mujoco_close_session

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

The description adds meaningful side-effect details beyond the annotations: it frees model and data, invalidates the session_id, and returns a JSON shape with remaining sessions. This is consistent with destructiveHint=true and idempotentHint=false, with no contradiction.

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 compact and well-structured: action and consequence first, invalidation note second, return format third. Every sentence contributes useful information without repetition.

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 single-parameter destructive cleanup tool, this description covers the action, side effects, and return shape sufficiently. The explicit JSON return format is especially helpful since the output schema is not fully available in context.

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?

With 0% schema description coverage, the description must compensate for the session_id parameter. It does show the parameter in context and states it becomes invalid, which adds some meaning, but it does not explain where a valid session_id comes from or its expected format. The single-parameter context makes this moderate rather than severe.

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 opens with a specific verb and object: 'Close a session and free its model and data.' It clearly distinguishes this from close_viewer and session-listing tools by focusing on session lifetime and resource cleanup.

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 intended use is clear: close a session to release its model and data, with the warning that the session_id becomes invalid immediately. It does not explicitly name an alternative or exclusion, but the object and effect are unambiguous enough to guide selection among siblings.

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