Creates a system variable (IVar) at the Main level in IC-CAP from just a variable name. Supply an initial value to define it for use in measurements and transforms.
Create a system variable (IVar) at Main level. var_name is the variable name only (no path prefix).
| Name | Required | Description | Default |
|---|---|---|---|
| value | No | Initial value | |
| var_name | Yes | Variable name only (no path), e.g. 'MY_VAR' |
Changes observed during successful MCP inspections.
v0.2.2Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations available, the description carries the full burden of behavioral disclosure. It clearly states the core behavior and location, but it does not mention side effects such as whether an existing variable is overwritten, whether creation fails if a variable already exists, or any required parent context beyond 'Main level'. The naming constraint adds useful behavior beyond the tool name.
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 description is a single, focused sentence with no redundant words. The primary action and scope are front-loaded, and the naming warning is placed where it directly supports correct invocation.
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 simple two-parameter create tool with no output schema, the description covers the essential information: what is created, where it is created, and how parameters should be named. A small gap is the lack of any statement about collision behavior or return value, but the tool is simple enough that the description is nearly complete.
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 baseline is 3. The description repeats the var_name restriction already present in the schema, such as 'variable name only (no path prefix)', but adds no new parameter-level meaning. It does not explain value handling or default behavior beyond what the schema already provides.
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 clearly states a specific action, 'Create a system variable (IVar)', and the target scope, 'at Main level', which distinguishes it from sibling create tools like svar_create or dvar_create. It also clarifies the naming restriction, leaving no ambiguity about what resource is being acted on.
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 description implies usage context by specifying that this creates a Main-level IVar, but it does not explicitly contrast this with alternatives such as svar_create or dvar_create. It gives enough context for an agent to infer the intended use, but it does not provide explicit when-to-use or when-not-to-use guidance.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.