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

Annotations already declare readOnlyHint=true, openWorldHint=true, and destructiveHint=false. The description goes beyond these by specifying the data source (ClinicalTrials.gov), output format (JSON), cost and payment mechanism ($0.05 USDC via x402), and the time scope ('recent'). It also notes 'One call', implying a bundled, non-paginated response. These are useful behavioral details beyond the 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 is compact and well-structured, with the tool name and core purpose front-loaded. Each segment adds distinct value: scope, return fields, source, use case, output format, and pricing. No filler or redundant phrasing.

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?

Even though there is no output schema, the description compensates by listing the exact response fields (NCT id, title, status, phase, sponsor, last-update date), the source, and the pricing. For a read-only search tool with two optional parameters, this is sufficient information for an agent to invoke it correctly and understand the result.

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%, with both condition and intervention already described. The description's phrase 'condition and/or intervention' clarifies that the parameters can be combined, but it does not add meaningful syntax or format details beyond what the schema already provides. Baseline 3 is appropriate.

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 states a specific verb and resource: 'Clinical trials search' for ClinicalTrials.gov trials. It enumerates the returned fields (NCT id, title, status, phase, sponsor, last-update date), making the output clear and distinguishing this tool from siblings like fda_drug_label or fda_recalls simply by domain and source.

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 broad context ('For pharma, research, diligence') and implies usage for finding recent trials by condition and/or intervention, but it does not explicitly state when to use this tool instead of alternatives such as fda_drug_label or fda_recalls, nor does it mention any exclusions or fallback cases.

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