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

Annotations already establish the safety profile (readOnlyHint, idempotentHint, non-destructive). The description adds useful behavioral context beyond that: the set of returned fields, pagination support, and the data source (NIH US Gov, public domain). It stops short of disclosing potential rate limits or error behavior, but the annotation coverage lowers the burden.

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 with no fluff. The first sentence front-loads the core purpose and search fields, the second covers return fields, and the third handles pagination and data provenance. Every sentence earns its place.

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 output schema, annotations, and rich parameter schema, the description covers the essential operational aspects: what is searched, optional filters, returned data, pagination, and data source. There is no missing information an agent would need to invoke this tool correctly.

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% and every parameter has a meaningful description, including enum explanations for phase and status. The description reinforces these parameters by listing search dimensions (condition, drug/intervention, sponsor, keyword) and pagination, but adds little new semantic information beyond the schema.

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 uses a specific verb ('Search') with a clear resource ('clinical trials registered on ClinicalTrials.gov') and enumerates search dimensions (condition, drug/intervention, sponsor, keyword). It also lists return fields, which makes the tool's scope concrete and distinguishable from siblings like detail, recruiting, and stats.

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 context on how to use the tool: search criteria, optional filters by status and phase, and pagination via page_token. However, it does not explicitly state when to prefer this tool over sibling tools such as clinicaltrials.trials.detail or clinicaltrials.trials.recruiting, nor does it mention exclusions.

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