Sandbox.start() crashes with TypeError: APIError.__init__() missing 1 required positional argument: "message" when image is missing

[laohuan12138]

Description

Running deadend --target <url> fails immediately with:

Failed to instantiate agent: Failed to create sandbox: APIError.__init__() missing 1 required positional argument: 'message'

Root cause

Two layers:

1. Missing sandbox image — xoxruns/sandboxed_kali could not be pulled (Docker Hub unreachable in our environment). RPC server log (~/.cache/deadend/logs/rpc-server-*.log):

   Error pulling sandboxed Kali image: 500 Server Error ... "Get "https://registry-1.docker.io/v2/": context deadline exceeded"
   Image not found xoxruns/sandboxed_kali
   Failed to create sandbox: APIError.__init__() missing 1 required positional argument: 'message'
   

2. Bug masking the real error — in deadend_agent/src/deadend_agent/sandbox/sandbox.py, Sandbox.start() re-raises docker exceptions by constructing a new exception with no message:

   except ImageNotFound as exc:
       logger.error("Image not found %s", container_image)
       raise ImageNotFound from exc      # ImageNotFound() → APIError() → TypeError
   except NotFound as exc:
       logger.error("Docker error: %s", exc.explanation)
       raise NotFound from exc

   docker.errors.ImageNotFound / NotFound inherit APIError, whose __init__(self, message, response=None, explanation=None) requires message. Constructing ImageNotFound() with no args raises TypeError: APIError.__init__() missing 1 required positional argument: 'message', completely masking the real ImageNotFound and making the actual problem impossible to diagnose. Reproduced with docker SDK 7.1.0:

   >>> raise ImageNotFound from None
   TypeError: APIError.__init__() missing 1 required positional argument: 'message'

Expected behavior

Re-raise the original exception (raise exc) so callers see the actual docker.errors.ImageNotFound with its explanation.

Environment

• deadend CLI (OpenTUI rewrite, current main)
• docker SDK 7.1.0 (bundled)
• Linux (WSL2 / Kali)