sandbox exec rejects multi-line scripts passed to bash -c / python3 -c #1963

Agent Diagnostic

• Loaded openshell-cli skill, traced the exec validation pipeline
• Found reject_control_chars() in crates/openshell-server/src/grpc/validation.rs:72-84 blanket-rejects \n and \r in ALL command arguments
• Found shell_escape() in crates/openshell-server/src/grpc/sandbox.rs:1456-1474 independently rejects newlines during command construction
• No special handling exists for bash -c, sh -c, or python3 -c patterns where the argument IS a script
• Confirmed the rejection is at the gRPC validation layer, so it affects all callers (CLI, Python SDK, direct gRPC)

Description

sandbox exec rejects any command argument containing a newline (\n) or carriage return (\r). This blocks multi-line scripts passed to bash -c or python3 -c, which is the natural way agents produce executable code.

What happens:

Error: × code: 'Client specified an invalid argument', message: "command argument 2
  │ contains newline or carriage return characters"

What I expected: The script body passed to bash -c "..." should be accepted, since the user explicitly opted into shell interpretation.

Reproduction Steps

# 1. Create a sandbox
openshell sandbox create --name exec-newline-test

# 2. Try a multi-line python script (fails)
openshell sandbox exec -n exec-newline-test -- python3 -c "
def hello():
    print('hi')
hello()
"

# 3. Single-line equivalent works fine
openshell sandbox exec -n exec-newline-test -- python3 -c "print('hi')"

The same rejection happens via the Python SDK:

sandbox.exec(command=["bash", "-c", "echo 'line1\nline2'"])

Use case

We use sandbox exec to dispatch tasks from a lead AI agent via MCP. The agent sends multi-line scripts (Python, shell) as its natural output. Having to convert everything to single-line with semicolons is fragile and limits what agents can do.

Environment

• OpenShell: v0.0.66
• OS: macOS (Darwin 25.0.0, Apple Silicon)
• Compute driver: Podman (rootless, podman-machine)

Logs

Error: × code: 'Client specified an invalid argument', message: "command argument 2
  │ contains newline or carriage return characters"