create-variable

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

No annotations exist, so the description carries the burden. It discloses the license requirement but fails to mention behavioral details like side effects (e.g., overwriting existing keys), authorization scopes, or mutation consequences. The description is too brief for a write operation.

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: main action first, then value proposition, then important notes. It is concise without being wasteful. The note about JSON formatting is essential and placed appropriately.

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 no output schema and low parameter complexity, the description covers the core purpose and a key constraint (license). However, it omits what the tool returns (if anything) and any error or duplicate behavior, leaving the agent slightly underinformed.

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 100%, so the schema already describes all three parameters. The description adds the input format requirement (single-line JSON) but does not enrich the meaning of individual parameters (key, value, clientId). Baseline 3 is appropriate.

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 creates a new variable in n8n and adds context that variables can be used across workflows. It distinguishes from sibling tools like delete-variable or list-variables by focusing on creation. However, it does not further elaborate on the scope or uniqueness.

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 (Enterprise license required) and a specific input format requirement (compact, single-line JSON). However, it does not compare to alternatives or indicate when not to use this tool (e.g., when to use update-variable or other creation tools).

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