undo

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

With no annotations, the description carries the full burden, and it does disclose the underlying mechanism (ChangeHistoryService), implying the operation is session-scoped and only affects editor-tracked changes. However, it says nothing about failure modes, whether the undo is reversible via redo, or whether it interleaves with other agents' changes.

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 front-loaded sentence with no filler; the action and its scope appear in the first three words. It is efficient, though the brevity leaves open questions that the definition never returns to address.

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 zero-parameter, no-output-schema tool this is nearly sufficient, but the absence of annotations and of any note on empty-history behavior or the undo/redo pairing leaves a small but real gap. Adequate rather than complete.

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, so there is nothing for the description to disambiguate; baseline 4 applies. The parenthetical service reference is consistent with a no-argument operation.

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?

States a specific verb (undo) and resource (last Studio change), and names the underlying mechanism (ChangeHistoryService), which scopes it to editor history rather than file or network state. It does not explicitly differentiate itself from its natural sibling 'redo', leaving the agent to infer the pairing.

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?

No when-to-use guidance, no mention of the complementary 'redo' tool, and no conditions stated (e.g., behavior when the change history is empty or when a playtest is running). The agent must infer that this applies only after a mutating operation in the current Studio session.

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