US Government Open Data MCP

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

Annotations provide readOnlyHint=true, indicating a safe read operation. The description adds valuable context by specifying the types of breakdowns returned ('recruiting, active, completed, or terminated') and the dual search capability for conditions and drugs, which goes beyond what annotations alone convey. No contradictions with annotations exist.

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 in the first sentence, followed by clarifying details in subsequent sentences. Every sentence adds value without redundancy, making it efficient and easy to parse.

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 moderate complexity (2 parameters, read-only operation), the description is largely complete. It explains what the tool does, when to use it, and provides examples. However, without an output schema, it doesn't detail the structure of returned breakdowns (e.g., format of counts), leaving a minor gap.

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 adds minimal semantic context by mentioning examples ('breast cancer', 'semaglutide') and the purpose of 'search_as_drug', but doesn't provide additional syntax or format details beyond the schema. This meets the baseline for high schema coverage.

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 with specific verbs ('Get trial count breakdown') and resources ('by status for a condition or drug/intervention'). It distinguishes itself from sibling tools like 'clinical_trials_detail' and 'clinical_trials_search' by focusing on statistical breakdowns rather than detailed records or search functionality.

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 usage guidance by stating it 'Works for diseases ('breast cancer') AND drug names ('semaglutide', 'pembrolizumab')' and implies when to use the 'search_as_drug' parameter. This helps differentiate it from other clinical trial tools that might serve different purposes like detailed record retrieval.

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