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

Annotations only declare destructiveHint=true, but the description discloses behavior well beyond that: a partial move splits off a new item with the same sid, a full move relocates the item, a matching destination item triggers a merge, the returned id belongs to the destination, and the operation is reversible by moving back. It also names the underlying endpoint, giving the agent a concrete mental model of a destructive write.

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 with the core action and scope before the edge-case semantics, then closed with a 'WRITE' marker and the endpoint. Dense but essentially waste-free; the merge/sid detail is long yet load-bearing, so it stays below a 5.

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?

Despite having no output schema, the description covers the return-value question (the returned id is the destination's) and the reversible-write path. Combined with 100% schema coverage and a destructiveHint annotation, an agent has everything needed to call this correctly.

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 100% so the baseline is 3, but the description adds real meaning beyond the schema by explaining what 'quantity' actually does (partial move splits a new item vs full move relocates) and what happens when the destination already holds a matching item. The folder_id root-omission and leave_zero_quantity defaults remain schema-only, so it doesn't fully saturate.

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 ('Move some or all of an item's quantity to another folder') and explicitly scopes it to items only, naming the sibling to use for the folder case ('relocate a folder with sortly_update_item parent_id'). An agent can distinguish this from sortly_update_item and the other sortly_* siblings without opening a 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 context for use (moving quantity between folders) and explicitly routes the folder-relocation case to sortly_update_item, plus an undo path ('move it back'). It doesn't spell out prerequisites or a full when-not list, so it falls just short of a 5.

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