Summary

After updating to OpenClaw 2026.4.22 (00bd2cf), the openclaw ACP harness still appears broken.

The ACP bridge starts and reports ready, but:

• openclaw acp client accepts input and then hangs without responding
• ACP one-shot runs via the embedded ACP runtime produce no output and time out after 120s
• stream logs contain only start, stall, and final timeout/error events, with no assistant/tool/output events at all

This suggests the failure happens after ACP startup, during turn processing / event emission, not during basic bridge boot.

Environment

• OpenClaw: 2026.4.22 (00bd2cf)
• OS: WSL2 / Linux
• Node: 22.22.2
• Gateway healthy and reachable
• ACP bundled runtime installed
• observed bundled dep log:
  • [email protected]

What works

openclaw acp --help

Works normally and prints help.

openclaw acp -v

Prints:

[acp] ready

and then remains idle.

openclaw acp client

Starts successfully, shows prompt, e.g.:

OpenClaw ACP client
Session: <session-id>
Type a prompt, or "exit" to quit.
>

So the ACP bridge/client shell itself appears to start correctly.

What fails

1. openclaw acp client never answers prompts

Example:

> Reply with exactly: pong

Observed behavior:

• prompt is accepted
• no response is ever produced
• same behavior for /debug

2. ACP one-shot run via OpenClaw runtime times out

Triggered with:

• agent: openclaw
• mode: one-shot ACP run
• prompt: Reply with exactly: pong

Observed result:

• child session is created
• no output is produced for 60s
• final timeout at 120s

Expected behavior

• openclaw acp client should answer simple prompts like Reply with exactly: pong
• ACP one-shot run should emit at least one output event and complete successfully

Actual behavior

• ACP startup succeeds to a “ready” state
• client prompt accepts input
• turn processing appears to hang indefinitely
• one-shot runtime runs time out with no first output

ACP runtime stream log

The run stream contained only:

{"kind":"system_event","text":"Started openclaw session ..."}
{"kind":"lifecycle","phase":"start"}
{"kind":"system_event","text":"openclaw has produced no output for 60s. It may be waiting for interactive input."}
{"kind":"lifecycle","phase":"error","data":{"error":"Timed out after 120000ms"}}
{"kind":"system_event","text":"openclaw run failed: Timed out after 120000ms"}

No assistant/tool/output/content events were emitted at all.

Gateway log signal

Gateway logs include:

acp startup identity reconcile (renderer=v1): checked=1 resolved=0 failed=1

I do not know whether this is causal, but it is one of the few ACP-related warnings visible near startup.

The final runtime error visible in logs is only the wrapper timeout, e.g.:

AcpRuntimeError: Timed out after 120000ms

No deeper cause is surfaced in the visible logs.

Reproduction steps

1. Start/update OpenClaw to 2026.4.22
2. Run:

   openclaw acp client

3. Enter:

   Reply with exactly: pong

4. Observe: no response is ever returned

Also reproducible through embedded ACP runtime:

1. Start ACP one-shot run with agent openclaw
2. Prompt:

   Reply with exactly: pong

3. Observe:
   • 60s stall
   • 120s timeout
   • no output events

Additional note

This does not look like a pure web UI issue, because the same hang reproduces in local terminal via openclaw acp client.