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BACH-AI-Tools

Clinical Trials MCP Server

search_by_primary_outcome

Find clinical trials by specifying primary outcome measures or endpoints, with optional filters for condition and study phase.

Instructions

Search clinical trials by primary outcome measures or endpoints

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
outcomeYesPrimary outcome or endpoint to search for
conditionNoOptional condition filter
phaseNoStudy phase filter
pageSizeNoNumber of results to return (default 10, max 100)

Implementation Reference

  • Handler for search_by_primary_outcome tool.
    private async handleSearchByPrimaryOutcome(args: any) {
      if (!args?.outcome) {
        throw new McpError(
          ErrorCode.InvalidParams,
          "Outcome parameter is required"
        );
      }
    
      const params: any = {
        format: "json",
        pageSize: args?.pageSize || 10,
        "query.outc": args.outcome,
      };
    
      if (args?.condition) {
        params["query.cond"] = args.condition;
      }
    
      if (args?.phase) {
        params["filter.phase"] = args.phase;
      }
    
      try {
        const response: AxiosResponse<StudySearchResponse> =
          await this.axiosInstance.get("/studies", { params });
    
        const studies = response.data.studies || [];
        const results = studies.map((study) => this.formatStudySummary(study));
    
        return {
          content: [
            {
              type: "text",
              text: JSON.stringify(
                {
                  searchCriteria: {
                    primaryOutcome: args.outcome,
                    condition: args?.condition,
                    phase: args?.phase,
                  },
                  totalCount: response.data.totalCount || 0,
                  resultsShown: results.length,
                  studies: results,
                },
                null,
                2
              ),
            },
          ],
        };
      } catch (error) {
        if (axios.isAxiosError(error)) {
          return {
            content: [
              {
                type: "text",
                text: `Clinical Trials API error: ${
                  error.response?.data?.message || error.message
                }`,
              },
            ],
            isError: true,
          };
        }
        throw error;
      }
    }
  • Schema definition for search_by_primary_outcome tool.
      name: "search_by_primary_outcome",
      description:
        "Search clinical trials by primary outcome measures or endpoints",
      inputSchema: {
        type: "object",
        properties: {
          outcome: {
            type: "string",
            description: "Primary outcome or endpoint to search for",
            minLength: 3,
          },
          condition: {
            type: "string",
            description: "Optional condition filter",
          },
          phase: {
            type: "string",
            description: "Study phase filter",
            enum: ["PHASE1", "PHASE2", "PHASE3", "PHASE4", "NA"],
          },
          pageSize: {
            type: "number",
            description:
              "Number of results to return (default 10, max 100)",
            minimum: 1,
            maximum: 100,
          },
        },
        required: ["outcome"],
      },
    },
  • src/index.ts:758-761 (registration)
    Registration/routing for search_by_primary_outcome tool.
    case "search_by_primary_outcome":
      return await this.handleSearchByPrimaryOutcome(
        request.params.arguments
      );

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observedv1.0.1

TDQS

B3.1/5.0
Behavior2/5

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

With no annotations, the description must fully disclose behavioral traits, but it only states the basic function. It does not mention return format, pagination defaults, or scope limitations, leaving the agent to infer behavior.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, focused sentence with no filler. The action and target are front-loaded, making it easy to parse quickly.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the complete schema and a straightforward search tool, the description is adequate but not rich. It lacks usage differentiation and behavioral context, which matters more due to the many sibling search tools and absence of annotations.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema covers all 4 parameters with descriptions, so the baseline is 3. The description adds no additional meaning beyond what the schema already provides for the outcome parameter.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states a specific action (search clinical trials) and the target attribute (primary outcome measures or endpoints). It distinguishes the tool by its focus on primary outcomes, though it does not explicitly compare to sibling tools like search_by_condition or search_studies.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is no guidance on when to use this tool versus alternative search tools. It does not mention preferred contexts, exclusions, or when another search-by-filter would be more appropriate.

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