You are managing remote Sprite VMs from a local machine using the sprite CLI. This skill covers the local-side CLI for controlling Sprites externally. (Sprites also have built-in agent context at /.sprite/docs/ for agents running *inside* the Sprite.)
Sprites are persistent, hardware-isolated Linux VMs on Fly.io with durable filesystems backed by object storage.
CLI Basics
The sprite CLI controls remote Sprites. The -s flag specifies which Sprite, -o specifies the org.
# List all sprites
sprite list
# Execute a command on a sprite (blocks until done)
sprite exec -s <name> -- <command>
# Open interactive shell
sprite console -s <name>
# Activate a sprite for the current directory (creates .sprite file)
sprite use <name>When a .sprite file exists in the working directory, -s can be omitted.
Executing Commands
sprite exec is the primary tool for remote work. Stdout and stderr are returned to the local terminal.
# Run a single command
sprite exec -s mysprite -- ls -la /home/sprite
# Run a multi-part command (quote or use --)
sprite exec -s mysprite -- bash -c "cd /project && npm test"
# Pipe output locally
sprite exec -s mysprite -- cat /path/to/file > local-copy.txtImportant: Each sprite exec invocation is a separate session. Environment variables, working directory, and shell state do not persist between calls. For stateful work, use bash -c "..." to chain commands, or use sprite console for interactive sessions.
File Transfer
There is no dedicated file transfer command. Use sprite exec with cat for pulling files, or pipe content in:
# Pull a file from a sprite
sprite exec -s mysprite -- cat /path/on/sprite > local-file.txt
# Pull a binary file
sprite exec -s mysprite -- base64 /path/to/binary | base64 -d > local-file.bin
# Push a file to a sprite (via stdin)
cat local-file.txt | sprite exec -s mysprite -- bash -c "cat > /path/on/sprite"
# For heavier file work, use SSHFS via proxy
sprite proxy 2222 # then sshfs sprite@localhost:/home/sprite /mnt/sprite -p 2222Checkpoints
Checkpoints capture the writable overlay of the Sprite's filesystem. They are fast (sub-second, copy-on-write) and cheap.
# Create a checkpoint (with optional comment)
sprite checkpoint create -s mysprite
sprite checkpoint create -s mysprite -m "before risky refactor"
# List checkpoints
sprite checkpoint list -s mysprite
# Restore to a checkpoint (destructive — drops current session and all changes since)
sprite restore <checkpoint-id> -s myspriteCheckpoint aggressively. Before any risky operation, before switching contexts, whenever something is working. Checkpoints are nearly free.
The last 5 checkpoints are also mounted inside the Sprite at /.sprite/checkpoints/ for direct file-level inspection without restoring.
Networking
Each Sprite gets a public HTTPS URL at https://<name>-<org>.sprites.dev/, routing to port 8080 by default.
# Show the sprite's URL and auth mode
sprite url -s mysprite
# Make the URL public (no auth required)
sprite url update --auth public -s mysprite
# Restore authenticated mode
sprite url update --auth default -s mysprite
# Forward remote ports to local machine
sprite proxy 8080 3000 -s myspriteNetwork egress policy is managed via the Sprites REST API, not the CLI:
# View current network policy (from inside the sprite)
sprite exec -s mysprite -- cat /.sprite/policy/network.json
# Update network policy (from outside, via API)
sprite api -s mysprite POST /policy/network \
-d '{"rules": [{"include": "defaults"}, {"domain": "custom-api.com", "action": "allow"}]}'Network policy can only be modified externally. The Sprite cannot change its own policy.
Services
Services are long-running processes inside a Sprite that persist across reboots and hibernation.
# List services
sprite exec -s mysprite -- sprite-env services list
# Create a service
sprite exec -s mysprite -- sprite-env services create <name> --cmd <binary> --args "<args>"
# Get service status
sprite exec -s mysprite -- sprite-env services get <name>
# View service logs
sprite exec -s mysprite -- cat /.sprite/logs/services/<name>.stderr.logOne service can be designated as the HTTP service (receives proxied requests on the Sprite's URL).
Multi-Sprite Coordination
When working across multiple Sprites, use sprite list to see the fleet, then target each by name:
# Run the same command across all sprites
for s in $(sprite list); do
echo "=== $s ==="
sprite exec -s "$s" -- <command>
doneEach Sprite is fully isolated — no shared mutable state. Coordinate through explicit communication: files in shared Tigris buckets, HTTP endpoints, or Git repos.
Lifecycle
# Create a new sprite
sprite create <name>
sprite create -o <org> <name>
# Destroy a sprite (irreversible)
sprite destroy <name>Sprites auto-sleep when idle (no active commands, TCP connections, TTY sessions, or running Services). They wake automatically on the next sprite exec, sprite console, or HTTP request to their URL. Anything on disk persists across sleep cycles. Running processes do not — use Services for daemons.
Internal Sprite Paths
When running commands on a Sprite, these paths are useful:
/.sprite/api.sock— internal API Unix socket/.sprite/policy/network.json— read-only network policy/.sprite/checkpoints/— last 5 checkpoints mounted for inspection/.sprite/logs/services/— service logs/.sprite/docs/— platform documentation (agent-context.md, languages.md, docker.md)/home/sprite/— user home directory