undo

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

Goes well beyond the annotations (destructiveHint=true, readOnlyHint=false) by exposing a non-obvious trap: 'success is ALWAYS true, including when there was nothing to undo', and naming `applied` as the real oracle with re-reading as honest verification. This is exactly the kind of failure-mode disclosure annotations cannot carry.

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?

Front-loaded: the action, the critical warning, the alternatives, and the return shape all appear in order with little padding. Slightly dense in the warning clause, but every sentence earns its place.

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?

With no output schema available, the description compensates by spelling out the full return object and flagging which field is authoritative. For a zero-parameter mutation tool, nothing an agent needs to call it correctly is missing.

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 the baseline is 4. The description instead documents the return contract (applied, undo_count, can_undo, next_undo), which is useful but belongs to output rather than parameter semantics.

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 and resource ('Step the editor's undo stack back by one transaction') with exact scope ('by one transaction'), which cleanly distinguishes it from undo_multiple and get_undo_state. An agent can identify the tool's action without opening any schema.

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?

Explicitly routes to alternatives: 'Use undo_multiple for N steps and get_undo_state to look before you leap.' It also names a stopping condition ('an undo barrier will stop it'), so both the when and the when-not are covered.

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