clinicaltrialsgov-mcp-server

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

Annotations declare readOnly/idempotent safety; description adds critical behavioral context: specific data categories returned, the hasResults availability constraint, and payload characteristics implied by the summary parameter description in schema. 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?

Three sentences, each serving distinct purpose: (1) capability/data types, (2) availability constraint, (3) workflow prerequisite. No filler; front-loaded with action verb.

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 output schema exists and annotations cover safety profile, description provides sufficient domain context: data categories, completion status requirement, and sibling dependency. Adequate for a 3-parameter clinical data 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 coverage is 100% with detailed descriptions for all 3 parameters (nctIds pattern/examples, sections enum, summary payload reduction). Description does not redundantly describe parameters, which is appropriate given schema completeness. Baseline 3.

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?

States specific action ('Fetch trial results data') and resource ('completed studies'), distinguishing from siblings like get_study_record by specifying result-specific content: 'outcome measures with statistics, adverse events, participant flow, and baseline characteristics.'

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?

Provides explicit when-to-use constraint ('Only available for studies where hasResults is true') and prerequisite workflow ('Use search_studies first to find studies with results'), clearly directing the agent to the sibling search tool before invocation.

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