list_variables

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

The annotation readOnlyHint already signals a safe read operation, and the description's 'List' aligns with that. However, the description adds no behavioral context beyond the annotation—such as pagination, ordering, or response format. It merely restates the tool's name in sentence form, providing minimal additional transparency.

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 single, front-loaded sentence with no wasted words. It immediately states the action and the resource, making it highly concise and scannable. No unnecessary details or fluff.

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 read-only listing tool with two optional parameters, the description is reasonably complete. However, there is no output schema, and the description doesn't mention expected response structure or pagination behavior, which could leave the agent uncertain about what to expect. It's adequate but not rich.

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 schema describes both parameters (limit and cursor) with meaningful descriptions, achieving 100% coverage. The description itself adds no extra parameter-level information, so a baseline score of 3 is appropriate. It doesn't need to compensate for missing schema details.

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 tool's function: 'List n8n environment/instance variables.' The verb 'List' and the specific resource 'n8n environment/instance variables' distinguish it from sibling list tools such as list_workflows and list_credentials. No ambiguity about what the tool does.

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 doesn't provide explicit guidance on when to use this tool versus alternatives. It is the only tool for listing variables, so usage is implied, but there's no mention of pagination behavior or when to use the 'cursor' parameter. The use case is clear but not elaborated.

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