Memory Bank MCP

Instructions

Implementation Reference

• index.ts:575-687 (handler)

  The main execution logic of the init-memory-bank tool. Handles directory creation, template generation and file writing for the memory bank system.

    async ({ rootPath, force = false }) => {
      const normalizedPath = normalizePath(rootPath);
      const memoryBankPath = path.join(normalizedPath, "memory-bank");
  
      try {
        // Check if directory exists
        if (existsSync(memoryBankPath) && !force) {
          const files = await fs.readdir(memoryBankPath);
          if (files.length > 0) {
            return {
              content: [
                {
                  type: "text",
                  text: `[MEMORY BANK: EXISTS]
  
  memory-bank directory already exists and contains files. To re-initialize, use force: true parameter.
  
  Existing files:
  ${files.map((f) => `- ${f}`).join("\n")}
  
  Suggestions:
  - Use get-memory-bank-info to read existing content
  - If you really need to re-initialize, set force: true`,
                },
              ],
            };
          }
        }
  
        // Create directory
        await fs.mkdir(memoryBankPath, { recursive: true });
  
        // Check if projectBrief.md exists
        let projectBriefContent = "";
        const projectBriefPath = path.join(normalizedPath, "projectBrief.md");
        if (existsSync(projectBriefPath)) {
          try {
            projectBriefContent = await fs.readFile(projectBriefPath, "utf-8");
          } catch (err) {
            console.error("Failed to read projectBrief.md:", err);
          }
        }
  
        // Get templates
        const templates = getMemoryBankTemplates();
  
        // If projectBrief exists, update productContext.md template
        if (projectBriefContent) {
          templates["productContext.md"] = templates["productContext.md"].replace(
            "## Project Goal\n\n*   ",
            `## Project Goal\n\n*Based on projectBrief.md content:*\n\n${projectBriefContent}\n\n*Extract and define project goals from the above content:*\n\n*   `
          );
        }
  
        // Create all files
        const createdFiles: string[] = [];
        for (const [filename, content] of Object.entries(templates)) {
          const filePath = path.join(memoryBankPath, filename);
          await fs.writeFile(filePath, content, "utf-8");
          createdFiles.push(filename);
        }
  
        return {
          content: [
            {
              type: "text",
              text: `[MEMORY BANK: INITIALIZED]
  
  Memory Bank has been successfully initialized!
  
  Created files:
  ${createdFiles.map((f) => `- ${f}`).join("\n")}
  
  ${
    projectBriefContent
      ? "✓ Read projectBrief.md and integrated into productContext.md\n\n"
      : ""
  }
  
  [ATTENTION] Next steps to execute:
  1. Read and update each memory-bank/*.md file
  2. Fill in relevant content following the guidance in each file
  3. Do not use get-memory-bank-info before completing initial edits
  4. After completing edits, you can start using Memory Bank
  
  Important file descriptions:
  - productContext.md: Define project goals, features, and architecture
  - activeContext.md: Track current work status and focus
  - progress.md: Manage task progress
  - decisionLog.md: Record important decisions
  - systemPatterns.md: Document code patterns and standards
  
  Maintenance Tips:
  - Keep each file under 300 lines for optimal performance
  - Archive old content daily/weekly to memory-bank/archive/
  - Use update-memory-bank tool for detailed maintenance guidance
  - Check file sizes after each work session`,
            },
          ],
        };
      } catch (error) {
        return {
          content: [
            {
              type: "text",
              text: `Error initializing Memory Bank: ${
                error instanceof Error ? error.message : String(error)
              }`,
            },
          ],
        };
      }
    }

• index.ts:564-574 (schema)

  Input schema validation using Zod for the tool parameters: rootPath (required string) and force (optional boolean).

  {
    rootPath: z.string().describe(
      `Project root directory path
      Windows example: "C:/Users/name/project" 
      macOS/Linux example: "/home/name/project"`
    ),
    force: z
      .boolean()
      .optional()
      .describe("Force re-initialization (will overwrite existing files)"),
  },

• index.ts:556-688 (registration)

  The server.tool call that registers the 'init-memory-bank' tool with its name, description, input schema, and handler function.

  server.tool(
    "init-memory-bank",
    `Initialize memory-bank directory and core files.
    This tool will:
    - Create memory-bank directory
    - Generate initial templates for 5 core files
    - Read and integrate projectBrief.md if it exists
    - Provide next steps guidance`,
    {
      rootPath: z.string().describe(
        `Project root directory path
        Windows example: "C:/Users/name/project" 
        macOS/Linux example: "/home/name/project"`
      ),
      force: z
        .boolean()
        .optional()
        .describe("Force re-initialization (will overwrite existing files)"),
    },
    async ({ rootPath, force = false }) => {
      const normalizedPath = normalizePath(rootPath);
      const memoryBankPath = path.join(normalizedPath, "memory-bank");
  
      try {
        // Check if directory exists
        if (existsSync(memoryBankPath) && !force) {
          const files = await fs.readdir(memoryBankPath);
          if (files.length > 0) {
            return {
              content: [
                {
                  type: "text",
                  text: `[MEMORY BANK: EXISTS]
  
  memory-bank directory already exists and contains files. To re-initialize, use force: true parameter.
  
