Error after stopping server and starting again

[Jakob-Gliwa]

Hi there,

thank you for your great work. I'm trying to get the mcp server to run.
Managed it once but after closing it I get the following error message:

(base) mcp-loxone % cargo run --bin loxone-mcp-server stdio
warning: loxone-mcp-rust@0.6.0: Created post-build-sign.sh - run this after building to sign the binary
warning: loxone-mcp-rust@0.6.0: macOS detected: Use './cargo-build-sign.sh' or 'make build' for automatic code signing
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 3.16s
     Running `target/debug/loxone-mcp-server stdio`
2025-08-04T15:14:47.348768Z  INFO loxone_mcp_server: 🚀 Starting Loxone MCP Server v0.6.0
2025-08-04T15:14:47.348839Z  INFO loxone_mcp_server: 🔑 Using direct CLI credentials
2025-08-04T15:14:47.350178Z  WARN pulseengine_mcp_auth::crypto::keys: Generated new master key. Set PULSEENGINE_MCP_MASTER_KEY=XXXXXXXXXXXXXX-XXXXXXXXXXXXXXXx for persistence
Error: Config("Storage error: Encryption error: Decryption failed: aead::Error")

Also - any chance to get a ready-to-use docker image ;) ?

[avrabe]

Hi @Jakob-Gliwa,

This error occurs because the server generates a new master key on each startup. When you restart, it can't decrypt credentials that were encrypted with the previous key.

Solution: Set the master key as an environment variable to persist it:

# Copy the PULSEENGINE_MCP_MASTER_KEY from the warning message and export it:
export PULSEENGINE_MCP_MASTER_KEY=<your-key-from-the-warning>

# Then run the server
cargo run --bin loxone-mcp-server stdio

Alternative - Use Credential ID (Recommended):
The newer credential system avoids this issue:

# Store credentials (one-time setup)
cargo run --bin loxone-mcp-auth store --name "Home" --host 192.168.1.100 --username admin --password your-password

# This will output a credential ID like: abc123def-456-789

# Use the credential ID to run the server
cargo run --bin loxone-mcp-server stdio --credential-id abc123def-456-789

Docker Image: There's a Dockerfile in the repo. You can build with:

docker build -t loxone-mcp:latest .
docker run -e LOXONE_HOST=<your-miniserver-ip> -e LOXONE_USER=<username> -e LOXONE_PASS=<password> loxone-mcp:latest

Let me know if you need further assistance!

[avrabe]

Update/Correction: The Docker instructions I provided won't work currently - the Dockerfile needs updating for Rust 1.85 (2024 edition requirement).

For now, the recommended approach is:

1. Use environment variables directly:

   export LOXONE_HOST=192.168.1.100
   export LOXONE_USER=admin
   export LOXONE_PASS=your-password
   cargo run --bin loxone-mcp-server stdio

2. Or use the credential ID system:

   cargo run --bin loxone-mcp-auth store --name "Home" --host 192.168.1.100 --username admin --password your-password
   # Use the output credential ID
   cargo run --bin loxone-mcp-server stdio --credential-id <your-id>

The encryption key error you saw is from the pulseengine-mcp dependency's internal credential storage. Using env vars or the credential-id approach should avoid that issue.

[avrabe]

Good news - just pushed a fix for the Dockerfile (now uses Rust 1.85). Docker build should work now:

docker build -t loxone-mcp:latest .
docker run -e LOXONE_HOST=<your-miniserver-ip> -e LOXONE_USER=<username> -e LOXONE_PASS=<password> loxone-mcp:latest