Summary

Tool results (exec stdout/stderr, JSON dumps, command output) are delivered as individual Slack messages in channels even when config fully disables verbose/block streaming. Root cause: the shouldSendToolSummaries gate only treats ChatType === "group" as multi-user, but Slack channels arrive as ChatType === "channel".

Environment

• OpenClaw (npm global install at /opt/homebrew/lib/node_modules/openclaw)
• Channel: Slack (chat_type: "channel" per inbound meta)
• macOS 25.4.0 arm64, node v25.6.1

Config (verified correct)

{
  "agents": {
    "defaults": {
      "verboseDefault": "off",
      "blockStreamingBreak": "message_end"
    }
  },
  "channels": {
    "slack": {
      "streaming": { "block": { "enabled": false } }
    }
  }
}

Observed

In a Slack channel (not DM, not group DM), each tool call posts its output as its own Slack message:

[16:42] Creating it now.                              ← assistant block reply
[16:42] Expecting value: line 1 column 1 (char 0)     ← tool stderr
[16:42] (Command exited with code 1)                  ← exec wrapper
[16:42] {... full conversations.create JSON ...}       ← tool stdout
[16:42] existing slack channels: [...]                 ← tool stdout

Block-reply streaming is already correctly disabled — that path works. The leak is on the tool-result path.

Root cause

dist/dispatch-JNo_iJw5.js:486:

const shouldSendToolSummaries = ctx.ChatType !== "group" || ctx.IsForum === true;

Slack channels set ctx.ChatType === "channel", so the expression evaluates true → resolveToolDeliveryPayload returns the raw payload → dispatcher.sendToolResult posts it to Slack. The same gate correctly suppresses for WhatsApp groups etc. (where ChatType === "group").

Proposed fix

Treat any multi-user context as suppressing tool summaries by default:

const shouldSendToolSummaries = (ctx.ChatType !== "group" && ctx.ChatType !== "channel") || ctx.IsForum === true;

Or more robustly, drive off an isMultiUser flag so new surfaces don't need the list extending.

Workaround

Patch the bundled dispatch-JNo_iJw5.js line 486 locally (script attached downstream). Idempotent re-apply needed after each OpenClaw update.

Impact

In shared Slack channels the assistant spams the channel with raw tool output — command failures, large JSON blobs, etc. — making it unusable for group work and risking leaking sensitive tool output to other channel members despite explicit config to suppress.