n8n: Get variable

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

readOnlyHint=true already declares this as a safe read, so the bar is low, but the description does add a genuinely useful constraint: an Enterprise/Pro license is required. It does not disclose what happens on a missing key (error vs. empty) or how the value is surfaced, which are the remaining behavioral questions for a lookup tool.

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?

Two short sentences with the action and the license prerequisite front-loaded. The bracketed "[UNIFIED]" tag adds no meaning for an agent and is the only wasted token.

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 read with no output schema, an agent needs the purpose, the license gate, and enough on each parameter to call it. Purpose and license are covered, but the undocumented `site` parameter and the unstated not-found behavior leave real gaps.

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% and there are two required parameters. The description explains only one of them ("by key"); the required `site` parameter is never mentioned in the description or the schema, leaving the agent to guess what it means or what value to supply.

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?

States a specific verb and resource ("Get variable value by key") that clearly separates it from the create/update/delete variable siblings implied by the naming. The remaining ambiguity is only what a "variable" contains, which the name largely conveys.

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?

No guidance on when to use this versus alternatives, no mention of what to do when the key does not exist, and no prerequisites beyond the license note. Usage is only implied by the verb.

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