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

Annotations already declare this is a non-read-only, non-destructive, closed-world operation, and the description adds nothing beyond that. For a mutation tool it fails to say whether the undo is itself undoable via redo, whose last change is undone, or whether the history is per-project — all behaviorally important.

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 or repetition, which is structurally efficient. Its brevity is nearly under-specification, but as a conciseness measure it is sound.

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?

An output schema exists, so return values need no explanation. However, for a mutation tool with redo/snapshot siblings, the description omits the undo scope, preconditions, and reversibility, leaving material gaps.

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?

Schema description coverage is 100% and the single project_id parameter is fully documented as a Project UUID, so the schema carries the semantics. The description adds no scope detail (e.g., which change history is keyed by that ID), matching the baseline-3 case.

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 project change), identifying the operation clearly. It doesn't name the obvious counterpart projects_redo or clarify whether the undo is scoped to the project or the caller's own last action, so sibling differentiation is only implicit.

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 at all: nothing explains how this differs from projects_redo, projects_patch, or restore_project_snapshot, nor what precondition (an existing change history) must hold. The agent must infer the usage context from the name alone.

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