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MoralisWeb3

Moralis MCP Server

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by MoralisWeb3

evm_getdefipositionsbyprotocol

Fetch detailed DeFi positions for a specific wallet and protocol to analyze holdings and exposure across multiple blockchain networks.

Instructions

Fetch detailed DeFi positions for a given wallet and protocol.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
chainNoThe chain to queryeth
addressYesWallet address
protocolYesThe protocol to queryuniswap-v3

Implementation Reference

  • The core handler function that executes the tool by making an authenticated HTTP request to the Moralis API endpoint corresponding to the tool's OpenAPI operation. Used for all prefixed tools including evm_getdefipositionsbyprotocol.
    export async function executeApiTool(
      toolName: string,
      definition: McpToolDefinition,
      toolArgs: JsonObject,
      allSecuritySchemes: Record<string, any>,
      token?: string,
    ): Promise<CallToolResult> {
      try {
        // Validate arguments against the input schema
        let validatedArgs: JsonObject;
        try {
          const zodSchema = getZodSchemaFromJsonSchema(
            definition.inputSchema,
            toolName,
          );
          const argsToParse =
            typeof toolArgs === 'object' && toolArgs !== null ? toolArgs : {};
          validatedArgs = zodSchema.parse(argsToParse);
        } catch (error: unknown) {
          if (error instanceof ZodError) {
            const validationErrorMessage = `Invalid arguments for tool '${toolName}': ${error.errors.map((e) => `${e.path.join('.')} (${e.code}): ${e.message}`).join(', ')}`;
            return { content: [{ type: 'text', text: validationErrorMessage }] };
          } else {
            const errorMessage =
              error instanceof Error ? error.message : String(error);
            return {
              content: [
                {
                  type: 'text',
                  text: `Internal error during validation setup: ${errorMessage}`,
                },
              ],
            };
          }
        }
    
        // Prepare URL, query parameters, headers, and request body
        let urlPath = definition.pathTemplate;
        const queryParams: Record<string, any> = {};
        const headers: Record<string, string> = {
          Accept: 'application/json',
          'X-Moralis-Platform': 'MCP',
        };
        let requestBodyData: any = undefined;
    
        // Apply parameters to the URL path, query, or headers
        definition.executionParameters.forEach((param) => {
          const value = validatedArgs[param.name];
          if (typeof value !== 'undefined' && value !== null) {
            if (param.in === 'path') {
              urlPath = urlPath.replace(
                `{${param.name}}`,
                encodeURIComponent(String(value)),
              );
            } else if (param.in === 'query') {
              queryParams[param.name] = value;
            } else if (param.in === 'header') {
              headers[param.name.toLowerCase()] = String(value);
            }
          }
        });
    
        // Ensure all path parameters are resolved
        if (urlPath.includes('{')) {
          throw new Error(`Failed to resolve path parameters: ${urlPath}`);
        }
    
        // Construct the full URL
        const requestUrl = `${definition.baseUrl}${urlPath}`;
    
        // Handle request body if needed
        if (
          definition.requestBodyContentType &&
          typeof validatedArgs['requestBody'] !== 'undefined'
        ) {
          requestBodyData = validatedArgs['requestBody'];
          headers['content-type'] = definition.requestBodyContentType;
        }
    
        // Apply security requirements if available
        // Security requirements use OR between array items and AND within each object
        const appliedSecurity = definition.securityRequirements?.find((req) => {
          // Try each security requirement (combined with OR)
          return Object.entries(req).every(([schemeName, scopesArray]) => {
            const scheme = allSecuritySchemes[schemeName];
            if (!scheme) return false;
    
            // API Key security (header, query, cookie)
            if (scheme.type === 'apiKey') {
              return !!token || !!Config.MORALIS_API_KEY;
            }
    
            return false;
          });
        });
    
