OpenCode 2 rejects the runtime ACP --cwd flag #236

OpenCode 2.1.3 rejects the routing runtime's ACP startup arguments before protocol initialization. This blocks the OpenCode Go qualification for release candidate #235 (runtime 5.0.10).

On the authorized Intel LabMacPro host, the official @opencode/cli@2.1.3 baseline binary reports opencode v2.1.3. Native metadata lists OpenCode Go as a stored API-key integration and exposes the Go model catalog. No credential values were inspected or copied.

A bounded native argument-parsing probe with closed stdin, zero ACP requests and zero prompts produced:

opencode acp --cwd /private/tmp
exit: 1
ERROR: Unrecognized flag: --cwd in command opencode acp

The current scripts/_agent_collab/native_carriers.py::_run_acp_carrier still appends --cwd although it already binds both the child process working directory and ACP session/new.cwd to the identity-checked execution directory. The prior test checked only argv[:2], so it missed the unsupported trailing arguments.

The narrow workspace repair removes that redundant flag, strengthens directory/model-selection/cleanup regressions and advances the runtime to 5.0.11. The signed candidate must be rebuilt and independently qualified before #235 can proceed. All previous failed qualification attempts remain preserved and unqualified. No V2 model request has been dispatched.

Official references: V2 ACP contract and 2.1.3 command declarations.