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

Annotations declare non-readonly, non-idempotent, non-destructive, and the description adds two behavioral facts those hints don't convey: failure instead of silent no-op at the tail, and redo-tail truncation when a new op is applied after an undo. It stops short of describing what the replayed op returns or how state changes are surfaced, so it's strong but not exhaustive.

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 sentences, front-loaded with the core action and followed by the failure mode and the truncation caveat; each sentence carries distinct information. The 'Note:' framing is slightly ceremonial but the content is not padding.

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?

Covers purpose, failure behavior, and the stack-truncation side effect for a small two-param mutation tool with no output schema. The one real gap is return behavior (what the replayed op yields / resulting cursor state), which no structured field documents and the description omits.

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 coverage is 50%: `rationale` is fully documented in the schema, while `map_id` carries no description in either place. The description never clarifies map_id's role or how it relates to the cursor/ops-log model, so it adds little semantic value over the structured fields.

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 mechanism ('advance the workspace cursor by one toward the tail of the ops log, replaying the next op that was previously undone'). This is immediately distinguishable from the sibling `undo`, which moves the opposite direction, so an agent can select correctly without opening the 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?

Gives clear usage context: call it to re-apply an undone op, and it fails when the cursor is already at the tail. The counterpart tool (`undo`) is implied by 'previously undone' but never named explicitly, so the when-to-use-vs-alternative routing is clear-but-not-explicit rather than fully spelled out.

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