list_variables

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

No annotations provided, so the description must cover behavior. It states the tool lists variables (read-only), but doesn't disclose potential performance implications, pagination behavior beyond the max_results parameter, or whether the list is exhaustive. The filter behavior is well explained.

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 concise sentences. The first sentence front-loads the core purpose and returned fields. The second adds specific filter detail. No unnecessary words.

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 listing tool with no output schema, the description is adequate. It lists the returned fields and filter behavior. Sibling tools are mainly mutation tools, so purpose is clear. Could mention that it returns only top-level (non-array/nested) variables, but global scope is already stated.

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%, so the description must compensate. It explicitly explains name_filter's substring matching behavior, adding value. However, max_results is not mentioned, leaving the agent to infer its purpose from the default value and name. Missing explanation of max_results limits completeness.

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 'List global variables' with specific fields (type, comment, address, initial value). This distinguishes from sibling tools like create_variable, update_variable, etc., which are mutation tools.

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?

Describes name_filter's case-insensitive substring match, giving clear guidance on when to use the filter. However, no explicit when-not or alternatives are mentioned, and there's no mention of other filtering or sorting options.

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