OpenClaw Persistent Sub-Agent Sessions Broken: mode="session" + thread=true Circular Dependency

If your orchestrator agent can't spawn persistent sub-agent sessions — the spawning call hangs, returns an error, or the sub-agent never initializes — you've likely hit issue #67400. Combining mode="session" and thread=true creates a circular dependency that prevents the session from being created. Here's the workaround.

What's Broken

In OpenClaw's sessions_spawn tool, using both mode="session" (persistent session) and thread=true (bind to a channel thread) together triggers a circular dependency in the session resolution logic. The session can't initialize because each parameter depends on the other being resolved first.

Symptoms:

• Sub-agent spawn call hangs or times out
• Error in logs: session initialization failure or circular dependency reference
• The sub-agent appears briefly then disappears without completing initialization
• Orchestrator agent receives no session key back from the spawn call

Who's Affected

This primarily hits users building multi-agent Discord or Slack setups where the orchestrator spawns specialized sub-agents as persistent, thread-bound sessions. It's a common pattern for teams running agent orgs that report back in dedicated threads — exactly the architecture OpenClaw's ACP harness is designed for.

Workaround #1 — Use mode="run" Instead of mode="session"

If the sub-agent doesn't need to maintain persistent state across multiple calls, switch to mode="run":

// Broken
sessions_spawn({
  task: "...",
  mode: "session",
  thread: true,
  runtime: "acp"
})

// Workaround
sessions_spawn({
  task: "...",
  mode: "run",   // one-shot instead of persistent
  thread: true,
  runtime: "acp"
})

Trade-off: mode="run" sessions don't persist history. If your sub-agent needs to remember context across calls, this workaround loses that.

Workaround #2 — Create the Thread First, Then Spawn Without thread=true

Pre-create the thread manually, then spawn the sub-agent targeting that thread's channel ID — without passing thread=true:

// Step 1: Create thread via message tool
message({
  action: "thread-create",
  channel: "discord",
  channelId: "YOUR_CHANNEL_ID",
  threadName: "Agent Task Thread"
})
// Returns: threadId

// Step 2: Spawn sub-agent targeting the thread channel directly
sessions_spawn({
  task: "...",
  mode: "session",
  runtime: "acp",
  // pass channel context in task description instead of thread=true
})

This splits the two concerns — thread creation and session persistence — into separate steps, avoiding the circular dependency.

Workaround #3 — Pin to 4.12 for Critical Multi-Agent Setups

If persistent thread-bound sub-agent sessions are core to your setup and neither workaround above works for your use case:

npm install -g openclaw@2026.4.12
openclaw gateway restart

4.12 predates the regression that introduced this circular dependency.

Status

Issue #67400 is open and marked as a regression. It's on the radar for the 4.15 stable release. Watch the issue for updates — this is a common enough pattern that it should get prioritized.

TL;DR

• mode="session" + thread=true = circular dependency = sub-agent spawn fails
• Workaround A: use mode="run" if persistence isn't required
• Workaround B: pre-create the thread, then spawn without thread=true
• Workaround C: pin to 4.12 for critical setups
• Tracking: GitHub issue #67400