# ACP registry compact proof

Both sides: real web client, Chromium, 1280 x 800 CSS pixels, light theme, separate development servers and fresh isolated databases. No live database was copied. Provider: official registry entry pi-acp 0.0.34, executing its unmodified published adapter with the installed Pi runtime. The executable override launches that adapter; its Pi wrapper selects an available configured model and disables skills, extensions, and MCP. Model and environment labels are suppressed in the recordings for privacy. No conversation content or outcome was changed.

The replay scenario runner cannot establish provider-specific compaction behavior, so this uses a real provider.

1. Configure an ACP registry provider instance named compactProof, agentId pi-acp. Use the ordinary provider compaction retention settings.
2. Add an empty synthetic git workspace titled Compact context proof. Set its .pi/settings.json to {"quietStartup":true}.
3. Start a thread titled Registry compact command with this exact message: Remember these project facts: the release codename is Maple, the accent color is amber, and the launch day is Tuesday. Reply with one short sentence confirming the three facts. Do not use tools.
4. Run seed-proof.py CHECKOUT THREAD_ID on each side. It sends the same owner fact and the same deterministic 1,200-line synthetic checklist. Both turns must complete. This produces roughly 40,000 tokens of context; a tiny conversation is rejected by Pi as "Nothing to compact (session too small)".
5. Open the thread, hide the sidebar and thread details, and suppress only the model-selection button's metadata for privacy. Record the browser tab.
6. Type /compact in the composer without attachments, dismiss autocomplete with Escape, then click Submit message.
7. Base: the turn fails with "This provider does not support /compact. Start a new thread to continue with a fresh context." No successful compaction item is present.
8. Head: the provider replies "Compaction completed. Tokens before: 39854", provides its summary, and one Context compacted separator appears. Ask: What are the release codename, accent color, launch day, and release owner we agreed earlier? Reply in one sentence without tools.
9. Head replies with Maple, amber, Tuesday, and Jordan. Read-only inspection of this isolated thread confirms exactly one completed compaction item.

Each published still was checked against an identical second capture more than 500 ms later. Both recordings were inspected as frame contact sheets, including their first frames. No model identifiers, machine identifiers, credentials, or internal paths appear in the published captures.

Not verified: Compact context through the context-window meter. These Pi sessions exposed no context-window meter/action in either build, including after a follow-up turn and with thread details open. This proof establishes the attachment-free /compact path only.

AI-assisted; verified with the tests and tools listed above.