add_rigvm_node

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

Annotations declare a non-read-only, non-destructive, non-idempotent mutation, so the safety profile is already covered. The description contributes the return contract (saved, already_exists, save_error), which hints that the node is written to disk and that a pre-existing node is tolerated, but it never states that the operation persists/saves the asset or repeats the PIE hazard, so the disclosure stays partial.

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 purpose is front-loaded in a single unadorned sentence followed by a return-type block, with no filler or marketing language. The return block is a dense flat list rather than prose, but given there is no output schema it earns its space.

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 5-parameter mutation tool with annotations and no output schema, the description covers purpose and return shape, which is the main gap an agent would otherwise face. It omits operational detail such as whether the asset is saved to disk, whether the node is immediately connectable, and the PIE refusal, leaving some inference to the schema.

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 100%, so the schema already documents control_rig_path, node_type (with the six valid values), node_name, position, and force's PIE caveat. The description adds no parameter-level meaning of its own beyond echoing 'node_type' in the return list, making 3 the correct baseline.

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+resource pair: 'Add a rig-unit node to a Control Rig's RigVM solver graph', which is concrete enough for an agent to distinguish it from neighbors like add_rigvm_link, remove_rigvm_node, or add_anim_graph_node. It does not, however, explicitly name or contrast any sibling tool, so it stops short of a 5.

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?

There is no when-to-use guidance, no prerequisite statement, and no mention of alternatives (e.g., 'use add_rigvm_link to wire it up afterward', or 'use get_rigvm_graph to inspect first'). The only contextual limitation, the Play-in-Editor refusal, lives in the schema's force parameter rather than in the description.

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