Configuration

Environment variables and sandbox-policy.yaml for processd-mcp and the sandbox manager.

Two files matter on a Linux binary install:

File	Role
`/etc/processd-mcp/processd-mcp.env`	Process environment. systemd `EnvironmentFile`.
Policy YAML (optional)	Kernel sandbox. Path in `MCP_SANDBOX_POLICY_FILE`.

The desktop app writes the same YAML schema through the GUI. The manager image is configured with PROCESSD_MANAGER_* env vars in compose.

There is no hot reload. Change env or YAML, then restart the process.

Kernel environment

The installer creates /etc/processd-mcp/processd-mcp.env mode 600:

MCP_HOST=127.0.0.1
MCP_PORT=8080
PROCESSD_TOKEN=<random hex>

Variable	Default	Meaning
`MCP_HOST`	`0.0.0.0` without the installer; installer sets `127.0.0.1`	Bind address. See Linux binary.
`MCP_PORT`	`8080`	Listen port.
`PROCESSD_TOKEN`	unset (no auth)	Value of `X-Access-Token`. Always set this.
`MCP_SANDBOX_POLICY_FILE`	unset (no kernel sandbox)	Absolute path to policy YAML.
`MCP_SANDBOX_RUNTIME_DIR`	`$TMPDIR/processd-mcp/sandbox`	Helper runtime dir.
`MCP_DEFAULT_SHELL`	`$SHELL` or `/bin/bash`	Shell for `Bash`.
`MCP_ALLOW_ESCALATED`	`false`	Break-glass: skip sandbox for shell tools. Keep `false` in production.
`MCP_ALLOW_LOGIN_SHELL`	`true`	Login shell for `Bash`.
`MCP_BASH_DEFAULT_TIMEOUT_MS`	`120000`	Default `Bash` timeout.
`MCP_BASH_MAX_TIMEOUT_MS`	`600000`	Hard max timeout.
`MCP_WEB_FETCH_DEFAULT_TIMEOUT_MS`	`30000`	`WebFetch` timeout.
`MCP_WEB_FETCH_DEFAULT_MAX_BYTES`	`2 MiB`	`WebFetch` body cap.

PROCESSD_ENV_* copies into the command environment (prefix stripped). Example: PROCESSD_ENV_TERM=linux becomes TERM=linux inside Bash.

Edit the env file, then:

sudo systemctl restart processd-mcp

See Sandbox policy for the full schema and a worked example.

Compose sets these on processd-sandbox-manager. The important ones:

Variable	Typical	Meaning
`PROCESSD_MANAGER_HOST` / `PORT`	`0.0.0.0` / `18080`	Manager HTTP API (compose network). Clients talk to the scheduler on `:18081`.
`PROCESSD_MANAGER_PUBLIC_MCP_HOST`	LAN or Tailscale IP, not `0.0.0.0`	Host clients use to reach sandbox MCP workers.
`PROCESSD_MANAGER_PUBLIC_BASE_URL`	`http://127.0.0.1:18080`	Base URL returned by the manager. Scheduler rewrites this to its own `public_base_url`.
`PROCESSD_MANAGER_LIMITS_MODE`	`required` in release compose	Fail sandbox create if cgroups cannot apply.
`PROCESSD_MANAGER_SANDBOX_TTL_SECONDS`	`3600`	Idle sandbox lifetime.

Cluster walkthrough: Sandbox cluster.