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ACP forwards internal compaction summary to clients as normal assistant output #50295
Description
Description
When auto-compaction runs, OpenCode creates an internal assistant message that stores the summary (summary: true). Over ACP, that message is forwarded to the connected client exactly like a normal reply: its text and reasoning are delivered as agent_message_chunk / agent_thought_chunk, both live through message.part.delta and again on session/load replay. Chat users end up seeing an unexplained wall of internal summary text.
The ACP event layer records part metadata without tracking the summary flag, so it cannot distinguish an internal summary message from a normal assistant reply.
This is not covered by #42316, which only filters compaction output from opencode run --format json (CLI JSONL). This report is about the ACP path.
Steps to reproduce
- Connect an ACP client to a session (for example a bridge that forwards ACP
session/updatenotifications to a chat). - Run a session until auto-compaction triggers.
- Observe the compaction summary content arriving as normal
agent_message_chunk/agent_thought_chunkupdates. - Reload the session (
session/load): the summary content is replayed again.
OpenCode version
2.0.11 (also present on current dev)
Operating System
Linux x64
Activity
nexxeln commentedon Oct 1, 2026
hey! this should be fixed in v2 now 🙏 if you're still on 1.x, upgrading to v2 should sort it out. let us know if you still hit it after upgrading and we'll take another look!
nexxeln commentedon Oct 6, 2026
Fixed on v2. Core streams compaction summaries as separate compaction events, not as assistant text, and the ACP agent sends a compaction marker (#52485) or ACP's compaction_update updates (#52737) instead of agent_message_chunk, both live and on session/load.
IsaacGao commentedon Oct 9, 2026
Thanks for the quick resolution and the pointers to #52485 / #52737 — much appreciated! 🙏