description

macOS CI runner consistently fails with a TypeError in the Slack auth test suite. this doesn't reproduce on Linux or Windows runners — only macOS.

error

TypeError: Cannot read properties of undefined (reading 'catch')
 ❯ resolveSlackEffectiveAllowFrom src/slack/monitor/auth.ts:6:65
 ❯ prepareSlackMessage src/slack/monitor/message-handler/prepare.ts:129:36
 ❯ prepareWithDefaultCtx src/slack/monitor/message-handler/prepare.test.ts:107:12

multiple test cases in prepare.test.ts hit this (lines 363, 377, and others).

impact

this is currently causing macOS CI failures on unrelated PRs. every PR that triggers the macOS job gets a red X from this, even though it has nothing to do with their changes.

examples:

• fix: validate tool access against Docker bind mounts #19055 (Docker bind mount validation)
• fix: enable auth rate limiting by default #16963 (auth rate limiting default)

likely cause

resolveSlackEffectiveAllowFrom in src/slack/monitor/auth.ts line 6 calls .catch() on something that's undefined in the macOS test environment. probably a missing mock or a platform-specific dependency that doesn't resolve the same way on macOS runners.