ivar_set

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

With no annotations provided, the description carries the behavioral disclosure burden. It usefully explains that scalar values are passed as strings and arrays as JSON array strings, which is important encoding behavior. However, it does not mention whether the operation overwrites existing values, requires the variable to already exist, or what side effects or return behavior to expect beyond the set operation.

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 two sentences with no filler. It front-loads the core purpose and immediately provides the most important parameter formatting guidance. Every sentence earns its place.

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 setter with no output schema, the description covers the operation, target level, and value encoding. The only notable gap is the absence of any statement about whether the variable must already exist or whether it is created on demand, but overall the description is sufficiently complete for correct invocation.

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 only 50%, with var_name documented but value lacking any schema description. The description compensates for value by specifying the expected string encoding for scalars and JSON array strings for arrays. This adds meaning beyond the raw schema and helps the agent construct valid values.

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 identifies the operation as setting a system variable (IVar) at Main level. This distinguishes it from sibling setters like dvar_set, svar_set, and mvar_set, and the explicit 'at Main level' scoping removes ambiguity about where the variable is set.

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 provides clear contextual guidance by specifying that this sets an IVar at Main level, which helps an agent select it over other variable setters. It does not explicitly name alternatives or exclusion conditions, but the 'Main level' qualifier gives a clear usage context.

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