Skip to main content
Glama
Sign In
Backpack Battles MCP

Backpack Battles MCP

by 53721222-gif
OverviewSchemaSourceRelated ServersDiscussionsAdmin
Local

bpb_rotate_bag

Rotates an empty backpack left or right by atomically removing, reorienting, and re-adding the item, and reports bag_not_empty when the backpack is not empty.

Instructions

游戏内原子旋转空背包（已启用）：目标格全在包内且无重叠时，removeItem → orientItem → addItemByTopLeft；非空背包返回 bag_not_empty。BPB_ROTATE=0 可关闭。

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "item_id": "<item_id>"
    },
    "name": "bpb_rotate_bag"
  }
}

Input Schema

NameRequiredDescriptionDefault
item_idYes
directionNoright

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observedv0.1.0

TDQS

A3.9/5.0
Behavior4/5

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

With no annotations, the description carries the burden and does well: it discloses the atomic implementation order (removeItem → orientItem → addItemByTopLeft), the placement constraints (all target cells in-bag, no overlap), the failure mode (bag_not_empty), and the feature-flag gate. It leaves the return payload and whether direction affects the sequence unstated.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

One dense semicolon-delimited sentence with the verb+resource front-loaded and no filler; the compression into a single line makes it slightly harder to scan but every clause carries information.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a mutation with no annotations, no output schema, and fully undocumented parameters, the behavior/failure coverage is good but the description still leaves an agent guessing at the id semantics and at what is returned on success.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters2/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0% and two parameters exist, but the description never explains what item_id refers to (presumably the bag's item id) or what direction right/left means for the rotation. The schema-side enum is self-evident, but the required id parameter is undocumented anywhere.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource (atomic rotation of an empty backpack) scoped by the 'empty' precondition, which inherently separates it from bpb_rotate_item (rotates an item) and bpb_place_bag.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly sets the usage precondition — only for empty backpacks, non-empty ones return bag_not_empty — and notes the feature flag (BPB_ROTATE=0 disables). It stops short of naming an alternative tool to use when the bag is non-empty or when rotating an item instead.

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

Deploy Server

Other Tools