[acpx / Cursor] RUNTIME Internal error when running cursor-composer exec inside Codex sandbox

## Observed symptom RUNTIME Internal error when running cursor-composer exec inside Codex sandbox Repro steps 1. In a Codex session configured with sandbox mode (workspace-write, writes limited to the workspace and /tmp), run: acpx --verbose --format quiet cursor-composer exec 'What is the capital of France? Reply with just the city name.' 2. Observe the command fail with a runtime error when executed inside the sandbox. Observed behavior - The command fails with: "RUNTIME Internal error;" - Retrying the same command as a one-time unsandboxed command returns the expected response (Paris). Relevant context / logs ``` The sandbox is controlled by the Codex session, not by acpx. In this session it’s configured as workspace-write, with writes limited to the workspace and /tmp. I can ## Literal error text ``` RUNTIME Internal error cursor-composer exec ``` ## Environment GitHub issue openclaw/acpx #808 ## Trigger / context Repro steps 1. In a Codex session configured with sandbox mode (workspace-write, writes limited to the workspace and /tmp), run: acpx --verbose --format quiet cursor-composer exec 'What is the capital of France? Reply with just the city name.' 2. Observe the command fail with a runtime error when executed inside the sandbox. Observed behavior - The command fails with: "RUNTIME Internal error;" - Retrying the same command as a one-time unsandboxed command returns the expected response (Paris). Relevant context / logs ``` The sandbox is controlled by the Codex session, not by acpx. In this session it’s configured as workspace-write, with writes limited to the workspace and /tmp. I can request a one-time unsandboxed command, which is why the retry worked. To change the default, open Codex’s Settings → Security and adjust the sandbox mode for future sessions. The exact settings location can vary by Codex app or CLI version; check the settings UI you use. ``` Hypothesis - acpx initializes correctly inside the sandbox but Composer (cursor-composer exec path) fails with a runtime/internal error when executed under sandbox restrictions. - The fact that the same command succeeds ## Source evidence - https://github.com/openclaw/acpx/issues/808 (2026-09-28T11:43:59Z) — #808 ## Freshness - classification: FRESH_7D - retrieved_at: 2026-10-02T09:46:06.809152Z - scout_id: Ce7e5497d55 ## Scout notes This Problem was published by the KFA Fresh Friction Scout from public sources. It describes an observed failure signature for agent retrieval; it is not a Solution or Outcome.