set_variable

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

With no annotations, the description carries the full behavioral disclosure burden. It does reveal a meaningful side effect ('and rebuild') and the create flag's effect ('enables new user variables'), which go beyond the schema. However, it does not disclose whether existing values are overwritten, how value and expression interact, or what happens when value is null. Partial disclosure, not a contradiction.

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 compact two-sentence structure with the core operation front-loaded: 'Set one numeric value OR native expression and rebuild.' Every sentence adds useful information, and there is no filler. Slightly more detail could be added without harming conciseness, but as written it is efficient.

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 seven parameters, no annotations, and no output schema, the description is too thin to fully equip an agent. It does not explain the required document_id/name roles, the purpose of feature_id, or the mutual-exclusivity handling of value vs expression. The agent would likely need to open schemas or guess to invoke correctly in varied scenarios.

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 compensate. It adds meaning to value ('numeric'), expression ('native expression'), and create ('enables new user variables'), but says nothing about document_id, name, note, or feature_id. Seven parameters exist, and at least four receive no semantic explanation in the description or 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 names a clear verb ('Set'), a resource ('variable'), and adds scope ('one numeric value OR native expression', 'rebuild'). It is distinguishable from sibling tools like list_variables (read vs write) and create_feature (features vs variables). It loses one point because 'rebuild' is left vague and the description does not explicitly contrast with list_variables.

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 explicit guidance on when to use this tool instead of a sibling. The phrase 'Explicit create enables new user variables' implies a condition for creating vs updating, but it does not say when to prefer set_variable over list_variables or other mutation tools. No exclusions or alternative-routing are provided.

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