        // If we found matching security scheme(s), apply them
        if (appliedSecurity) {
          // Apply each security scheme from this requirement (combined with AND)
          for (const [schemeName, scopesArray] of Object.entries(appliedSecurity)) {
            const scheme = allSecuritySchemes[schemeName];
    
            // API Key security
            if (scheme?.type === 'apiKey') {
              const apiKey = token || Config.MORALIS_API_KEY;
              if (apiKey) {
                if (scheme.in === 'header') {
                  headers[scheme.name.toLowerCase()] = apiKey;
                  console.error(
                    `Applied API key '${schemeName}' in header '${scheme.name}'`,
                  );
                }
              }
            }
          }
        }
        // Log warning if security is required but not available
        else if (definition.securityRequirements?.length > 0) {
          // First generate a more readable representation of the security requirements
          const securityRequirementsString = definition.securityRequirements
            .map((req) => {
              const parts = Object.entries(req)
                .map(([name, scopesArray]) => {
                  const scopes = scopesArray as string[];
                  if (scopes.length === 0) return name;
                  return `${name} (scopes: ${scopes.join(', ')})`;
                })
                .join(' AND ');
              return `[${parts}]`;
            })
            .join(' OR ');
    
          console.warn(
            `Tool '${toolName}' requires security: ${securityRequirementsString}, but no suitable credentials found.`,
          );
        }
    
        // Prepare the axios request configuration
        const config: AxiosRequestConfig = {
          method: definition.method.toUpperCase(),
          url: requestUrl,
          params: queryParams,
          headers: headers,
          ...(requestBodyData !== undefined && { data: requestBodyData }),
        };
    
        // Log request info to stderr (doesn't affect MCP output)
        console.error(
          `Executing tool "${toolName}": ${config.method} ${config.url}`,
        );
    
        // Execute the request
        const response = await axios(config);
    
        // Process and format the response
        let responseText = '';
        const contentType = response.headers['content-type']?.toLowerCase() || '';
    
        // Handle JSON responses
        if (
          contentType.includes('application/json') &&
          typeof response.data === 'object' &&
          response.data !== null
        ) {
          try {
            responseText = JSON.stringify(response.data, null, 2);
          } catch (e) {
            responseText = '[Stringify Error]';
          }
        }
        // Handle string responses
        else if (typeof response.data === 'string') {
          responseText = response.data;
        }
        // Handle other response types
        else if (response.data !== undefined && response.data !== null) {
          responseText = String(response.data);
        }
        // Handle empty responses
        else {
          responseText = `(Status: ${response.status} - No body content)`;
        }
    
        // Return formatted response
        return {
          content: [
            {
              type: 'text',
              text: `API Response (Status: ${response.status}):\n${responseText}`,
            },
          ],
        };
      } catch (error: unknown) {
        // Handle errors during execution
        let errorMessage: string;
    
        // Format Axios errors specially
        if (axios.isAxiosError(error)) {
          errorMessage = formatApiError(error);
        }
        // Handle standard errors
        else if (error instanceof Error) {
          errorMessage = error.message;
        }
        // Handle unexpected error types
        else {
          errorMessage = `Unexpected error: ${String(error)}`;
        }
    
        // Log error to stderr
        console.error(
          `Error during execution of tool '${toolName}':`,
          errorMessage,
        );
    
        // Return error message to client
        return { content: [{ type: 'text', text: errorMessage }] };
      }
    }
  • src/server.ts:26-44 (registration)
    Function that fetches the OpenAPI spec for EVM (or other), extracts tool definitions with 'evm_' prefix, and builds the toolDefinitionMap used for registration of tools like evm_getdefipositionsbyprotocol.
    async function mapToolDefinitions(config: SchemaConfig) {
      const spec = (await getSpec(config.specUrl)) as OpenAPIV3DocumentX;
      const api = (await SwaggerParser.dereference(spec)) as OpenAPIV3DocumentX;
    
