US Government Open Data MCP

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 'Get observations,' implying a read-only operation, but does not clarify if it requires authentication, has rate limits, returns paginated results, or what the output format looks like. For a data retrieval tool with zero annotation coverage, this leaves significant gaps in understanding its behavior.

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 concise and front-loaded with the core purpose in the first sentence. The second sentence provides useful examples without unnecessary elaboration. However, it could be slightly improved by integrating the examples more seamlessly or adding a brief note on usage context.

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 complexity (6 parameters, 1 required) and lack of annotations and output schema, the description is minimally adequate. It states what the tool does and gives examples, but fails to address behavioral aspects like response format, error handling, or authentication needs. For a data retrieval tool in a server with many siblings, more context would enhance completeness.

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%, meaning all parameters are documented in the input schema. The description does not add any parameter-specific details beyond what the schema provides (e.g., it doesn't explain the meaning of 'frequency' values like 'd, w, bw' or default behaviors). With high schema coverage, the baseline score of 3 is appropriate as the description adds no extra semantic value.

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 observations for a FRED series.' It specifies the verb ('Get') and resource ('observations for a FRED series'), making the action explicit. However, it does not distinguish this tool from its sibling 'fred_search' or 'fred_series_info', which might offer related functionality, so it misses full sibling differentiation.

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 implied usage through examples ('Popular: GDP, UNRATE, CPIAUCSL, FEDFUNDS, DGS10, MORTGAGE30US'), suggesting common series IDs to use. However, it lacks explicit guidance on when to choose this tool over alternatives like 'fred_search' or 'fred_series_info', and does not mention any prerequisites or exclusions for usage.

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