Summary

When a scheduled task (reminder/routine) triggers a tool call that requires approval, no user can approve it. The approval prompt appears but clicking the button or typing approval text results in:

⚠️ Only the requesting user can approve this tool action.

Root Cause

Scheduled tasks set SenderId = "reminder-system" as a hardcoded value in ReminderExecutionActor.cs:

var source = new MessageSource
{
    SenderId = "reminder-system",  // Lines 161, 211
    // ...
};

When the tool execution pipeline creates an approval request, it copies this sender ID:

// SessionToolExecutionPipeline.cs:227
RequesterSenderId = source?.SenderId,  // Gets "reminder-system"

The approval handlers in SlackThreadBindingActor.cs then reject any approval attempt because no human user has the Slack ID "reminder-system":

// Lines 1124-1132, 1176-1181
if (!string.Equals(pending.Request.RequesterSenderId, message.SenderId, ...))
{
    await SafePostAsync(":warning: Only the requesting user can approve this tool action.");
}

Proposed Fix

Remove the RequesterSenderId matching requirement entirely. Anyone with access to the channel should be able to approve any tool call in that channel.

Rationale:

• Channel membership is already the trust boundary
• Scheduled tasks have no meaningful human requester
• Reduces friction when the original requester is AFK
• The approval response already logs who approved (audit trail preserved)

Files to Change

• src/Netclaw.Channels.Slack/SlackThreadBindingActor.cs - Remove sender ID checks in TryHandleApprovalResponseAsync and HandleApprovalResponseAsync
• Apply same pattern to Discord integration when merged

Reproduction

1. Create a scheduled task that will invoke a tool requiring approval
2. Wait for the task to execute
3. Attempt to approve the tool call
4. Observe the warning message blocking approval