list_variables

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

No annotations are provided, so the description carries the transparency burden. It discloses the scope (module-level) and the output details (type and line), which is useful. However, it does not mention potential limitations, such as requiring a loaded project, error behavior, or whether local variables are excluded (only top-level implied). This is moderate transparency for a simple read-only listing 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?

The description is a single, concise sentence that front-loads the main action ('Lists module-level variables') and appends the key output details ('with type and line'). There is no fluff or redundant information, making it highly scannable for an agent.

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?

The tool is simple with one parameter and no output schema. The description covers the core question of what it does and what information it returns. However, it lacks explicit mention of the prerequisite that a project must be loaded (though implied by the parameter description) and does not describe the return structure. Given the low complexity, this is still reasonably complete, but not perfect.

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 description for the 'name' parameter is clear ('Name or path of the loaded project') and covers it fully, so the baseline is 3. The tool description does not add any additional meaning or context about the parameter, such as how it might constrain the results, so it neither improves nor detracts from the schema.

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 lists variables, specifies the scope as 'module-level (top-level)', and mentions the output includes type and line. This distinguishes it from sibling tools like list_functions and list_ts_types, which target different code elements.

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 no explicit guidance on when to use this tool versus alternatives. While the name and description imply it is for listing variables, there is no mention of when to prefer this over related tools like variable_xref or find_unused_variables, nor any exclusions or prerequisites.

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