create_variable

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

Annotations already indicate this is write-only (readOnlyHint=false) and not destructive. The description adds value by revealing that the variable starts empty, which informs the agent about the initial state and the need for subsequent steps.

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 purpose and types, then follow-up actions and return value. No redundant words, every sentence is essential.

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?

Given the complexity and sibling tools, the description fully explains the lifecycle (create, set values, bind) and mentions the return shape. No gaps for the agent to infer.

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 coverage is 100% with inline descriptions for all three parameters. The description provides an example for name ('color/primary') and reiterates the enum values, adding helpful context beyond the schema.

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 uses the specific verb 'Create' and clearly states the object: 'a variable in a collection'. It specifies the allowed types and distinguishes from sibling tools like set_variable_value and bind_variable_to_node by outlining the workflow.

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?

Provides explicit step-by-step guidance: after creation, set values with set_variable_value, then attach with bind_variable_to_node or bind_variable_to_paint. This tells the agent exactly when to use this tool and what to do next.

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