Module shell 

Shell execution backend abstraction.

ShellBackend is the trait boundary between the bash tool and the underlying process management. Two implementations:

• defect_tools::shell::LocalShellBackend: spawns child processes directly
• defect_acp::shell::AcpShellBackend: delegates to the client via ACP terminal/* reverse requests

Assembly is handled in the defect-acp session/new handler — it selects the backend based on the client’s ClientCapabilities::terminal negotiation result and injects it into crate::session::AgentCore::create_session.

Structs

NoopShellBackend

A no-op shell backend for testing only. All methods return ShellError::NotPermitted, allowing test scenarios that require an Arc<dyn ShellBackend> (without actually running a shell tool) to skip setup.

ShellOutput

A snapshot result of ShellBackend::output.

TerminalExitStatus

Exit status of a terminal process.

TerminalId

A terminal handle. Internally, in the backend, it maps to a PID + monotonic counter (local) or an ACP schema’s TerminalId (acp).

Enums

ShellError

Errors from the shell backend.

Traits

ShellBackend

Shell backend trait.