Creates a bone chain along a polyline of world points, connecting each point to the next. Use it to rig limbs, spines, tails, or tentacles.
Bones along a polyline of world points (n points → n-1 bones, each reaching the next point). Use for limbs, spines, tails, tentacles.
| Name | Required | Description | Default |
|---|---|---|---|
| name | Yes | ||
| parent | No | root | |
| points | Yes | ||
| project | Yes |
Changes observed during successful MCP inspections.
v0.2.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It usefully discloses the structural behavior (n points produce n-1 bones, each reaching the next), but says nothing about side effects, permissions, whether an existing rig is modified, or what is returned. Adequate but incomplete for a mutation tool with zero annotation coverage.
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?
Two sentences, front-loaded with the defining mechanic and followed by usage examples. Every clause earns its place with no redundancy.
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, no output schema, and 0% parameter coverage, the description conveys the core concept but omits parameter meanings and behavioral side effects. It is minimally sufficient to understand intent but not to invoke confidently.
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 4 parameters, so the description must compensate. It clarifies that 'points' are world-space polyline coordinates, which is a genuine semantic addition, but leaves 'name', 'parent' (including its default of root), and 'project' entirely undocumented.
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 ('Bones along a polyline of world points') and explains the mechanics (n points → n-1 bones, each reaching the next point). This implicitly distinguishes it from the sibling add_bones, but it never names that alternative explicitly, so it falls short of full sibling differentiation.
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?
'Use for limbs, spines, tails, tentacles' gives clear positive use-case context. However, it offers no exclusions or named alternatives (e.g. when to prefer add_bones or rig_serpent over a manual chain), so it stays at clear-context-without-exclusions.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.