Rotate a single SO-101 robot joint by a relative degree offset, applying the move only when the resulting position stays within configured safety limits.
Rotate a single joint by a relative amount from its current position. Example: joint="shoulder_pan", delta_degrees=-10 (negative pan = left). The final position must be inside the limits in config.json, otherwise nothing moves.
| Name | Required | Description | Default |
|---|---|---|---|
| joint | Yes | ||
| delta_degrees | Yes |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already flag this as destructive and non-idempotent, so the bar is lower, and the description still adds real value: the move is silently rejected if the target falls outside the limits in config.json, which is critical pre-call knowledge. It does not say what happens to prior state or how a rejected move is reported, but the key failure mode is disclosed.
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?
Three short sentences: the core behavior first, then a concrete example, then the failure constraint. No filler, and the most important information is front-loaded.
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 two-parameter tool with no output schema, the description covers purpose, an example, and the limits-based rejection behavior, which is enough to invoke it. The main omission is the set of valid joint identifiers, which an agent would otherwise have to discover by trial.
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 carry the burden; it does supply a concrete joint value ("shoulder_pan") and the sign convention (negative pan = left), which is genuinely beyond the schema. However, it never enumerates valid joint names or clarifies units beyond the parameter name itself, leaving real gaps.
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?
Names a specific verb (rotate) and a precisely scoped resource (a single joint) and states that the motion is relative from the current position, which implicitly contrasts with the plural move_joints sibling. It stops short of naming the alternative tool, so the differentiation is inferred rather than stated.
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 example clarifies the intent of a relative move, but there is no explicit guidance on when to pick this over move_joints, move_to_pose, or get_robot_state first, nor any prerequisite such as needing the robot in a known state. Usage is implied rather than directed.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.