DL-304

The notify-path snapshot comment set is keyed by a provider-stable string comment id (CommentRef.comment_key = 6; GitHub numeric id as string, Linear UUID) — NOT the comment URL, which the Linear COMMENT webhook payload cannot carry (it has only the parent issue URL, so a URL-keyed snapshot diverged between the webhook producer (issue URL) and the sweep producer (comment URL), a phantom-diff heartbeat). Both SnapshotComment and the digest drop the per-comment URL.

Status: Active (Matt, 2026-08-30)

Record: ../../server/compass-forge-agent-notification/design.md#global-constraints