MCP Knowledge Base Server

Instructions

Implementation Reference

• src/index.ts:313-369 (handler)

  Executes the get_by_category tool: extracts category from args, validates it, filters the knowledgeBase array case-insensitively, handles no-results case with available categories list, formats and returns JSON response with entries (id, content, metadata), caches successful results.

  if (name === "get_by_category") {
    const category = args?.category as string;
  
    if (!category) {
      throw new Error("Category parameter is required");
    }
  
    const results = knowledgeBase.filter(
      (item) => item.category.toLowerCase() === category.toLowerCase()
    );
  
    if (results.length === 0) {
      const responseText = JSON.stringify({
        category,
        message: "No entries found for this category",
        availableCategories: [
          ...new Set(knowledgeBase.map((item) => item.category)),
        ],
      });
  
      // Don't cache errors
      return {
        content: [
          {
            type: "text",
            text: responseText,
          },
        ],
      };
    }
  
    const responseText = JSON.stringify(
      {
        category,
        count: results.length,
        entries: results.map((r) => ({
          id: r.id,
          content: r.content,
          metadata: r.metadata,
        })),
      },
      null,
      2
    );
  
    // Cache the response
    setCache(cacheKey, responseText);
  
    return {
      content: [
        {
          type: "text",
          text: responseText,
        },
      ],
    };
  }

• src/index.ts:166-179 (registration)

  Registers the get_by_category tool in the tools list provided to MCP clients, including name, description, and input schema requiring a 'category' string.

  {
      name: "get_by_category",
      description: "Get all knowledge base entries for a specific category",
      inputSchema: {
        type: "object",
        properties: {
          category: {
            type: "string",
            description: "Category to filter by (e.g., 'ai', 'technology', 'product')",
          },
        },
        required: ["category"],
      },
    },

• src/index.ts:169-178 (schema)

  Input schema for get_by_category tool: object with required 'category' string property.

  inputSchema: {
    type: "object",
    properties: {
      category: {
        type: "string",
        description: "Category to filter by (e.g., 'ai', 'technology', 'product')",
      },
    },
    required: ["category"],
  },