ACPX Local (retired)
This adapter has been retired.
acpx_localis no longer a choice when you create an agent. ACP is now a capability of each harness adapter rather than a separate adapter, so pick the adapter that matches your harness and let ACP handle itself:
What replaced it
ACPX used to be the one adapter that could target Claude, Codex, or a custom ACP server. That turned ACP into a separate agent choice, when really it is an execution capability of the harness you already picked.
Now claude_local, codex_local, and gemini_local each speak ACP natively. Leave engine on its default auto and you get ACP whenever the host can support it, with an automatic fallback to the CLI lane when it cannot. Set engine: "acp" if ACP is required and a missing prerequisite should stop the run outright.
Each of those pages documents the ACP fields — agentCommand, mode, nonInteractivePermissions, stateDir, warmHandleIdleMs — in its own configuration section.
Runs natively on Windows
Good news if you work on Windows: your local ACP agents now run there too, right alongside Linux. The embedded ACPX engine used to launch each local agent command by wrapping it in a generated Bash script, which meant it only worked where a Bash shell was available. That wrapper is gone. Claude, Codex, Gemini, and any custom ACP adapter now spawn as a native process on whichever platform you're on — no shell script in the middle.
You don't need to change anything to get this. Set engine to auto (the default) or acp, pick the adapter that matches your harness, and the run starts the same way on Windows as it does on Linux.
Here's what changed under the hood so the native path behaves cleanly:
- Environment variables travel through ACPX session options. Instead of being baked into a shell script, your agent's environment (including the values Paperclip injects for a run) is handed to the ACPX runtime as part of the session options and applied when the process spawns.
- Agent output on stderr is captured in-process. The engine reads the child process's stderr directly rather than relying on shell redirection, so diagnostics still show up in your run log on every platform.
.cmdshims are preferred on Windows. When the engine resolves a bundlednpm/pnpmbinary fromnode_modules/.bin, on Windows it looks for the.cmdshim first (for examplepnpm.cmd) before falling back to the bare name — which is how these tools are actually installed on Windows.- Symlinks fall back to copies. Paperclip stages runtime skills and config files into place with symlinks. On Windows, creating a symlink can fail with an
EPERMpermission error; when that happens, the engine copies the file instead so setup still succeeds.
If you had an ACPX agent
You do not need to do anything. Existing acpx_local agents were migrated for you when your instance upgraded. The migration reads each agent's old agent field and moves it to the matching adapter:
Old adapterConfig.agent |
New adapter | New config |
|---|---|---|
codex |
codex_local |
engine: "acp" |
| anything else (including unset) | claude_local |
engine: "acp" |
For Codex agents, the old effort, reasoningEffort, and thinkingEffort fields are consolidated onto a single modelReasoningEffort value.
If you still see acpx_local in an error
Paperclip deliberately keeps the retired adapter registered so that a stale row fails with a clear message instead of silently falling back to the process adapter. If a run logs a retirement message naming acpx_local, that agent's row predates the migration — open the agent and switch it to claude_local or codex_local with engine set to acp.
Related
- Claude Code — Claude harness, ACP by default.
- Codex — Codex harness, ACP by default.
- Gemini CLI — Gemini harness, ACP by default.
- Adapters Overview — the full list of adapters you can pick today.
- Creating An Adapter — author your own when none of the built-ins fit.