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

# 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

npm install
npm run build

3. Configure your MCP client

Claude Code (~/.claude/claude_desktop_config.json or project .mcp.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):

{
  "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):

{"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

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:

{
  "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" }
    }
  }
}