undo

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

Annotations already declare destructiveHint=true, and the description aligns by indicating an undo action. It adds the return value ('Object with undo description') which provides extra behavioral detail beyond the annotation, though it does not elaborate on side effects or reversibility.

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 extremely concise and front-loaded. It states the purpose in the first sentence and provides the return type in the second, with no wasted words. Perfectly sized for a simple command.

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 no-argument tool, the description is mostly sufficient, but it lacks any mention of the relationship to 'redo' or when undo might be unavailable. The absence of usage guidance and minimal behavioral context makes it slightly incomplete for an agent deciding between undo and redo.

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 tool has zero parameters and the schema covers 100% of them (trivially empty). Per the baseline for 0 params, a score of 4 is appropriate. The description adds nothing about parameters, but none are needed.

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 'Undo the last action in REAPER', which is a specific verb and resource. It distinguishes the tool from its sibling 'redo' by indicating the opposite action, making its purpose unambiguous.

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?

There is no guidance on when to use this tool versus alternatives like 'redo' or 'get_undo_state'. The description only states what it does, without any context on appropriate use cases or exclusions.

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