Adds update direct function into MCP.

.cursor/rules/mcp.mdc

@@ -97,3 +97,91 @@ Follow these steps to add MCP support for an existing Task Master command (see [
 - `handleApiResult` uses `createContentResponse` or `createErrorResponse` internally.
 - `handleApiResult` also uses `processMCPResponseData` by default to filter potentially large fields (`details`, `testStrategy`) from task data. Provide a custom processor function to `handleApiResult` if different filtering is needed.
 - The final JSON response sent to the MCP client will include the `fromCache` boolean flag (obtained from the `*Direct` function's result) alongside the actual data (e.g., `{ "fromCache": true, "data": { ... } }` or `{ "fromCache": false, "data": { ... } }`).
+
+## Parameter Type Handling
+
+- **Prefer Direct Function Calls**: For optimal performance and error handling, MCP tools should utilize direct function wrappers defined in [`task-master-core.js`](mdc:mcp-server/src/core/task-master-core.js). These wrappers call the underlying logic from the core modules (e.g., [`task-manager.js`](mdc:scripts/modules/task-manager.js)).
+- **Standard Tool Execution Pattern**:
+    - The `execute` method within each MCP tool (in `mcp-server/src/tools/*.js`) should:
+        1.  Call the corresponding `*Direct` function wrapper (e.g., `listTasksDirect`) from [`task-master-core.js`](mdc:mcp-server/src/core/task-master-core.js), passing necessary arguments and the logger.
+        2.  Receive the result object (typically `{ success, data/error, fromCache }`).
+        3.  Pass this result object to the `handleApiResult` utility (from [`tools/utils.js`](mdc:mcp-server/src/tools/utils.js)) for standardized response formatting and error handling.
+        4.  Return the formatted response object provided by `handleApiResult`.
+- **CLI Execution as Fallback**: The `executeTaskMasterCommand` utility in [`tools/utils.js`](mdc:mcp-server/src/tools/utils.js) allows executing commands via the CLI (`task-master ...`). This should **only** be used as a fallback if a direct function wrapper is not yet implemented or if a specific command intrinsically requires CLI execution.
+- **Centralized Utilities** (See also: [`utilities.mdc`](mdc:.cursor/rules/utilities.mdc)):
+    - Use `findTasksJsonPath` (in [`task-master-core.js`](mdc:mcp-server/src/core/task-master-core.js)) *within direct function wrappers* to locate the `tasks.json` file consistently.
+    - **Leverage MCP Utilities**: The file [`tools/utils.js`](mdc:mcp-server/src/tools/utils.js) contains essential helpers for MCP tool implementation:
+        - `getProjectRoot`: Normalizes project paths.
+        - `handleApiResult`: Takes the raw result from a `*Direct` function and formats it into a standard MCP success or error response, automatically handling data processing via `processMCPResponseData`. This is called by the tool's `execute` method.
+        - `createContentResponse`/`createErrorResponse`: Used by `handleApiResult` to format successful/error MCP responses.
+        - `processMCPResponseData`: Filters/cleans data (e.g., removing `details`, `testStrategy`) before it's sent in the MCP response. Called by `handleApiResult`.
+        - `getCachedOrExecute`: **Used inside `*Direct` functions** in `task-master-core.js` to implement caching logic.
+        - `executeTaskMasterCommand`: Fallback for executing CLI commands.
+- **Caching**: To improve performance for frequently called read operations (like `listTasks`, `showTask`, `nextTask`), a caching layer using `lru-cache` is implemented.
+    - **Caching logic resides *within* the direct function wrappers** in [`task-master-core.js`](mdc:mcp-server/src/core/task-master-core.js) using the `getCachedOrExecute` utility from [`tools/utils.js`](mdc:mcp-server/src/tools/utils.js).
+    - Generate unique cache keys based on function arguments that define a distinct call (e.g., file path, filters).
+    - The `getCachedOrExecute` utility handles checking the cache, executing the core logic function on a cache miss, storing the result, and returning the data along with a `fromCache` flag.
+    - Cache statistics can be monitored using the `cacheStats` MCP tool (implemented via `getCacheStatsDirect`).
+    - **Caching should generally be applied to read-only operations** that don't modify the `tasks.json` state. Commands like `set-status`, `add-task`, `update-task`, `parse-prd`, `add-dependency` should *not* be cached as they change the underlying data.
+
+**MCP Tool Implementation Checklist**:
+
+1. **Core Logic Verification**:
+   - [ ] Confirm the core function is properly exported from its module (e.g., `task-manager.js`)
+   - [ ] Identify all required parameters and their types
+
+2. **Direct Function Wrapper**:
+   - [ ] Create the `*Direct` function in `task-master-core.js`
+   - [ ] Handle all parameter validations and type conversions
+   - [ ] Implement path resolving for relative paths
+   - [ ] Add appropriate error handling with standardized error codes
+   - [ ] Add to `directFunctions` map
+
+3. **MCP Tool Implementation**:
+   - [ ] Create new file in `mcp-server/src/tools/` with kebab-case naming
+   - [ ] Define zod schema for all parameters
+   - [ ] Implement the `execute` method following the standard pattern
+   - [ ] Register tool in `mcp-server/src/tools/index.js`
+
+4. **Testing**:
+   - [ ] Write unit tests for the direct function wrapper
+   - [ ] Write integration tests for the MCP tool
+
+## Standard Error Codes
+
+- **Standard Error Codes**: Use consistent error codes across direct function wrappers
+  - `INPUT_VALIDATION_ERROR`: For missing or invalid required parameters
+  - `FILE_NOT_FOUND_ERROR`: For file system path issues
+  - `CORE_FUNCTION_ERROR`: For errors thrown by the core function
+  - `UNEXPECTED_ERROR`: For all other unexpected errors
+
+- **Error Object Structure**:
+  ```javascript
+  {
+    success: false,
+    error: {
+      code: 'ERROR_CODE',
+      message: 'Human-readable error message'
+    },
+    fromCache: false
+  }
+  ```
+
+- **MCP Tool Logging Pattern**:
+  - ✅ DO: Log the start of execution with arguments (sanitized if sensitive)
+  - ✅ DO: Log successful completion with result summary
+  - ✅ DO: Log all error conditions with appropriate log levels
+  - ✅ DO: Include the cache status in result logs
+  - ❌ DON'T: Log entire large data structures or sensitive information
+
+- The MCP server integrates with Task Master core functions through three layers:
+  1. Tool Definitions (`mcp-server/src/tools/*.js`) - Define parameters and execute methods
+  2. Direct Function Wrappers (`task-master-core.js`) - Handle validation, path resolution, and caching
+  3. Core Logic Functions (various modules) - Implement actual functionality
+
+- This layered approach provides:
+  - Clear separation of concerns
+  - Consistent parameter validation
+  - Centralized error handling
+  - Performance optimization through caching (for read operations)
+  - Standardized response formatting