undo

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

With no annotations at all, the description carries the full behavioral burden and falls short. It does not say whether undo is single-level or stack-based, whether the undone action can be restored with redo, what happens when there is nothing to undo, or whether it affects only the agent's own edits or all edits in the workspace.

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?

A single four-word sentence, front-loaded with the verb and free of filler. Its brevity is not the problem; the issue is under-specification rather than wasted wording.

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 state-mutating, zero-parameter tool with no annotations and no output schema, the description should clarify undo depth, reversibility, and the empty-history case. None of that is present, so an agent cannot predict the outcome of calling it.

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 takes zero parameters and the schema is an empty object, so there is no parameter semantics to explain. The baseline of 4 applies since no compensation in the description is required.

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 names a specific verb ('Undo') and a scoped object ('the last action'), so the core operation is understandable. However it never distinguishes this from the sibling 'redo' or from 'clear_all', and 'the last action' is ambiguous about whether the undo history is single-step or multi-step.

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 versus 'redo' (the obvious inverse sibling) or 'clear_all'. The agent is left to infer that this reverses the most recent mutating call, and no preconditions such as 'a prior action must exist' are stated.

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