Brex MCP Server

Instructions

Implementation Reference

• src/tools/getSpendLimitById.ts:29-47 (handler)

  Core handler logic for the 'get_spend_limit' tool: validates parameters, fetches the spend limit using BrexClient, formats response as JSON, and handles errors.

  registerToolHandler("get_spend_limit", async (request: ToolCallRequest) => {
    try {
      const params = validateParams(request.params.arguments);
      const client = getBrexClient();
      const spendLimit = await client.getSpendLimit(params.id);
      
      return { 
        content: [{ 
          type: "text", 
          text: JSON.stringify({ 
            spend_limit: spendLimit 
          }, null, 2) 
        }] 
      };
    } catch (error) {
      logError(`Error in get_spend_limit: ${error instanceof Error ? error.message : String(error)}`);
      throw error;
    }
  });

• src/tools/index.ts:123-133 (schema)

  MCP tool schema definition for 'get_spend_limit', specifying input as object with required 'id' string field.

  {
    name: "get_spend_limit",
    description: "Get a spend limit by ID (read-only). Example: {\"id\":\"sl_123\"}",
    inputSchema: {
      type: "object",
      properties: {
        id: { type: "string" }
      },
      required: ["id"]
    }
  },

• src/tools/getSpendLimitById.ts:28-48 (registration)

  Local registration of the 'get_spend_limit' tool handler using registerToolHandler.

  export function registerGetSpendLimitById(_server: Server): void {
    registerToolHandler("get_spend_limit", async (request: ToolCallRequest) => {
      try {
        const params = validateParams(request.params.arguments);
        const client = getBrexClient();
        const spendLimit = await client.getSpendLimit(params.id);
        
        return { 
          content: [{ 
            type: "text", 
            text: JSON.stringify({ 
              spend_limit: spendLimit 
            }, null, 2) 
          }] 
        };
      } catch (error) {
        logError(`Error in get_spend_limit: ${error instanceof Error ? error.message : String(error)}`);
        throw error;
      }
    });
  }

• src/tools/index.ts:66-66 (registration)

  Top-level invocation of registerGetSpendLimitById during tools registration.

  registerGetSpendLimitById(server);

• src/tools/getSpendLimitById.ts:14-26 (schema)

  TypeScript interface and validation function for tool input parameters.

  interface GetSpendLimitParams { 
    id: string; 
  }
  
  function validateParams(input: unknown): GetSpendLimitParams {
    const raw = (input || {}) as Record<string, unknown>;
    if (!raw.id) {
      throw new Error("Missing required parameter: id");
    }
    return { 
      id: String(raw.id) 
    };
  }