mcp_geo_calculate_distance

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It adds valuable context beyond what the schema provides: explains coordinate system conversion ('支持多种坐标系统输入，内部会先转换为WGS84坐标'), describes the calculation method ('通过Web Mercator投影进行平面距离计算'), and specifies applicability ('适用于中小尺度的距离计算'). However, it doesn't mention error conditions, performance characteristics, or what the output looks like.

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?

The description is perfectly concise with three sentences that each add distinct value: states the core function, explains coordinate handling and calculation method, and provides usage context. No wasted words, well-structured, and front-loaded with the main purpose.

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 calculation tool with no annotations and no output schema, the description does reasonably well. It explains the transformation process and applicability scope. However, it doesn't describe the return value format or potential error conditions. Given the 100% schema coverage for inputs and the clear behavioral context provided, this is fairly complete though missing output information.

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 schema already fully documents all 3 parameters. The description doesn't add any parameter-specific information beyond what's in the schema. The baseline of 3 is appropriate when the schema does all the parameter documentation work.

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 description clearly states the tool's purpose: '计算折线的距离' (calculate polyline distance). It specifies the resource (折线/polyline) and the action (计算距离/calculate distance). However, it doesn't explicitly differentiate from its sibling 'mcp_geo_calculate_area' which calculates area rather than distance, though the distinction is implied.

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?

The description provides some usage context: '适用于中小尺度的距离计算' (suitable for small to medium scale distance calculations). This implies when to use it (for appropriate scales) but doesn't explicitly state when NOT to use it or mention alternatives like the sibling tools. No explicit guidance on choosing between this tool and 'mcp_geo_calculate_area' or 'mcp_geo_convert'.

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