Fabro carried its own Sandbox trait long after every implementation
became a thin layer over the sandbox driver: one production type
implemented it, a delegation macro forwarded it, and each consumer crate
kept hand-written fakes of its thirty methods for tests. The trait
existed to be mocked, and the mocks pinned behavior that no provider
had — canned walk listings that ignored the traversal root, opaque
provider paths, activation failures with no lifecycle behind them.
There is now one sandbox type. RunSandbox keeps fabro's semantics — path
resolution against the run's working directory, the Bash exec policy,
git setup and push, credential refresh — as inherent methods over the
driver's exec, filesystem, search, and git facets, and every consumer
takes Arc<RunSandbox>. The directory, grep, and walk types are the
driver's own, re-exported from fabro-sandbox. The exec policy reports
the provider's measured duration rather than its own clock.
Tests script a sandbox through fabro-sandbox's MockSandbox: a struct of
fields (seeded files, the result every command returns, the platform,
a runtime directory) that hands out a RunSandbox over the driver's
scripted doubles and reads back what the code did — commands, timeouts,
environment, term stops, writes, deletes, existence probes. The
hand-written fakes in fabro-agent, fabro-acp, fabro-hooks,
fabro-workflow, and fabro-server are gone; the one wrapper a git
integration test still needs sits at the driver level, hiding a path
from a real Host sandbox. The refresh-ahead loop takes the refresh as a
closure so its schedule is tested without a sandbox at all.
The driver pin moves to the testing-crate stack head, which gained the
double behavior these ports needed: retention caps on scripted output,
canned walks narrowed to the requested base, upload and download on the
memory filesystem, and recorders for deletes, existence probes, and
term stops. One test that modelled a provider handing back opaque object
paths from a walk is removed: the driver contract has no such thing.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
SandboxSpec::Local and run reconnect now build a DriverSandbox over the
sandbox-driver Host provider instead of fabro's own LocalSandbox, which
is deleted. fabro_sandbox::local_sandbox designates the working
directory (created when missing, never removed), creates the Host handle
in a per-process registry, and learns the platform up front. A local
sandbox reports no provider id: it is its directory, which the run
record already carries, so reconnect rebuilds the handle over that
directory rather than by id.
The credential filter for explicit environment variables and the Bash
readiness probe now come from the exec layer and the driver's activate
helper. Test call sites move to the async constructor; test factories
that must stay synchronous share the parent session's sandbox handle.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
