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es3154

Turf-MCP

by es3154

measurement_length

Calculate the spherical length of GeoJSON LineString or MultiLineString geometries, accounting for Earth's curvature, with configurable distance units.

Instructions

计算线或多线的长度。

此功能计算给定线或多线几何图形的实际长度,考虑地球曲率,返回指定单位的长度值。

Args: geojson: GeoJSON 线或多线对象 - 类型: str (JSON 字符串格式的 GeoJSON) - 格式: 必须符合 GeoJSON LineString 或 MultiLineString 规范 - 坐标系: WGS84 (经度在前,纬度在后) - 示例: '{"type": "LineString", "coordinates": [[-74, 40], [-78, 42], [-82, 35]]}'

options: 可选参数配置
    - 类型: str (JSON 字符串) 或 None
    - 可选字段:
        - units: 距离单位 (默认: 'kilometers')
            - 有效值: 'miles', 'nauticalmiles', 'kilometers', 'meters', 'yards', 'feet', 'inches'
    - 示例: '{"units": "miles"}'

Returns: str: JSON 字符串格式的长度结果对象 - 类型: 包含 value 和 units 的对象 - 格式: {"value": 长度数值, "units": "距离单位"} - 示例: '{"value": 123.45, "units": "miles"}'

Raises: Exception: 当 JavaScript 执行失败、超时或输入数据格式错误时抛出异常

Example: >>> import asyncio >>> line = '{"type": "LineString", "coordinates": [[-74, 40], [-78, 42], [-82, 35]]}' >>> options = '{"units": "miles"}' >>> result = asyncio.run(length(line, options)) >>> print(result) '123.45'

Notes: - 输入参数 geojson 和 options 必须是有效的 JSON 字符串 - 坐标顺序为 [经度, 纬度] (WGS84 坐标系) - 计算的是线或多线的球面长度 - 依赖于 Turf.js 库和 Node.js 环境

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
geojsonYes
optionsNo

Output Schema

TableJSON Schema
NameRequiredDescriptionDefault
resultYes
Behavior4/5

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

With no annotations provided, the description carries full burden and does well by disclosing key behaviors: it returns a JSON string with value and units, raises exceptions for failures/timeouts/input errors, depends on Turf.js and Node.js, and calculates spherical lengths. It could improve by mentioning performance or rate limits, but covers essential operational aspects.

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?

The description is well-structured with clear sections (Args, Returns, Raises, Example, Notes) and front-loaded purpose. It's appropriately sized but could be slightly more concise by integrating some Notes into Args or reducing repetition in examples. Every sentence adds value, though minor trimming is possible.

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

Completeness5/5

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

Given the tool's moderate complexity (2 parameters, no annotations, but with output schema), the description is highly complete. It covers purpose, parameters, return format, errors, dependencies, and examples. The output schema exists, so the description correctly doesn't re-explain return values, focusing instead on usage context and input details.

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

Parameters5/5

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

Schema description coverage is 0%, so the description must compensate fully. It provides detailed semantics for both parameters: 'geojson' is explained with type, format, coordinate system, and an example; 'options' is detailed with type, optional fields, valid units, default, and an example. This adds significant value beyond the bare schema.

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?

The description clearly states the specific action ('计算线或多线的长度' - calculates length of lines or multilines) and resource ('线或多线几何图形' - line or multiline geometries). It distinguishes from sibling tools like 'measurement_distance' (which measures distance between points) and 'measurement_area' (which calculates area), establishing a unique purpose within the measurement category.

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

Usage Guidelines3/5

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

The description implies usage context by specifying it calculates '实际长度, 考虑地球曲率' (actual length, considering Earth's curvature), suggesting it's for geospatial applications. However, it lacks explicit guidance on when to use this tool versus alternatives like 'unit_conversion_convertLength' (which converts length units) or 'measurement_distance' (which measures point-to-point distance), leaving some ambiguity.

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

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