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

Annotations already declare destructiveHint=true and non-idempotency, so the risk profile is known. The description adds value beyond them by disclosing the single-level undo depth ("One step only") and the required authorization scope (pipelines:write), which annotations do not express. It does not describe the failure mode when nothing is undoable, keeping it just under top marks.

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?

Three short sentences that are front-loaded with the core action, followed by the depth limit, the trigger, and the scope requirement. No sentence is redundant or restates a structured field verbatim.

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 single-parameter mutation tool with an output schema absent but annotations rich, the description supplies the action, depth limit, trigger, and auth scope. The only meaningful omission is the no-op/error behavior when there is no previous edit to revert.

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?

There is only one parameter and schema coverage is 100%, with the schema itself explaining where projectId comes from (list_projects or open_run_in_timeline). The description adds no further parameter detail, which is acceptable given the schema already carries that burden.

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?

Names a specific verb and resource ("Put a timeline project back the way it was before the last edit_project") and explicitly contrasts itself with the sibling edit_project, so an agent can pick it without inspecting either schema. The "One step only" clause also bounds the scope of the operation.

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?

Gives a concrete triggering condition ("the moment the person says the change was wrong") and names the wrong alternative to avoid ("reversing it by hand with more edits"). It stops short of stating what happens when there is no prior edit to undo, so it is clear context rather than full when/when-not coverage.

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