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

Annotations already declare it non-read-only, idempotent, and destructive; the description adds substantial context beyond them — a required-confirmation gate, version preconditions, and conflict-recovery policy that no annotation covers. It stops short of explaining what makes the operation destructive (nothing is deleted since every item must appear exactly once), so the destructiveHint is left unaddressed.

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-loads the core action, then presents the constraint, confirmation gate, parameter sourcing, and error policy in dense, waste-free sentences. Every sentence carries a distinct operational instruction.

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?

No output schema exists, and the description compensates by covering the confirmation flow, versioning preconditions, conflict handling, and scope limits — everything an agent needs to invoke this mutation correctly without blindly retrying.

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%, so the baseline is 3. The description restates the orderedItemIds constraint ('every current item ID exactly once, in the new order') and points to library_list_get for listId/expectedVersion, but adds little meaning beyond what the schema already documents per-parameter.

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 (reorder) and resource (items of an owned Library List), and explicitly distinguishes itself from the closest sibling with 'Library Lists only, not trip checklists' — separating it from checklist_items_reorder. An agent can identify the correct tool without opening either 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 explicit preconditions (use listId/expectedVersion from the latest library_list_get), a gated confirmation flow ('show the proposed order first; call with confirmed=true only after they confirm'), and recovery guidance for library_version_mismatch ('read the list again and reconsider; never retry blindly'). It also names the excluded alternative scope.

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