<!-- mcp-name: io.github.kascada/logmcp -->

LogMCP

MCP server — read-only log access for AI assistants. Debug your Linux server with AI, without giving the AI shell access.

No SSH. No write permissions. The AI reads your logs over HTTPS and helps you diagnose problems, while your server stays fully under your control.

LogMCP is an open-source MCP server that exposes log files on a remote Linux server to AI assistants (Claude Code, VS Code, Claude Desktop). Access is read-only, token-authenticated, and fully audited via syslog.

Get Started

Option A: Quickstart (no root required)

Try LogMCP in under a minute — no config file, no root, no systemd:

logmcp quickstart

The command checks your group memberships (adm, systemd-journal), generates a bearer token and a self-signed TLS certificate, starts the server, and prints a ready-to-paste claude mcp add command.

Running as root? Pass --user <name> and LogMCP will add the user to the required groups and re-launch as that user — root is not needed for future starts.

Note: Token and certificate are ephemeral. The token changes on every start. For a permanent setup use Option B.

logmcp quickstart --port 7789 --token mytoken   # optional flags

After testing, remove the server from Claude Code:

claude mcp remove logmcp-quickstart

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Option B: Permanent installation (recommended)

1. Install

go install github.com/kascada/logmcp@latest

Or install the pre-built .deb (replace x.y.z with the latest version):

curl -LO https://github.com/kascada/logmcp/releases/download/vx.y.z/logmcp_x.y.z_amd64.deb
sudo dpkg -i logmcp_x.y.z_amd64.deb

2. Run the setup wizard

sudo logmcp setup

Guides you through TLS mode, bearer token, and systemd service — then prints a ready-to-paste client config snippet.

3. Add to your AI client

logmcp client-config claude-code   # or: vscode | claude-desktop

Paste the output into your MCP client config. Done — your AI can now read the server's logs.

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The Key Advantage: Let the AI Debug Without Touching Your Server

You give the AI a read-only window into your logs. That's it.

• No SSH access required — the AI connects like any HTTPS client
• No write permissions — the AI cannot change, delete, or execute anything
• No shell access — not even read access beyond the whitelisted log paths
• Works from anywhere — your laptop, Claude Desktop, a remote CI agent
• Every access is audited via syslog on the server

This makes LogMCP ideal for situations where you need AI-assisted debugging but cannot or do not want to grant shell access: production servers, customer machines, hardened environments, or any setup where least-privilege matters.

SSH is also supported. If your AI client is Claude Code running locally with an SSH key, you can use LogMCP over an SSH tunnel instead of a public HTTPS endpoint. See SSH Tunnel Setup below.

Features

• Read-only access to log files — the AI cannot modify anything
• Whitelist/blacklist glob patterns for fine-grained access control
• systemd journal (journald://) as a virtual log source
• Multi-token auth — per-client bearer tokens with revocation
• External authenticator support — delegate token verification to any CLI program
• TLS support: self-signed, custom cert, or behind Caddy reverse proxy
• Audit trail via syslog (access only, no log content)
• Guided interactive setup wizard
• Systemd service integration
• Extensions — expose external CLI tools or Redis-RPC workers as additional MCP tools
• Macros — define composite MCP tools as YAML files, no code required
• fail2ban integration and in-process rate limiting

Setup Details

The wizard (sudo logmcp setup) covers:

• Deployment mode (direct TLS or behind Caddy)
• Port and bearer token configuration
• Systemd service installation
• Client configuration snippets for Claude Code, VS Code, and Claude Desktop

Whitelist/blacklist and journald are configured directly in /etc/logmcp/config.yaml after setup.

Environment variable substitution

Any value in config.yaml can reference environment variables using ${VAR} or $VAR syntax. The substitution happens before the file is parsed, so it works everywhere — tokens, paths, DSNs, etc.

auth:
  tokens:
    - name: claude
      token: ${LOGMCP_TOKEN}
      scopes: [read]

extensions:
  clitool:
    - name: switchboard
      command: /usr/local/bin/switchboard
      timeout_seconds: 10

Unset variables expand to an empty string. To keep a literal $ in a value, use $$.

