[Perf][Pi] When messages accumulate, the transform becomes progressively slower and the TUI lags.

[FurryWolfX]

Short description

When messages accumulate, the transform becomes progressively slower and the TUI lags.

What happened?

When messages accumulate, the transform becomes progressively slower and the TUI lags.

Transform completed in 3337.1ms (5725 messages, 4194 targets, watermark: 4122.

Diagnostics

Plugin version

0.31.5

OpenCode version

No response

Platform

wsl

Client

Pi 0.80.3

Log output (optional)

[2026-07-10T01:36:16.193Z] [magic-context][019f496c-2bde-7a7d-a6ba-1846c7a18da6] transform completed in 3337.1ms (5725 messages, 4194 targets, watermark: 4122)

[ualtinok]

Thanks for the report — the timing line makes this easy to place. We can reproduce the slowdown and are actively working on it.

What's happening: the transform re-derives per-message bookkeeping on every pass, so its cost grows with total session length rather than with what actually changed. At your session's size (5725 messages) that reaches seconds per turn, and since it sits on the request path it lags the TUI.

We're building an isolated performance harness that replays real Pi sessions through the exact production transform and byte-compares outputs, so we can optimize the hot path aggressively (incremental tagging that only processes the new tail) while proving the output stays identical. Fix will land in an upcoming release; we'll update here when it ships.