Fetch one canonical trial by id, with every registry's provenance + cross-registry IDs.
Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.
{
"id": 1,
"jsonrpc": "2.0",
"method": "tools/call",
"params": {
"arguments": {
"id": "<id>"
},
"name": "trials_get"
}
}| Name | Required | Description | Default |
|---|---|---|---|
| id | Yes |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The annotations already declare readOnlyHint, idempotentHint and openWorldHint=false, so the safety profile is covered. The description adds that the result is a canonical record carrying provenance from every registry plus cross-registry identifiers, which is genuinely useful payload context in the absence of an output schema, but it says nothing about error behavior for a missing id or how conflicts between registries are resolved.
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?
A single dense sentence with no filler; the resource and its scoping ('one canonical trial by id') come first and the return payload follows. Every phrase carries information.
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?
With no output schema, the description must carry the return-value burden, and it does partially by naming the provenance and cross-registry ID content. It still leaves the id domain and failure behavior unspecified, which is a notable gap for a lookup tool an agent will call speculatively.
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?
There is one parameter at 0% schema description coverage; the schema only constrains it to a positive integer. The description clarifies that the id identifies a canonical trial, but it does not resolve the key ambiguity of whether this is an internal record id or a registry identifier such as an NCT number, which matters precisely because the tool returns cross-registry IDs.
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 a specific verb and resource: 'Fetch one canonical trial by id'. The word 'one' combined with 'canonical' implicitly separates it from the sibling trials_search (which returns sets), though the sibling is never named, so the differentiation is suggestive rather than explicit.
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?
Usage is only implied: an agent infers you call this when you already hold an id and want the single merged record. There is no explicit when-to-use vs. when-to-search guidance, no note that trials_search should be used first to discover ids, and no stated behavior when the id is unknown.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.