      const tools = extractToolsFromApi(api, config.prefix);
      const blacklist = Array.isArray(api['x-mcp-blacklist'])
        ? api['x-mcp-blacklist'].map((e) => `${config.prefix}${e.toLowerCase()}`)
        : [];
    
      const toolDefinitionMap: Record<string, McpToolDefinition> = {};
      for (const tool of tools) {
        if (blacklist.includes(tool.name)) continue;
        toolDefinitionMap[tool.name] = {
          ...tool,
          baseUrl: config.baseUrl,
        };
      }
      return toolDefinitionMap;
    }
  • src/server.ts:96-120 (registration)
    MCP server request handler for calling tools. Looks up the tool definition by name (e.g., 'evm_getdefipositionsbyprotocol') and invokes the generic executeApiTool handler.
    server.setRequestHandler(
      CallToolRequestSchema,
      async (request: CallToolRequest, c): Promise<CallToolResult> => {
        const { name: toolName, arguments: toolArgs } = request.params;
        const toolDefinition = toolDefinitionMap[toolName];
        if (!toolDefinition) {
          console.error(`Error: Unknown tool requested: ${toolName}`);
          return {
            content: [
              {
                type: 'text',
                text: `Error: Unknown tool requested: ${toolName}`,
              },
            ],
          };
        }
        return executeApiTool(
          toolName,
          toolDefinition,
          toolArgs ?? {},
          securitySchemes,
          c.authInfo?.token,
        );
      },
    );
  • Generates the inputSchema for each tool from the OpenAPI operation's parameters and requestBody. Used during tool extraction for schema definition.
    export function generateInputSchemaAndDetails(
      operation: OpenAPIV3.OperationObject,
    ): {
      inputSchema: JSONSchema7 | boolean;
      parameters: OpenAPIV3.ParameterObject[];
      requestBodyContentType?: string;
    } {
      const properties: { [key: string]: JSONSchema7 | boolean } = {};
      const required: string[] = [];
    
      // Process parameters
      const allParameters: OpenAPIV3.ParameterObject[] = Array.isArray(
        operation.parameters,
      )
        ? operation.parameters.map((p) => p as OpenAPIV3.ParameterObject)
        : [];
    
      allParameters.forEach((param) => {
        if (!param.name || !param.schema) return;
    
        const paramSchema = mapOpenApiSchemaToJsonSchema(
          param.schema as OpenAPIV3.SchemaObject,
        );
        if (typeof paramSchema === 'object') {
          paramSchema.description = param.description || paramSchema.description;
        }
    
        properties[param.name] = paramSchema;
        if (param.required) required.push(param.name);
      });
    
      // Process request body (if present)
      let requestBodyContentType: string | undefined = undefined;
    
      if (operation.requestBody) {
        const opRequestBody = operation.requestBody as OpenAPIV3.RequestBodyObject;
        const jsonContent = opRequestBody.content?.['application/json'];
        const firstContent = opRequestBody.content
          ? Object.entries(opRequestBody.content)[0]
          : undefined;
    
        if (jsonContent?.schema) {
          requestBodyContentType = 'application/json';
          const bodySchema = mapOpenApiSchemaToJsonSchema(
            jsonContent.schema as OpenAPIV3.SchemaObject,
          );
    
          if (typeof bodySchema === 'object') {
            bodySchema.description =
              opRequestBody.description ||
              bodySchema.description ||
              'The JSON request body.';
          }
    
          properties['requestBody'] = bodySchema;
          if (opRequestBody.required) required.push('requestBody');
        } else if (firstContent) {
          const [contentType] = firstContent;
          requestBodyContentType = contentType;
    
          properties['requestBody'] = {
            type: 'string',
            description:
              opRequestBody.description ||
              `Request body (content type: ${contentType})`,
          };
    
          if (opRequestBody.required) required.push('requestBody');
        }
      }
    
      // Combine everything into a JSON Schema
      const inputSchema: JSONSchema7 = {
        type: 'object',
        properties,
        ...(required.length > 0 && { required }),
      };
    
