In Docker production deployments, LocalSandboxProvider runs inside the
deer-flow-gateway container, so any `sandbox.mounts[].host_path` from
config.yaml is resolved against the gateway container's filesystem — not
the host machine. When the path isn't also bind-mounted into the gateway
service, the mount was silently dropped with only a WARNING log, leaving
agents reading an empty directory in production while the same config
worked under `make dev`.
Escalate the missing-host_path branch to logger.error with explicit
guidance about Docker bind mounts and docker-compose, so the failure is
hard to miss in default log configurations. Skip behaviour is preserved
to avoid breaking existing deployments.
Also clarify the misleading `VolumeMountConfig.host_path` field
description so it documents reality for both providers:
- LocalSandboxProvider checks host_path from inside the gateway process
(host in `make dev`, container in `make up`).
- AioSandboxProvider (DooD) passes host_path straight to `docker -v`
for the sandbox container, where the host Docker daemon resolves it
from the host machine's perspective.
config.example.yaml's `sandbox.mounts` comment gets a Note: block
pointing operators at the docker-compose bind-mount requirement so the
Docker-mode gotcha is discoverable from the canonical template.
Adds a regression test that:
- confirms missing host_path is still skipped (no behaviour break);
- asserts an ERROR record is emitted referencing the offending paths;
- asserts the message contains actionable Docker/gateway/docker-compose
keywords so future refactors can't quietly downgrade it.
Refs: https://github.com/bytedance/deer-flow/issues/3244
ae9e8bc0bf