Copernicus Earth Observation MCP Server

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

With no annotations provided, the description carries the full burden and adds significant behavioral context: it discloses authentication requirements (environment variables), performance characteristics ('can take hours'), and a testing recommendation. It does not cover aspects like error handling or output format, but provides more than minimal disclosure.

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 front-loaded with the core purpose, followed by critical prerequisites and warnings. Every sentence adds value: the first states the action, the second covers authentication, and the third provides usage guidance. No wasted words, and structure prioritizes essential information.

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 4 parameters with 0% schema coverage and no annotations, the description does well by covering authentication, performance, and key parameter usage. With an output schema present, return values need not be explained. It could improve by mentioning 'mission' or 'output_dir', but it's largely complete for a download tool.

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 0%, so the description must compensate. It explains the purpose of 'download_type' (with values 'full' and 'quicklook') and implies 'image_id' is required, adding meaning beyond the bare schema. It does not detail 'mission' or 'output_dir', but provides enough context for core functionality.

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 specific action ('Download') and resource ('Copernicus satellite image by ID'), distinguishing it from siblings like 'get_image_details' (metadata) or 'search_and_download' (search-based). It directly answers what the tool does without ambiguity.

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 explicit context for when to use this tool: for downloading by ID, with a warning about time and a suggestion for testing. However, it does not explicitly state when to use alternatives like 'batch_download_images' for multiple images or 'search_and_download' for search-based downloads, leaving some sibling differentiation implicit.

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