Evaluate VimL expression

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

The description focuses on what the tool does (evaluate and return result) but does not disclose potential side effects of executing arbitrary Vimscript, error handling, or whether it is safe/read-only. With no annotations, the description carries full burden but leaves these aspects unaddressed.

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 is front-loaded with the core action and includes a useful example. No redundant information.

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, but lacks an output schema. The description says 'return the result' but does not specify the output format (e.g., string, JSON) or error behavior, which would be helpful for an agent. However, the given example gives some clue about expected output.

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 already covers the parameter ('expr' is described as the Vimscript expression). The description adds an example (`expand('%:p')`) that clarifies expected syntax and return type, providing value beyond 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 evaluates a Vimscript expression and returns the result, with a concrete example (`expand('%:p')`). This distinguishes it from sibling tools like nvim_exec_lua (Lua) and nvim_command (Ex commands).

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 implies usage for Vimscript evaluation, but does not explicitly state when to use it versus alternatives such as nvim_exec_lua or nvim_command. There is no direct comparison or exclusion guidance.

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