Close a Neovim session

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

With no annotations provided, the description carries the full burden. It discloses the termination action, the refusal behavior, and the rationale about user ownership. It could have mentioned potential side effects (e.g., unsaved changes) or irreversibility, but the given context is substantial and non-obvious.

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, front-loaded sentences. The main action is stated first, followed by the key exclusion. Every word earns its place; no filler or redundancy.

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 the tool's simplicity (one parameter, output schema present), the description is complete: it states purpose, scope, exclusions, and rationale. It addresses the sibling tool context by explaining how this differs from attach-related operations.

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 sessionId 100% with a clear description, so the baseline is 3. The description adds behavioral meaning by noting that attach-mode session IDs are rejected, which is crucial semantic information for correctly using the parameter. This elevates the score above the schema-only baseline.

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 uses a specific verb ('Terminate') and clearly identifies the resource ('a Neovim instance this server launched'), immediately distinguishing it from sibling tools like nvim_launch and nvim_attach. It also explicitly contrasts with attach-mode sessions, leaving no ambiguity about scope.

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 explicitly states when to use the tool (for sessions launched by the server) and when not to (refuses attach-mode sessions). It explains why attach sessions are excluded, providing a clear alternative (they are released on server shutdown), which is excellent guidance for an agent.

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