MCP Weather Server

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

With no annotations provided, the description carries full burden for behavioral disclosure. It mentions the tool 'Returns weather forecast for the next few days' which gives some output information, but doesn't describe error conditions, rate limits, authentication requirements, or what happens when location isn't provided (though the schema covers this). More behavioral context would be helpful for a tool with no annotations.

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 extremely concise with just two sentences that directly state the tool's purpose and what it returns. Every word earns its place with no redundancy or unnecessary elaboration.

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 tool with 2 parameters, 100% schema coverage, but no annotations and no output schema, the description provides basic purpose but lacks guidance on sibling tool differentiation and behavioral context. It's minimally adequate but has clear gaps in usage guidance and behavioral transparency that would help an agent use it correctly.

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 fully documents both parameters. The description doesn't add any parameter semantics beyond what's in the schema - it mentions 'location' and 'forecast for the next few days' but these are already covered. 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: 'Get weather forecast for a location' with the verb 'Get' and resource 'weather forecast'. It distinguishes from 'getHourlyWeather' by specifying 'for the next few days' rather than hourly, but doesn't explicitly differentiate from 'getWeather' or 'lookupCity'.

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?

No guidance is provided about when to use this tool versus the sibling tools 'getHourlyWeather', 'getWeather', or 'lookupCity'. The description mentions 'Returns weather forecast for the next few days' which implies a multi-day forecast, but doesn't explicitly state this is for daily forecasts versus hourly or current weather.

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