but 'existing bone' vs 'add_bone' makes the distinction inferable.

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?

Usage is implied by 'existing bone' and by the patch semantics ('Only the arguments you pass are changed'), which tells an agent this is a partial update. There is no explicit when-to-use/when-not guidance, no prerequisites, and no pointer to spine_add_bone for creating bones.

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