Summary

createFollowupRunner unconditionally routes through runEmbeddedPiAgent, skipping the CLI-runtime dispatch branch the primary reply path uses. Any queued followup whose model resolves to a CLI runtime (claude-cli, codex-cli, google-gemini-cli) throws Requested agent harness "<runtime>" is not registered. and the queued message is silently dropped.

User-visible symptom: on bursty Signal threads (and any channel with queued followup delivery), only the most recent inbound that arrives while the agent is idle gets processed. Anything that lands mid-turn is queued, the drain crashes, and those messages vanish without surfacing an error.

Root cause

Throw site: selection-61FIEezO.js:9781-9799

const forced = pluginHarnesses.find((entry) => entry.id === runtime);
if (forced) return ...;
throw new Error(`Requested agent harness "${runtime}" is not registered.`);

Primary reply path (agent-runner.runtime-Dv_D_ax0.js:1030-1083) correctly checks for CLI runtimes first and routes them through runCliAgent:

const cliExecutionProvider = resolveCliRuntimeExecutionProvider(...) ?? provider;
if (isCliProvider(cliExecutionProvider, runtimeConfig)) {
  const result = await runCliAgent(...);
}

Followup queued runner (agent-runner.runtime-Dv_D_ax0.js:3034-3047) skips that branch entirely and always calls embedded Pi:

const fallbackResult = await runWithModelFallback({
  ...
  run: async (provider, model, runOptions) => {
    ...
    const result = await runEmbeddedPiAgent({ ... });

Embedded harness selection then looks up claude-cli (or codex-cli/google-gemini-cli) as a harness id — but those are registered as CLI backends by their plugins, not as runtime harnesses. Anthropic plugin registration:

• register.runtime-CR-c-hRh.js:403-405 → api.registerCliBackend(buildAnthropicCliBackend())
• Manifest extensions/anthropic/openclaw.plugin.json:54-56 → cliBackends entry, not a runtime harness

How to reproduce

1. Configure a session whose agents.defaults.models[<id>].agentRuntime.id is claude-cli (or codex-cli/google-gemini-cli).
2. Send a message that triggers a long-running turn (tools, subagents).
3. While that turn is in flight, send a second message on the same channel. It enters the followup queue.
4. When the primary turn completes, the followup drain runs → throws Requested agent harness "claude-cli" is not registered. → queued message is dropped.

Affects every queued lane that goes through createFollowupRunner: followup, collect, steer-backlog, cron/system-event followups.

Note: parent/child sharing the same runtime does not avoid the bug if that runtime is a CLI runtime. The dispatcher problem is independent of inheritance — it triggers whenever the queued lane resolves to any CLI runtime id.

Recommended fix (upstream)

In createFollowupRunner, before runEmbeddedPiAgent, perform the same CLI check the primary path does:

const cliExecutionProvider = resolveCliRuntimeExecutionProvider(...) ?? provider;
if (isCliProvider(cliExecutionProvider, runtimeConfig)) {
  return runCliAgent(...);  // with the queued run params
}
return runEmbeddedPiAgent(...);

Keeps claude-cli / codex-cli / google-gemini-cli as CLI backends instead of pretending they're harnesses.

Risk: affects all queued lanes — followup, collect, steer-backlog, cron/system-event followups, and any lane draining queued replies. Tests should cover:

• Signal followup delivery for CLI runtimes
• CLI session binding reuse across the drain
• Fallback to embedded Pi for non-CLI runtimes (regression check)
• Duplicate-delivery semantics through the CLI output bridge