Problem

Since v2026.2.17, the Slack channel provider crashes immediately on startup with:

[default] channel exited: Cannot read properties of undefined (reading 'listeners')

The provider enters a 1/10 → 10/10 crash loop and never recovers. Slack is completely non-functional.

Root Cause

registerSlackMonitorSlashCommands → registerArgOptions() destructures ctx.app.options into a local variable:

const optionsHandler = (ctx.app as unknown as { options?: ... }).options;
//                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
//                      detached from `this` — classic JS footgun
optionsHandler(SLACK_COMMAND_ARG_ACTION_ID, ...);
//             `this` is `undefined` inside Bolt's App.options()

Bolt's App.options() pushes to this.listeners, but this is undefined because the method was called without its receiver.

Other Bolt methods in the same file (ctx.app.action(), ctx.app.command(), ctx.app.view()) are called directly on the app instance and work fine. Only options was destructured.

Fix

-    ).options;
+    ).options?.bind(ctx.app);

One-line fix. Preserves this binding. The optional chain (?.) keeps the existing guard for environments where options may not exist.

Stack Trace

TypeError: Cannot read properties of undefined (reading 'listeners')
    at options (App.ts:849:10)
    at registerArgOptions (subagent-registry-DN6TUJw4.js:48854:3)
    at registerSlackMonitorSlashCommands (subagent-registry-DN6TUJw4.js:48881:2)
    at monitorSlackProvider (subagent-registry-DN6TUJw4.js:49075:2)

Verification

Patched the bundled dist on a live 2026.2.17 instance. Before: crash loop. After: slack socket mode connected — full inbound/outbound working.

Affected Versions

• Broken: v2026.2.17
• Working: v2026.2.15

Fixes #19788
Ref: #8404

Greptile Summary

One-line fix for a critical crash-loop in the Slack channel provider introduced in v2026.2.17. The App.options() method from @slack/bolt was destructured into a local variable, detaching it from its this context. Since Bolt's App.options() internally accesses this.listeners, calling the detached method throws Cannot read properties of undefined (reading 'listeners'), crashing the provider on startup.

• Adds .bind(ctx.app) when extracting options from the Bolt app instance, preserving the method's this context
• The ?. optional chain is retained so environments where options doesn't exist continue to work via the existing typeof optionsHandler !== "function" guard
• Other Bolt methods (ctx.app.command(), ctx.app.action()) are called directly on the instance and were unaffected

Confidence Score: 5/5

• This PR is safe to merge — it is a minimal, well-understood one-line fix for a critical crash-loop regression.
• The fix is a single-line change that correctly addresses a classic JS this-binding issue. The root cause and solution are clear, the author verified it on a live instance, and the change has no side effects on surrounding code. No new logic or risk is introduced.
• No files require special attention.

_{Last reviewed commit: cf31361}

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