getWeatherByCityRetrieve weather information by city name for major cities like Beijing, Shanghai, and Wuhan. Specify dates to get forecasts, or omit them to check today and tomorrow's weather.
城市天气查询 - 根据城市名查询天气信息。支持武汉、北京、上海等主要城市。如果不提供日期，默认查询今天和明天的天气数据
| Name | Required | Description | Default |
|---|---|---|---|
| end_date | No | ||
| city_name | Yes | ||
| start_date | No |
Changes observed during successful MCP inspections.
v1.0.1Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden, and it does add one genuinely useful behavioral fact not present in the schema: an omitted date defaults to today plus tomorrow. It says nothing about authentication, rate limits, error behavior, or supported city coverage limits beyond a few examples.
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?
Three compact clauses that front-load the resource and then the scoping/default behavior. No filler or repetition, though it is a single run-on line rather than clearly segmented guidance.
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 tool with no output schema and no annotations, the definition covers the required argument and the date default but omits date format, return-shape expectations, and how city coverage is bounded. Adequate but with clear gaps an agent would have to guess at.
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 0%, so the description must compensate. It explains city_name's role and the default behavior of the date parameters, but never specifies the accepted date string format or whether city names must be Chinese, leaving key invocation details undocumented.
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 states a specific verb and resource ('城市天气查询 - 根据城市名查询天气信息'), and the phrase '根据城市名' implicitly separates it from the sibling getWeatherByLocation. It stops short of explicitly naming that alternative, so it is clear but not fully differentiated.
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?
Usage is only implied: use this when you have a city name. There is no statement of when not to use it and no reference to getWeatherByLocation as the alternative for coordinate/location-based lookups, which is the obvious sibling choice.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.