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Varun Pratap Bhardwaj edited this page Apr 8, 2026 · 1 revision

Configuration

SLM Mesh works with zero configuration. All settings have sensible defaults.

Environment Variables

Variable Default Description
SLM_MESH_PORT 7899 Broker HTTP port. If busy, tries next ports up to +10.
SLM_MESH_DATA_DIR ~/.slm-mesh/ Data directory for database, PID file, token, logs, sockets.
SLM_MESH_HOST 127.0.0.1 Broker bind address. Only 127.0.0.1, localhost, and ::1 are allowed.
SLM_MESH_HEARTBEAT_MS 15000 How often MCP servers send heartbeats (milliseconds).
SLM_MESH_STALE_MS 30000 Time without heartbeat before a peer is marked stale.
SLM_MESH_DEAD_MS 60000 Time without heartbeat before a stale peer is removed.
SLM_MESH_LOCK_TTL_MIN 10 Default lock expiration (minutes).

Data Directory Structure

~/.slm-mesh/
├── mesh.db          # SQLite database (WAL mode)
├── mesh.db-wal      # WAL journal (auto-managed)
├── mesh.db-shm      # Shared memory (auto-managed)
├── broker.pid       # Broker process ID
├── port             # Actual port (if different from default)
├── broker.token     # Bearer auth token (0o600 permissions)
├── broker.log       # Broker log output
└── peers/           # UDS socket files (one per peer)
    ├── <uuid>.sock
    └── ...

SQLite Configuration

Setting Value Purpose
Journal mode WAL Concurrent readers + single writer
Busy timeout 5000ms Wait for locks instead of failing
Cache size 64MB In-memory page cache
Journal size limit 64MB Prevent unbounded WAL growth
mmap size 128MB Memory-mapped I/O for reads

Tuning for High-Peer Scenarios

If running many concurrent sessions (20+):

  • Increase SLM_MESH_HEARTBEAT_MS to 30000 to reduce broker load
  • The SQLite WAL mode handles concurrent reads efficiently
  • Message TTL cleanup runs every heartbeat interval (prunes messages >24h, events >48h)
  • Each peer uses one UDS connection (~negligible memory)

Port Conflict Resolution

If port 7899 is busy, the broker tries ports 7900, 7901, ..., up to 7909. The actual port is written to ~/.slm-mesh/port so MCP servers and CLI can discover it.

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