Cross-platform MCP server for managing long-lived background processes from any MCP client
Connect Runs on your machine
claude mcp add mcp-sidecar -e SIDECAR_MAX_PROCESSES=<SIDECAR_MAX_PROCESSES> -e SIDECAR_BUFFER_SIZE=<SIDECAR_BUFFER_SIZE> -e SIDECAR_KILL_TIMEOUT=<SIDECAR_KILL_TIMEOUT> -e SIDECAR_CLEANUP_AFTER=<SIDECAR_CLEANUP_AFTER> -e SIDECAR_MAX_OUTPUT_SIZE=<SIDECAR_MAX_OUTPUT_SIZE> -e SIDECAR_ALLOWED_EXECUTABLES=<SIDECAR_ALLOWED_EXECUTABLES> -e SIDECAR_BLOCKED_PATTERNS=<SIDECAR_BLOCKED_PATTERNS> -e SIDECAR_AUDIT_LOG=<SIDECAR_AUDIT_LOG> -- npx -y [email protected]{
"mcpServers": {
"mcp-sidecar": {
"command": "npx",
"args": [
"-y",
"[email protected]"
],
"env": {
"SIDECAR_MAX_PROCESSES": "<SIDECAR_MAX_PROCESSES>",
"SIDECAR_BUFFER_SIZE": "<SIDECAR_BUFFER_SIZE>",
"SIDECAR_KILL_TIMEOUT": "<SIDECAR_KILL_TIMEOUT>",
"SIDECAR_CLEANUP_AFTER": "<SIDECAR_CLEANUP_AFTER>",
"SIDECAR_MAX_OUTPUT_SIZE": "<SIDECAR_MAX_OUTPUT_SIZE>",
"SIDECAR_ALLOWED_EXECUTABLES": "<SIDECAR_ALLOWED_EXECUTABLES>",
"SIDECAR_BLOCKED_PATTERNS": "<SIDECAR_BLOCKED_PATTERNS>",
"SIDECAR_AUDIT_LOG": "<SIDECAR_AUDIT_LOG>"
}
}
}
}{
"mcpServers": {
"mcp-sidecar": {
"command": "npx",
"args": [
"-y",
"[email protected]"
],
"env": {
"SIDECAR_MAX_PROCESSES": "<SIDECAR_MAX_PROCESSES>",
"SIDECAR_BUFFER_SIZE": "<SIDECAR_BUFFER_SIZE>",
"SIDECAR_KILL_TIMEOUT": "<SIDECAR_KILL_TIMEOUT>",
"SIDECAR_CLEANUP_AFTER": "<SIDECAR_CLEANUP_AFTER>",
"SIDECAR_MAX_OUTPUT_SIZE": "<SIDECAR_MAX_OUTPUT_SIZE>",
"SIDECAR_ALLOWED_EXECUTABLES": "<SIDECAR_ALLOWED_EXECUTABLES>",
"SIDECAR_BLOCKED_PATTERNS": "<SIDECAR_BLOCKED_PATTERNS>",
"SIDECAR_AUDIT_LOG": "<SIDECAR_AUDIT_LOG>"
}
}
}
}{
"servers": {
"mcp-sidecar": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"[email protected]"
],
"env": {
"SIDECAR_MAX_PROCESSES": "<SIDECAR_MAX_PROCESSES>",
"SIDECAR_BUFFER_SIZE": "<SIDECAR_BUFFER_SIZE>",
"SIDECAR_KILL_TIMEOUT": "<SIDECAR_KILL_TIMEOUT>",
"SIDECAR_CLEANUP_AFTER": "<SIDECAR_CLEANUP_AFTER>",
"SIDECAR_MAX_OUTPUT_SIZE": "<SIDECAR_MAX_OUTPUT_SIZE>",
"SIDECAR_ALLOWED_EXECUTABLES": "<SIDECAR_ALLOWED_EXECUTABLES>",
"SIDECAR_BLOCKED_PATTERNS": "<SIDECAR_BLOCKED_PATTERNS>",
"SIDECAR_AUDIT_LOG": "<SIDECAR_AUDIT_LOG>"
}
}
}
}Replace the values in angle brackets with your own. Keys stay on your machine; we never see them.
Tools
This server runs locally, so its tools are listed by your MCP client once it starts.
Environment variables
| Name | Description |
|---|---|
SIDECAR_MAX_PROCESSESOptional | Maximum number of concurrent managed processes (default: 10) |
SIDECAR_BUFFER_SIZEOptional | Output buffer size per stream in bytes (default: 1048576) |
SIDECAR_KILL_TIMEOUTOptional | Milliseconds to wait between graceful and forced termination (default: 5000) |
SIDECAR_CLEANUP_AFTEROptional | Seconds before exited processes are auto-removed. 0 disables cleanup (default: 1800) |
SIDECAR_MAX_OUTPUT_SIZEOptional | Global cap on bytes returned by the output tool. 0 means unlimited (default: 0) |
SIDECAR_ALLOWED_EXECUTABLESOptional | Comma-separated allowlist of executable names. When set, enables security mode with direct exec (no shell). Unset means security disabled. |
SIDECAR_BLOCKED_PATTERNSOptional | Comma-separated regex patterns to reject in commands. Only applies when security is enabled. |
SIDECAR_AUDIT_LOGOptional | Audit log destination. 'true' writes to cwd, 'temp' writes to OS temp dir, or a directory path. Unset disables audit logging. |
Details
| Package | [email protected] (NPM, stdio) |
| First published | 2 Jun 2026 |
| Last updated | 2 Jun 2026 |
| Registry name | io.github.lsequeiraa/mcp-sidecar |
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