MCP Redis Diagnostics

MCP server for Redis diagnostics — analyze memory usage, slowlog, client connections, and keyspace health with AI-powered recommendations.

Why This Tool?

Most Redis MCP servers are CRUD wrappers (get/set keys). RedisNexus offers diagnostics but targets enterprises (K8s, multi-tenant SaaS). This tool is the only lightweight npm package for deep Redis diagnostics — 7 tools covering memory fragmentation, slowlog patterns, client connection health, keyspace distribution, latency analysis, and configuration auditing. Install with npx, no Docker or SaaS required.

Pro Tier

Generate exportable diagnostic reports (HTML + PDF) with a Pro license key.

• Full JVM thread dump analysis report with actionable recommendations
• PDF export for sharing with your team
• Priority support

$9.00/month — Get Pro License

Pro license key activates the generate_report MCP tool in mcp-jvm-diagnostics.

Tools (7)

analyze_memory

Analyze Redis memory usage and fragmentation.

Detects:

• High memory fragmentation (>1.5x RSS/used ratio)
• Swap risk (fragmentation <1.0)
• Maxmemory pressure (approaching limit)
• Eviction patterns
• Missing maxmemory configuration
• Unsafe noeviction policy

analyze_slowlog

Analyze Redis SLOWLOG for slow commands.

Parameters:

• count (number, default: 128) — Number of slowlog entries to retrieve

Detects:

• Dangerous O(N) commands: KEYS, SMEMBERS, HGETALL, SORT
• High latency commands (>10ms, >100ms thresholds)
• Command concentration patterns
• Full slowlog buffer (missing history)

analyze_clients

Analyze Redis client connections.

Detects:

• Blocked clients (BLPOP/BRPOP)
• Connection pool saturation (>80% maxclients)
• Idle connections (>5 minutes)
• Large output buffer memory
• Pub/sub subscriber patterns

analyze_keyspace

Analyze Redis keyspace distribution and cache effectiveness.

Detects:

• Low TTL coverage (<20% of keys)
• Low cache hit rate (<80%)
• Unbalanced database distribution
• High expiry/eviction rates
• Multiple database anti-pattern

analyze_latency

Analyze Redis latency events from the LATENCY subsystem.

Detects:

• Fork latency spikes (RDB/AOF background save blocking operations)
• AOF fsync delays and write latency
• Slow command processing (O(1) commands unexpectedly slow)
• Eviction and key expiry cycle delays
• Active defragmentation impact
• Increasing latency trends over time

Requires latency-monitor-threshold to be set in redis.conf (e.g., CONFIG SET latency-monitor-threshold 100).

analyze_config

Analyze Redis configuration for security and reliability risks.

Detects:

• No maxmemory limit (unbounded memory growth, OOM risk)
• Unsafe eviction policy (noeviction causing errors at memory limit)
• Network exposure (bind 0.0.0.0 without protected-mode)
• Missing authentication (no requirepass)
• Disabled persistence (both AOF and RDB off — data loss on restart)
• Idle connection accumulation (timeout 0)
• Disabled TCP keepalive (dead connections undetected)
• Low server frequency (hz < 10 slowing background tasks)

analyze_performance

Comprehensive health assessment — runs all analyzers and produces a unified report.

Parameters:

• slowlog_count (number, default: 128) — Number of slowlog entries

Installation

npm install -g mcp-redis-diagnostics

Or run directly:

npx mcp-redis-diagnostics

Configuration

Environment Variables

Claude Desktop

Add to claude_desktop_config.json:

{
  "mcpServers": {
    "redis-diagnostics": {
      "command": "npx",
      "args": ["-y", "mcp-redis-diagnostics"],
      "env": {
        "REDIS_URL": "redis://localhost:6379"
      }
    }
  }
}

Redis with password:

{
  "env": {
    "REDIS_URL": "redis://:yourpassword@localhost:6379"
  }
}

Quick Demo

Once configured, try these prompts in Claude:

1. "Analyze my Redis memory usage — is there fragmentation?" — Shows used vs max memory, fragmentation ratio, eviction policy, and memory pressure issues
2. "Check the Redis slowlog for dangerous commands" — Identifies O(N) commands like KEYS/SMEMBERS, high-latency patterns, and optimization suggestions
3. "Run a complete Redis health check" — Unified report combining memory, slowlog, clients, keyspace, and latency analysis

"What's my cache hit rate? Are my TTLs configured properly?"

"Give me a full Redis health check"

Part of the MCP Java Backend Suite

This tool is part of a suite of MCP servers for backend developers:

• mcp-db-analyzer — PostgreSQL/MySQL/SQLite schema analysis
• mcp-jvm-diagnostics — Thread dump and GC log analysis
• mcp-migration-advisor — Flyway/Liquibase migration risk analysis
• mcp-spring-boot-actuator — Spring Boot health and metrics analysis
• mcp-redis-diagnostics — Redis memory, slowlog, and client diagnostics

Limitations & Known Issues

• Single Redis instance: Analyzes one Redis instance at a time. Does not support Redis Cluster topology discovery or Sentinel failover analysis.
• ACL restrictions: Some tools require specific Redis commands (SLOWLOG, CLIENT LIST, LATENCY). Redis ACLs may block these. The analyze_performance unified tool handles partial failures gracefully.
• Latency monitoring: The analyze_latency tool requires latency-monitor-threshold to be set in redis.conf. Without it, no latency events are captured.
• Key-level analysis: Keyspace analysis uses INFO keyspace aggregates. Individual key inspection (e.g., finding the largest keys) requires MEMORY USAGE per key, which is not performed to avoid impacting production.
• Redis Cluster: No cluster-specific analysis (slot distribution, rebalancing, cross-node latency). Works against individual nodes only.
• Redis Modules: Module-specific commands and data types (RedisJSON, RediSearch, RedisTimeSeries) are not analyzed.
• Memory advisor: Memory recommendations are based on INFO memory stats. For detailed memory breakdown by key type, use redis-cli --bigkeys externally.
• Fragmentation ratio: Memory fragmentation uses RSS vs. used memory ratio, which can be distorted by jemalloc. Values <1.0 may not always indicate swapping.
• Read-only: All commands are read-only (INFO, SLOWLOG GET, CLIENT LIST, LATENCY). No data or configuration is modified.

License

MIT