Open-Meteo MCP 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. While it mentions the API source (Open-Meteo) and data types (hourly/daily), it lacks critical behavioral information: whether this is a read-only operation, what authentication might be required, rate limits, error conditions, response format, or whether it makes external API calls. For a tool with 11 parameters and no output schema, this leaves significant gaps in understanding how the tool behaves.

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 appropriately concise with two sentences that efficiently convey the core functionality. The first sentence states the primary purpose, and the second adds key capability information. There's no wasted language or redundancy. However, it could be slightly more front-loaded with distinguishing information given the many sibling tools.

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 complexity (11 parameters, no annotations, no output schema, 16 sibling tools), the description is insufficiently complete. It doesn't explain what the tool returns (no output schema exists), doesn't help distinguish it from alternatives, and provides minimal behavioral context. For a data retrieval tool with many configuration options and similar alternatives, the description should do more to guide proper use and set expectations.

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 documents all 11 parameters thoroughly with descriptions, enums, defaults, and constraints. The description adds minimal value beyond the schema - it mentions 'hourly and daily data with various weather variables' which corresponds to two parameters, but doesn't provide additional context about parameter interactions, dependencies, or usage patterns. This meets the baseline expectation when schema coverage is complete.

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 data for coordinates using Open-Meteo API.' It specifies the verb ('Get'), resource ('weather forecast data'), and scope ('for coordinates'), which is specific and actionable. However, it doesn't explicitly differentiate this tool from its many siblings (like 'gfs_forecast', 'ecmwf_forecast', etc.), which all appear to be weather-related tools on the same server.

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. With 16 sibling tools on the server (including 'gfs_forecast', 'ecmwf_forecast', 'air_quality', etc.), the agent receives no help in selecting this specific Open-Meteo-based forecast tool over other weather data sources. The mention of 'Supports hourly and daily data with various weather variables' describes capability but not selection criteria.

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