      return { inputSchema, parameters: allParameters, requestBodyContentType };
    }
  • Main helper that extracts all MCP tools from OpenAPI spec, assigning names like 'evm_getdefipositionsbyprotocol' based on operationId 'getdefipositionsbyprotocol', generating schemas and defs.
    export function extractToolsFromApi(
      api: OpenAPIV3DocumentX,
      prefix?: string
    ): McpToolDefinition[] {
      const tools: McpToolDefinition[] = [];
      const usedNames = new Set<string>();
      const globalSecurity = api.security || [];
    
      if (!api.paths) return tools;
    
      for (const [path, pathItem] of Object.entries(api.paths)) {
        if (!pathItem) continue;
    
        for (const method of Object.values(OpenAPIV3.HttpMethods)) {
          const operation = pathItem[method];
          if (!operation) continue;
    
          // Generate a unique name for the tool
          let baseName = operation.operationId || generateOperationId(method, path);
          if (!baseName) continue;
    
          // Sanitize the name to be MCP-compatible (only a-z, 0-9, _, -)
          baseName = baseName
            .replace(/\./g, '_')
            .replace(/[^a-z0-9_-]/gi, '_')
            .toLowerCase();
    
          let finalToolName = baseName;
          let counter = 1;
          while (usedNames.has(finalToolName)) {
            finalToolName = `${baseName}_${counter++}`;
          }
          usedNames.add(finalToolName);
    
          // Get or create a description
          const description =
            operation.description ||
            operation.summary ||
            `Executes ${method.toUpperCase()} ${path}`;
    
          const prompt = operation['x-mcp-prompt'];
    
          // Generate input schema and extract parameters
          const { inputSchema, parameters, requestBodyContentType } =
            generateInputSchemaAndDetails(operation);
    
          // Extract parameter details for execution
          const executionParameters = parameters.map((p) => ({
            name: p.name,
            in: p.in,
          }));
    
          // Determine security requirements
          const securityRequirements =
            operation.security === null
              ? globalSecurity
              : operation.security || globalSecurity;
    
          // Create the tool definition
          tools.push({
            name: prefix + finalToolName,
            description,
            inputSchema,
            method,
            pathTemplate: path,
            parameters,
            executionParameters,
            requestBodyContentType,
            securityRequirements,
            operationId: baseName,
            prompt,
          });
        }
      }
    
      return tools;
    }
Behavior2/5

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It states the tool fetches data, implying a read-only operation, but does not specify whether it requires authentication, has rate limits, returns paginated results, or details the format of 'detailed DeFi positions'. This leaves significant gaps in understanding the tool's behavior and constraints.

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, efficient sentence that directly states the tool's purpose without any redundant information. It is front-loaded and appropriately sized, making it easy to understand quickly with zero waste.

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

Completeness2/5

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

Given the complexity of DeFi positions and the lack of annotations and output schema, the description is insufficient. It does not explain what 'detailed DeFi positions' include, how data is structured, or any behavioral traits like error handling or data freshness. This leaves the agent with incomplete context for effective tool invocation.

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 input schema has 100% description coverage, with clear parameter descriptions and enums, so the baseline score is 3. The description adds minimal value by mentioning 'wallet and protocol', which aligns with the schema but does not provide additional semantic context or usage examples beyond what is already documented in the structured fields.

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 the action ('Fetch detailed DeFi positions') and specifies the target resources ('for a given wallet and protocol'), making the purpose unambiguous. However, it does not explicitly differentiate from its sibling 'evm_getdefipositionssummary', which might provide a summary instead of detailed positions, leaving room for improvement in sibling distinction.

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?

The description provides no guidance on when to use this tool versus alternatives, such as 'evm_getdefipositionssummary' or other DeFi-related tools in the sibling list. It lacks explicit context, prerequisites, or exclusions, offering minimal usage direction beyond the basic parameters.

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

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