clinicaltrialsgov-mcp-server

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

While annotations declare readOnlyHint and openWorldHint, the description adds valuable behavioral context by explicitly naming ClinicalTrials.gov as the external dependency, noting that it 'builds an optimized query' (explaining the processing logic), and clarifying that results are 'for the caller to evaluate' (setting expectations that the tool performs matching but not medical eligibility determination). No contradictions with annotations.

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 consists of two highly efficient sentences. The first front-loads the core action and resource, while the second explains the mechanism (optimized query building) and output scope (eligibility and location fields). Every phrase serves a purpose, including 'for the caller to evaluate,' which critically delineates the tool's responsibility boundary.

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 (medical domain, external API dependency, 7 parameters, nested objects) and the presence of a complete input schema and output schema, the description provides sufficient context by identifying the external data source, the optimization behavior, and the evaluation limitation. It appropriately avoids duplicating parameter-level details already covered by the 100% schema coverage.

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?

With 100% schema description coverage, the schema fully documents all 7 parameters including nested location fields and boolean flags. The description references the parameters conceptually as a 'patient profile (age, sex, conditions, location),' which provides semantic grouping but does not add syntax or format details beyond what the schema already provides. Baseline score of 3 is appropriate given the schema carries the full documentation burden.

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 explicitly states the tool matches patient profiles to eligible clinical trials, specifies the target resource (ClinicalTrials.gov), and lists the key input components (age, sex, conditions, location). It clearly distinguishes itself from sibling tools by emphasizing 'eligible recruiting' trials and patient-specific matching rather than general study retrieval or metadata lookups.

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 clear contextual signals for when to use the tool (when you have a patient profile and need to find eligible trials) by specifying 'patient profile' and 'eligible recruiting.' However, it does not explicitly name alternative tools like 'clinicaltrials_search_studies' for broader queries or state when NOT to use this tool.

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