Summary

Once imsg coalesces Apple URL-preview split-sends upstream (openclaw/imsg#141), OpenClaw no longer needs to debounce + merge them client-side. At that point the entire client-side coalescing path — including the channels.imessage.coalesceSameSenderDms config — becomes dead weight and should be removed.

Background

Apple splits Dump https://example.com into a text row + a separate URL-preview row ~0.8–2s apart. Today OpenClaw handles this in the iMessage monitor:

• channels.imessage.coalesceSameSenderDms opts a DM into a 2.5s debounce window.
• Same-sender DMs bucket on chat:sender; on flush, the bucket merges if it carries imsg's balloon_bundle_id URL marker (fix(imessage): gate split-send coalescing on imsg metadata #90858), else falls back to a legacy merge (interim back-compat for older imsg builds).

This imposes up to 2.5s latency on every DM (you must hold the first row before the preview row can arrive) and duplicates logic that belongs in imsg.

What to remove (once imsg#141 ships and is the minimum supported build)

• channels.imessage.coalesceSameSenderDms config key (+ schema, help, defaults, docs).
• DM chat:sender bucketing, the 2.5s debounceMsOverride, and the shouldDebounce opt-in branch in extensions/imessage/src/monitor/monitor-provider.ts.
• combineIMessagePayloads / shouldCombineIMessagePayloadBucket + balloon helpers in extensions/imessage/src/monitor/coalesce.ts, including the interim back-compat branch added in fix(imessage): gate split-send coalescing on imsg metadata #90858.
• The balloon_bundle_id field plumbing in parse-notification.ts / types.ts if no longer consumed.
• Associated tests and docs.

Config-removal discipline (AGENTS.md)

coalesceSameSenderDms is persisted config. Per the runtime-reads-canonical-config rule, removing it requires an openclaw doctor --fix migration that drops the stale key from existing openclaw.json files — no runtime compat shim. This issue owns that migration.

Dependencies / sequencing

• Blocked on Coalesce Apple URL-preview split-sends into a single notification imsg#141 (upstream coalescing) merging and becoming the floor for supported imsg builds.
• fix(imessage): gate split-send coalescing on imsg metadata #90858 is the interim client-side implementation; this issue is its planned teardown.

Acceptance criteria

• coalesceSameSenderDms removed from the config surface; doctor --fix migrates existing configs.
• iMessage monitor no longer debounces DMs for split-send merging (no per-DM latency).
• URL split-sends still arrive as a single agent turn (now via imsg).
• Net non-test LOC decreases.