The shared core applied `has_content_to_compress(head) is False -> nothing_to_do`
on every surface, where origin/main only had it in the gateway handler. That
predicate only knows the local summarizer's window: on CLI/TUI/ACP,
`_compress_context(force=True)` still routes codex_app_server sessions to native
compaction before any local-compressor check, and `ContextCompressor.compress`
commits the phase-1 tool-result prune / blank-echo drop even when no summary
window exists -- so the gate wrongly skipped real work there. It is now an opt-in
`skip_without_window` that only the gateway passes, restoring each surface's
prior behavior.
Review follow-up on #109610.
CLI, gateway, TUI and ACP each re-sequenced the same chain (partial split -> estimate ->
_compress_context(force=True) -> lock-skip detection -> rejoin tail -> summary), and the
flag set differed per surface: TUI treated `--preview` as a focus topic, ACP ignored
arguments entirely. For the one command that legitimately breaks the prompt cache that
divergence is a correctness problem, not a style one.
`agent/conversation_compression_manual.py::compress_now` owns the sequence; surfaces parse
their own argv, install `after_messages`, re-anchor session ids and render. TUI and ACP gain
`--preview`, `--aggressive` refusal and `here [N]` parity.
teknium1