feat: /close command to manually terminate a thread session

[qijie850]

Problem

Currently the only way to free a session slot is to wait for TTL expiry or restart agent-broker. Users have no way to manually end a session when they're done with a thread.

This becomes important when session_ttl_hours is set high (e.g. 7 days) to preserve context — sessions accumulate and can hit max_sessions.

Proposed Solution

Add a /close (and /end alias) command that users can type inside a thread to:

1. Kill the ACP child process (free RAM)
2. Remove the session mapping (if session persistence is implemented, ref feat: per-thread isolated working directories #38)
3. Clean up the working directory (if per-thread dirs are implemented, ref feat: per-thread isolated working directories #38)
4. Reply with confirmation in the thread

Implementation

In discord.rs, intercept the command before passing to the ACP agent:

// In message handler, before get_or_create:
if prompt.trim().eq_ignore_ascii_case("/close") || prompt.trim().eq_ignore_ascii_case("/end") {
    if in_thread {
        let thread_key = msg.channel_id.get().to_string();
        pool.close_session(&thread_key).await?;
        msg.channel_id.say(&ctx.http, "✅ Session closed.").await?;
    }
    return;
}

In pool.rs, add a close_session method:

pub async fn close_session(&self, thread_id: &str) -> Result<()> {
    let mut conns = self.connections.write().await;
    if conns.remove(thread_id).is_some() {
        info!(thread_id, "closed active session");
    }
    // Optionally clean up working directory and persisted mapping
    Ok(())
}

Additional Considerations

• Could also support /status to show active session count / current thread info
• The command should only work inside threads (not in the main channel)
• Related: feat: per-thread isolated working directories #38 (per-thread working directories — cleanup on close)

We've tested this locally and it works well. Happy to submit a PR.

[thepagent]

Good complement to #38. The basic session kill (steps 1 & 4) can land independently, but full cleanup (steps 2 & 3 — removing session mapping and working directory) depends on #38 being merged first.

Suggested approach:

• Base your PR on feat: per-thread isolated working directories #38's branch so both can be reviewed together
• Or split into two PRs: basic /close first, then cleanup after feat: per-thread isolated working directories #38 merges

/status would be a nice follow-up too.

Looking forward to the PR!

[thepagent]

One concern: if the agent itself has a /close command (e.g. Claude Code slash commands), text-based interception in the broker would shadow it — users could never reach the agent's /close.

Recommend using Discord slash commands instead of text matching:

Text message "/close"  ──> forwarded to ACP agent (agent's command)
Slash command /close   ──> handled by broker (Discord interaction event)

Discord slash commands are a different event type (InteractionCreate vs MessageCreate), so there's zero collision. The broker registers /close as a slash command, and text messages starting with / pass through to the agent untouched.

This also gives you autocomplete, parameter validation, and a cleaner UX for free.

[qijie850]

Great call on using Discord slash commands instead of text matching — totally agree about the shadowing risk.

PR submitted: #42. Uses InteractionCreate with a globally registered /close command. Text messages with /close pass through to the agent untouched.

Based on the #38 branch as you suggested.

[chaodu-agent]

The implementation looks clean and we like the direction. To help prioritize, could you flesh out the use case a bit?

1. How many concurrent users are you running with? How quickly do you hit max_sessions?
2. What's your session_ttl_hours set to? And how often do users actually need sessions to stay alive that long?
3. Is the main pain point pool exhaustion, or just wanting a clean way to end a conversation?

This will help us decide if /close should land as a standalone fix or as part of the broader session management work (#75).