Summary

Discord tool-approval buttons are broken. When the agent posts an approval prompt and the user clicks any approve/deny button, Discord shows "This interaction failed" and the tool call is never acknowledged. This was reported by a user and is a confirmed NetClaw regression.

User-facing symptom

• Discord integration is otherwise working — the user can converse with the agent over Discord.
• When the agent requests approval for a tool use and the user clicks an approval button, Discord immediately shows "This interaction failed."
• The approval never reaches the session — the tool call stalls.

Logs (sanitized)

Promoted Discord session to thread reply_channel=<channel-id>
[WRN] Netclaw.Channels.Discord.Transport.DiscordNetGatewayClient: Failed to defer Discord button interaction <interaction-id>
System.TimeoutException: Cannot defer an interaction after 3 seconds of no response/acknowledgement
   at Discord.WebSocket.SocketMessageComponent.DeferAsync(Boolean ephemeral, RequestOptions options)
   at Netclaw.Channels.Discord.Transport.DiscordNetGatewayClient.OnButtonExecutedAsync(SocketMessageComponent component)

Diagnosis

Discord requires a button interaction to be acknowledged within 3 seconds of the click, or it is rejected with "This interaction failed".

In DiscordNetGatewayClient.OnButtonExecutedAsync (src/Netclaw.Channels.Discord/Transport/DiscordNetGatewayClient.cs:140), await component.DeferAsync() is already the first statement of the handler (line 144) — so the handler body is not the source of the delay. The 3-second window is being consumed before our handler runs, i.e. the Discord.NET gateway event loop appears to be congested/blocked, so the ButtonExecuted event is dispatched late and even an immediate DeferAsync() misses the deadline.

The log line immediately preceding the failure is notable:

Promoted Discord session to thread reply_channel=<channel-id>

emitted from DiscordSessionBindingActor.cs:1065. The session-promotion-to-thread path running on/around the gateway event dispatch is a strong candidate for what is stalling the loop.

A likely regression candidate worth bisecting first: #982 ("Button approvals route by SessionId"), which reworked the approval-button routing path. If the new routing does more synchronous work before the handler can defer (or changed how/when the handler is invoked relative to gateway dispatch), that would produce exactly this symptom.

Impact

Tool approvals over Discord are non-functional. Any workflow that requires the user to approve a tool call cannot proceed — this blocks the core approval/consent flow for Discord users.

Suggested investigation

• Confirm whether ButtonExecuted dispatch is being delayed by a blocked Discord.NET gateway task (Discord.NET runs event handlers on the gateway task by default; a slow handler stalls subsequent dispatch).
• Check whether the session-to-thread promotion (DiscordSessionBindingActor) or the post-fix(channels): route button approvals by SessionId so passivated gateways don't drop responses (#979) #982 approval routing performs blocking work on the gateway thread.
• Ensure the interaction is deferred immediately and independently of any actor/session resolution work — the ack must not wait on session promotion, ACL checks, or routing.
• Consider whether OnMessageReceivedAsync / other gateway handlers can hold up the loop long enough to eat the 3s budget for a concurrent button click.

Repro

1. Configure Discord integration.
2. Have the agent request a tool that needs approval.
3. Click any approval button on the prompt.
4. Observe "This interaction failed" in Discord and the TimeoutException in the daemon logs.

Environment

• Channel: Discord
• Component: Netclaw.Channels.Discord — DiscordNetGatewayClient.OnButtonExecutedAsync