Brex MCP Server

Instructions

Implementation Reference

• src/tools/getBudgetById.ts:27-43 (handler)

  Main execution handler for the 'get_budget' tool: validates input, fetches budget via BrexClient.getBudget, returns JSON response.

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

• src/tools/getBudgetById.ts:14-24 (schema)

  Type definition and validation logic for get_budget input parameters.

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

• src/tools/index.ts:98-108 (schema)

  Official MCP input schema for the 'get_budget' tool in the listTools handler.

  {
    name: "get_budget",
    description: "Get a budget by ID (read-only). Returns the complete budget object. Example: {\"budget_id\":\"budget_123\"}",
    inputSchema: {
      type: "object",
      properties: {
        budget_id: { type: "string", description: "The ID of the budget to retrieve" }
      },
      required: ["budget_id"]
    }
  },

• src/tools/index.ts:64-64 (registration)

  Tool registration call within registerTools function.

  registerGetBudgetById(server);

• src/index.ts:48-48 (registration)

  Top-level server registration that includes get_budget tool.

  registerTools(server);