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Start with the symptom that best matches what you are seeing.
Confirm the container publishes -p 5500:5500 and that the client URL is exactly http://127.0.0.1:5500/mcp unless you changed the defaults.
Point health checks at http://127.0.0.1:5500/healthz. The attach sidecar is a separate service and is not the health endpoint.
Keep SYS_PTRACE, SYS_ADMIN, and unconfined seccomp and apparmor settings on the container.
Use container-visible paths such as /workspace/chal, and make sure the host file exists inside the mounted ./workspace directory.
Call set_file before run, or use attach when the process is already running.
Some helper families intentionally return JSON-formatted strings. See Response Shapes.
Confirm BINARY_URL is set and points to a URL the external RetDec service can fetch.

Fast checks

  1. Confirm Docker started successfully.
  2. Confirm your client points to the right transport.
  3. Confirm your binary exists under the mounted workspace directory.
  4. Confirm your tool calls use /workspace/... paths.
  5. Confirm you are using the correct session_id.

Preview this Mintlify site locally

npm --prefix docs run dev