bpb_place_item

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

With no annotations, the description carries the full burden and does well: it discloses that success returns cells exactly matching the target, that the game's normal placement callbacks fire, that an item may span multiple backpacks, and that the game itself validates position/orientation. The one flaw is the reference to 'outside_bag=true', a flag that does not exist in the input schema, which could mislead an agent looking for it.

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?

One dense paragraph, front-loaded with the purpose then the mechanism, with no filler sentences. The internal implementation steps (pickup → bounding-box center → drop) are arguably more detail than an agent needs, but they are compact and informative rather than wasteful.

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 3-parameter mutation with no annotations and no output schema, the description does cover return semantics and validation responsibility, which is the main gap it needed to fill. It still leaves out failure behavior, what happens to the item's previous slot, and how it relates to sibling placement/edit tools, so it is adequate but not complete.

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 x/y/item_id are already documented with ranges and sourcing (backpack.items, storage, buy_item skill_id), making the baseline 3 appropriate. The description adds behavioral meaning about multi-bag spanning and game-side validation but no new syntax or constraints on the parameters themselves, and the phantom 'outside_bag' reference adds noise rather than clarity.

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?

The opening phrase '原生落格' plus the pickup → set-target → Item.drop() chain makes it clear this places an item into a grid slot using the game's native drop path. It is distinguishable from bpb_place_bag in that it operates on an item, though the description never names that sibling explicitly. The mechanism detail is precise but the one-line purpose statement is somewhat buried in technical steps.

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?

It mentions that '物品/全部模式' allows placing outside the bag, but never says when an agent should choose bpb_place_item over bpb_place_bag, bpb_rotate_item, bpb_edit_items, or bpb_edit_all, nor what preconditions (edit mode open, item in backpack) must hold. There are no explicit exclusions or alternative routing.

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