n8n_create_variable

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It successfully communicates the licensing requirement but fails to disclose idempotency (what happens if the key exists?), return value structure, or persistence guarantees. For a configuration mutation tool, these omissions are significant.

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 efficiently structured in two sentences with no redundant information. The metadata tags '[UNIFIED] [Enterprise]' at the beginning are slightly unconventional but do not significantly detract from the core message. Information is front-loaded effectively.

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 three undocumented parameters (0% schema coverage), no output schema, and no annotations, the description is insufficient. It covers the licensing domain constraint but leaves critical gaps in parameter semantics, error handling scenarios (e.g., duplicate keys), and return value expectations necessary for confident 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?

The input schema has 0% description coverage (no parameter descriptions), and the description fails to compensate by explaining any of the three parameters: 'site' (instance URL? project?), 'key' (variable name?), or 'value'. Without schema documentation or description context, the agent cannot correctly interpret the 'site' parameter's expected format.

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 the specific action ('Create') and resource ('environment variable'), distinguishing it from sibling operations like update_variable, delete_variable, and list_variables. The inclusion of 'new' further clarifies this is for initial creation rather than modification.

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 a critical prerequisite ('Requires n8n Enterprise/Pro license') which constrains when the tool can be used. However, it lacks explicit guidance on choosing between this and n8n_set_variables (likely for bulk operations) or distinguishing creation from updating existing variables.

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