After setup, start the server:

sudo systemctl start logmcp

Commands

Command	Description
logmcp serve	Start the MCP server (default)
logmcp quickstart	Start instantly without config file (no root required)
logmcp setup	Interactive setup wizard
logmcp check	Verify configuration and environment
logmcp token list	List configured bearer tokens
logmcp token add --name <n>	Add a new bearer token
logmcp token remove <name>	Remove a bearer token
logmcp token renew <name>	Generate a new value for an existing token
logmcp logs list	List accessible log files
logmcp logs read <path>	Read a log file or journald://
logmcp logs search <path>	Search a log file or journald://
logmcp logs info <path>	Show log file metadata
logmcp service install	Install systemd service
logmcp service remove	Remove systemd service
logmcp service status	Show service status
logmcp service caddy-snippet	Print Caddyfile configuration
logmcp client-config claude-code	Print Claude Code MCP config
logmcp client-config vscode	Print VS Code MCP config
logmcp client-config claude-desktop	Print Claude Desktop MCP config
logmcp security install-fail2ban	Install fail2ban filter and jail for logmcp

MCP Tools

These are the tools LogMCP exposes to AI assistants:

Tool	Description
list_logs	List all log files the server has been configured to expose
read_log	Read lines from a log file — head, tail, offset, or time window
search_log	Search a log file by regexp with optional context lines and time filter
log_info	File metadata: size, line count, last modified
check_environment	Server-side health checks (config, TLS, whitelist, syslog, databases)
check_config	Show current server configuration and optional parameters at their defaults
server_status	Runtime status of the MCP layer and registered extensions

Extensions may add further tools — their names are prefixed with the extension name (e.g. myapp_status for an extension named myapp).

Extensions — Wrapping External Tools as MCP

LogMCP can expose any external program or service as additional MCP tools — no custom MCP server required. The AI sees them alongside the built-in log tools.

CLI extension

Any program that implements the clitool interface (list / call subcommands) can be registered. LogMCP calls <command> list at startup to discover tools, and forwards each tool call to <command> call <tool> --token-stdin.

extensions:
  clitool:
    - name: myapp
      command: /usr/local/bin/myapp-ctl
      timeout_seconds: 10

This spawns a subprocess per call — suitable for any program on the same or a remote host.

RPC extension (Redis)

For programs running on the same host, the RPC variant avoids the per-call process-startup overhead (relevant for Python programs where interpreter startup and imports add noticeable latency). Instead of spawning a subprocess, LogMCP pushes a request onto a Redis list and waits for the worker's reply.

extensions:
  clitool:
    - name: myapp
      command: /usr/local/bin/myapp-ctl   # still used for `list` at startup
      mode: rpc
      redis_addr: "127.0.0.1:6379"
      timeout_seconds: 5

The worker reads requests from a Redis list and pushes its reply to a per-request reply key. See docs/RPC.md for the full protocol.

Auth flow

The bearer token from each incoming MCP request is forwarded to the extension — either via stdin (CLI mode) or as caller metadata in the RPC envelope. The extension can verify it or trust the pre-resolved identity.

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Case Studies

Real-world scenarios where LogMCP makes the difference — see docs/case-studies.md:

• Asterisk/VoIP — Paket-Kompilierung und Abhängigkeitsfehler debuggen
• Webserver mit Caddy Reverse Proxy — produktive Installation
• Standalone-Betrieb mit eigenem TLS

SSH Tunnel Setup

If you are using Claude Code locally and already have SSH access to the server, you can run LogMCP without a public HTTPS endpoint:

# Forward remote port 7788 to localhost
ssh -L 7788:127.0.0.1:7788 user@yourserver

# Then point your MCP client at https://localhost:7788

LogMCP still requires a bearer token over the tunnel — the SSH layer adds transport security, the token controls which client can connect.

License

MIT License — see LICENSE.