MCP Weather Server

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It states the tool returns 'current weather conditions' as a 'formatted string,' which gives some output context. However, it lacks details on error handling, rate limits, authentication needs, data sources, or whether it's a read-only operation, leaving significant gaps for a tool with no annotation support.

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 well-structured and front-loaded, starting with the core purpose. The 'Args' and 'Returns' sections are clear and efficient, with no wasted words. Every sentence adds value, making it easy for an agent to parse quickly.

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?

Given the tool's low complexity (1 parameter) and the presence of an output schema (which handles return values), the description is minimally adequate. It covers the basic purpose and parameter meaning, but with no annotations and incomplete behavioral details, it leaves gaps in transparency and guidelines, making it just viable but not fully helpful.

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?

The schema description coverage is 0%, so the description must compensate. It adds meaningful semantics by explaining the 'city' parameter as 'Name of the city' with examples ('Toronto', 'London', 'Tokyo'), which clarifies usage beyond the bare schema. However, it doesn't address edge cases like city name ambiguities or formatting requirements, preventing a perfect score.

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 the current weather for a city.' It specifies the verb ('Get') and resource ('current weather'), making the action clear. However, it doesn't explicitly differentiate from its sibling 'get_forecast' (which presumably provides future weather predictions), so it doesn't reach the highest score.

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 no guidance on when to use this tool versus alternatives. It doesn't mention the sibling tool 'get_forecast' or clarify that this is for current conditions only. There's no context about prerequisites, limitations, or when not to use it, leaving the agent without usage direction.

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