  Existing files:
  ${files.map((f) => `- ${f}`).join("\n")}
  
  Suggestions:
  - Use get-memory-bank-info to read existing content
  - If you really need to re-initialize, set force: true`,
                },
              ],
            };
          }
        }
  
        // Create directory
        await fs.mkdir(memoryBankPath, { recursive: true });
  
        // Check if projectBrief.md exists
        let projectBriefContent = "";
        const projectBriefPath = path.join(normalizedPath, "projectBrief.md");
        if (existsSync(projectBriefPath)) {
          try {
            projectBriefContent = await fs.readFile(projectBriefPath, "utf-8");
          } catch (err) {
            console.error("Failed to read projectBrief.md:", err);
          }
        }
  
        // Get templates
        const templates = getMemoryBankTemplates();
  
        // If projectBrief exists, update productContext.md template
        if (projectBriefContent) {
          templates["productContext.md"] = templates["productContext.md"].replace(
            "## Project Goal\n\n*   ",
            `## Project Goal\n\n*Based on projectBrief.md content:*\n\n${projectBriefContent}\n\n*Extract and define project goals from the above content:*\n\n*   `
          );
        }
  
        // Create all files
        const createdFiles: string[] = [];
        for (const [filename, content] of Object.entries(templates)) {
          const filePath = path.join(memoryBankPath, filename);
          await fs.writeFile(filePath, content, "utf-8");
          createdFiles.push(filename);
        }
  
        return {
          content: [
            {
              type: "text",
              text: `[MEMORY BANK: INITIALIZED]
  
  Memory Bank has been successfully initialized!
  
  Created files:
  ${createdFiles.map((f) => `- ${f}`).join("\n")}
  
  ${
    projectBriefContent
      ? "✓ Read projectBrief.md and integrated into productContext.md\n\n"
      : ""
  }
  
  [ATTENTION] Next steps to execute:
  1. Read and update each memory-bank/*.md file
  2. Fill in relevant content following the guidance in each file
  3. Do not use get-memory-bank-info before completing initial edits
  4. After completing edits, you can start using Memory Bank
  
  Important file descriptions:
  - productContext.md: Define project goals, features, and architecture
  - activeContext.md: Track current work status and focus
  - progress.md: Manage task progress
  - decisionLog.md: Record important decisions
  - systemPatterns.md: Document code patterns and standards
  
  Maintenance Tips:
  - Keep each file under 300 lines for optimal performance
  - Archive old content daily/weekly to memory-bank/archive/
  - Use update-memory-bank tool for detailed maintenance guidance
  - Check file sizes after each work session`,
            },
          ],
        };
      } catch (error) {
        return {
          content: [
            {
              type: "text",
              text: `Error initializing Memory Bank: ${
                error instanceof Error ? error.message : String(error)
              }`,
            },
          ],
        };
      }
    }
  );

• index.ts:51-152 (helper)

  Supporting function that generates and returns the initial template strings for all five core memory-bank markdown files, including timestamps.

  // Memory Bank file template generation function
  function getMemoryBankTemplates(): Record<string, string> {
    const timestamp = formatTimestamp();
  
    return {
      "productContext.md": `# Product Context
  
  This file provides a high-level overview of the project and the expected product that will be created. Initially it is based upon projectBrief.md (if provided) and all other available project-related information in the working directory. This file is intended to be updated as the project evolves, and should be used to inform all other modes of the project's goals and context.
  ${timestamp} - Log of updates made will be appended as footnotes to the end of this file.
  
  *
  
  ## Project Goal
  
  *   
  
  ## Key Features
  
  *   
  
  ## Overall Architecture
  
  *   `,
  
      "activeContext.md": `# Active Context
  
  This file tracks the project's current status, including recent changes, current goals, and open questions.
  ${timestamp} - Log of updates made.
  
  *
  
  ## Current Focus
  
  *   
  
  ## Recent Changes
  
  *   
  
  ## Open Questions/Issues
  
  *   `,
  
      "progress.md": `# Progress
  
  This file tracks the project's progress using a task list format.
  ${timestamp} - Log of updates made.
  
  *
  
  ## Completed Tasks
  
  *   
  
  ## Current Tasks
  
  *   
  
  ## Next Steps
  
  *   `,
  
      "decisionLog.md": `# Decision Log
  
  This file records architectural and implementation decisions using a list format.
  ${timestamp} - Log of updates made.
  
  *
  
  ## Decision
  
  *
  
  ## Rationale 
  
  *
  
  ## Implementation Details
  
  *   `,
  
      "systemPatterns.md": `# System Patterns *Optional*
  
  This file documents recurring patterns and standards used in the project.
  It is optional, but recommended to be updated as the project evolves.
  ${timestamp} - Log of updates made.
  
  *
  
  ## Coding Patterns
  
  *   
  
  ## Architectural Patterns
  
  *   
  
  ## Testing Patterns
  
  *   `,
    };
  }