n8n_get_variable

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

With no annotations provided, the description carries the full burden. It discloses the licensing requirement (important behavioral constraint) but fails to confirm if this is read-only, what format the value is returned in, or caching behavior. The license info saves it from a lower score.

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?

Extremely efficient at two sentences. The '[UNIFIED] [Enterprise]' prefixes are metadata noise without context, but the core content is front-loaded and every word serves a purpose. The license requirement is appropriately emphasized.

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 getter with two parameters and no output schema, the description meets minimum viability by identifying the licensing constraint. However, it should describe the return value format (string? object?) and explain the 'site' parameter given the lack of schema documentation.

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 0% - neither 'site' nor 'key' have descriptions. The description mentions 'by key' which loosely hints at the 'key' parameter's purpose, but offers no explanation for 'site' (instance URL? ID? name?). With zero schema coverage, the description fails to adequately compensate for the undocumented parameters.

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?

Clearly states the action (Get) and resource (variable value) with the lookup mechanism (by key). Distinct from sibling operations like create, delete, list, and set. However, it doesn't specify the variable scope (project-level, global, etc.) which would help distinguish from potential alternatives.

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 a critical prerequisite (Requires n8n Enterprise/Pro license) that gates usage. However, it lacks guidance on when to use this versus n8n_list_variables (for browsing) or error handling if the key doesn't exist.

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