55f5d6b629
* fix(sandbox): clamp a negative start_line in provider read_file LocalSandbox.read_file clamps the start line with max(start_line or 1, 1), but e2b, OpenSandbox and BoxLite used start_line or 1, so a negative value reached Python's negative-index slicing and read from the end of the file instead of the first line. Clamp all three the same way, and pin the boundary cases in their existing range tests: a past-EOF start still returns an empty string, a negative start reads from line 1. Surfaced by the review of #5616 (e2b has the same gap, consistency nit). * fix(sandbox): clamp negative end_line across providers Complete the range-bound consistency fix for e2b, OpenSandbox and BoxLite: clamp a negative end_line to zero like LocalSandbox instead of letting Python's negative-index slicing silently drop trailing lines. Add the symmetric boundary assertion to each provider's existing range test.
BoxLite backend
Runs each DeerFlow sandbox as a BoxLite micro-VM — a daemonless, OCI-native VM with its own kernel (libkrun/KVM on Linux, Hypervisor.framework on macOS). Motivated by the resource/cold-start pain with the default AIO Docker sandbox in #3439 and #3213; discussion in #3936.
Configuration
sandbox:
use: deerflow.community.boxlite:BoxliteProvider
image: python:3.12-slim # any OCI image (default: python:3.12-slim)
memory_mib: 1024 # per-box memory cap (optional)
cpus: 2 # per-box vCPUs (optional)
replicas: 3 # active + warm VM cap per gateway process (default: 3)
idle_timeout: 600 # warm VM idle seconds before stop; 0 disables
health_check_skip_seconds: 0.0 # optional low-latency mode: skip reclaim
# health checks for recent releases; 0 keeps
# reliability-first validation (default: 0.0)
environment: # injected into every command
PYTHONUNBUFFERED: "1"
Install the optional runtime before selecting this provider:
pip install "deerflow-harness[boxlite]"
The boxlite package is an optional DeerFlow harness extra, not part of the
default install. It is also limited to the host platforms and architectures
where BoxLite publishes wheels and can boot micro-VMs. Unsupported development
hosts, such as Windows, should use another sandbox provider or run DeerFlow from
a supported Linux/macOS environment.
Host requirement: BoxLite boots micro-VMs, so a Linux host needs KVM — i.e. nested virtualization when DeerFlow runs inside a cloud VM. macOS uses Hypervisor.framework. This is the main deployment constraint to weigh vs. the container-based providers.
Design
DeerFlow's Sandbox contract is synchronous; BoxLite's SDK is async-native and
its box handles are event-loop-affine. The provider owns one private asyncio
loop on a daemon thread and marshals every coroutine onto it via
run_coroutine_threadsafe. BoxLite boxes are named deterministically from
user_id:thread_id, released into an in-process warm pool after each agent turn,
and reclaimed by the same thread on the next acquire.
| File | Role |
|---|---|
provider.py |
SandboxProvider lifecycle + the private-loop bridge |
box.py |
Sandbox adapter; execute_command + file ops |
Contract coverage
The full Sandbox surface is implemented. File operations run as shell commands
inside the box and reuse deerflow.sandbox.search, mirroring e2b_sandbox:
execute_command—sh -lc, with per-call env and timeout.read_file/write_file/update_file—catand chunkedbase64(binary-safe, no arg-size limit).download_file— 100 MB cap, restricted to the/mnt/user-dataprefix.list_dir/glob/grep—find/grepwith busybox-portable flags; results filtered/capped in Python.
The provider creates /mnt/user-data/{workspace,uploads,outputs} and
/mnt/skills on box start so those virtual paths resolve natively.
Warm-pool capacity is governed by sandbox.replicas across active + warm VMs.
sandbox.idle_timeout controls how long released warm VMs stay running; 0
disables idle reaping. Active boxes are never evicted to satisfy the cap.
Status
Verified end-to-end against a live box (provider resolution → execute_command
→ file ops) on macOS/HVF. Linux/KVM validation and benchmarks vs. the AIO
sandbox are tracked in
#3936.