nestjs-dev-logs-mcp

# nestjs-dev-logs-mcp An MCP server that exposes NestJS development server logs to AI coding agents (Claude Code, Cursor, Codex). Reads log files produced by a NestJS dev server and provides structured, filterable access through 7 MCP tools. ## Setup ### 1. Pipe NestJS logs to a file ```bash # Option A: pipe via tee (keeps terminal output) nest start --watch 2>&1 | tee /tmp/nest-dev.log # Option B: redirect to file nest start --watch > /tmp/nest-dev.log 2>&1 ``` ### 2. Build the server ```bash npm install npm run build ``` ### 3. Configure your MCP client **Claude Code** (`~/.claude/claude_desktop_config.json` or project `.mcp.json`): ```json { "mcpServers": { "nestjs-logs": { "command": "node", "args": ["dist/index.js"], "cwd": "/path/to/nestjs-dev-logs-mcp", "env": { "NEST_LOG_PATH": "/tmp/nest-dev.log" } } } } ``` **Cursor** (`.cursor/mcp.json`): ```json { "mcpServers": { "nestjs-logs": { "command": "node", "args": ["/path/to/nestjs-dev-logs-mcp/dist/index.js"], "env": { "NEST_LOG_PATH": "/tmp/nest-dev.log" } } } } ``` ## Environment Variables | Variable | Default | Description | |----------|---------|-------------| | `NEST_LOG_PATH` | `/tmp/nest-dev.log` | Path to the NestJS log file | | `NEST_LOG_FORMAT` | `auto` | `auto`, `text`, or `json` | | `NEST_LOG_MAX_LINES` | `10000` | Max lines to scan per query | | `NEST_LOG_TAIL_BYTES` | `1048576` | Bytes to read from file end (1MB) | ## Tools ### `get_recent_errors` Get recent errors and exceptions from logs. - `since_minutes` — only errors from the last N minutes - `module` — filter by NestJS module name - `limit` — max errors to return (default 20, max 100) ### `get_request_logs` Get HTTP request logs. - `status_code` — filter by exact status code - `status_range` — filter by range: `2xx`, `3xx`, `4xx`, `5xx` - `path_pattern` — regex to match request paths - `method` — filter by HTTP method - `min_duration_ms` — only requests slower than N ms - `since_minutes`, `limit` ### `get_db_queries` Get database query logs (TypeORM, Prisma, Mongoose). - `min_duration_ms` — only slow queries - `failed_only` — only failed queries - `table_pattern` — regex to match table names - `since_minutes`, `limit` ### `get_di_errors` Get NestJS dependency injection resolution errors. - `since_minutes`, `limit` ### `tail_logs` Get the last N lines from the log file (escape hatch for raw access). - `lines` — number of lines (default 50, max 500) - `grep` — regex to filter lines ### `get_log_summary` Health check — counts by severity, top error patterns, status code distribution. - `since_minutes` ### `truncate_logs` Clear the log file. Uses file truncation (not deletion) so NestJS keeps writing. - `confirm` — must be `true` ## Supported Log Formats **NestJS text** (default logger): ``` [Nest] 12345 - 04/16/2026, 10:30:00 AM LOG [HTTP] GET /api/users 200 12ms ``` **nestjs-pino JSON** (recommended for full request data): ```json {"level":30,"time":1713254465000,"msg":"GET /api/users 200","req":{"method":"GET","url":"/api/users"},"res":{"statusCode":200},"responseTime":12} ``` Format is auto-detected by sampling lines. Use `NEST_LOG_FORMAT` to override. ## Development ```bash npm run dev # run with tsx (hot reload) npm test # vitest npm run test:watch # vitest --watch npm run build # tsc → dist/ ``` ## Multiple Log Files For multiple NestJS services, configure a separate MCP server entry per log file: ```json { "mcpServers": { "api-logs": { "command": "node", "args": ["dist/index.js"], "env": { "NEST_LOG_PATH": "/tmp/api-dev.log" } }, "worker-logs": { "command": "node", "args": ["dist/index.js"], "env": { "NEST_LOG_PATH": "/tmp/worker-dev.log" } } } } ```