Review follow-up on the salvaged #89444:
- Warn fires only from the conversation-loop pre-API site, reusing the
unconditionally computed request_pressure_tokens (zero marginal cost,
covers turn-start AND mid-turn growth) — drops the duplicate every-turn
estimate the turn-context block paid.
- Turn-context block now only RE-ARMS the dedup once the session is back
under the window, so warn -> /compress -> regrow warns again (the dedup
was previously never cleared with compression disabled).
- Char pre-check treats non-string (multimodal) content as over-gate —
len() of a part list defeated the 20k char floor (probe: 10 'chars' vs
~70k real tokens) — and compares against the window, not a flat 20k.
- Deletes the unreachable get_model_context_length fallback from both
sites (context_compressor always exists; its context_length property
hard-floors positive; the fallback would have been a synchronous
network probe mid-turn that also bypassed config overrides) and the
undeduped inline _emit_warning fallback (third copy of the message).
- Tests bind the PRODUCTION warn/clear methods (previously a verbatim
fake reimplementation left them uncovered) and add dedup, re-arm,
no-rearm-while-over, and multimodal-gate coverage.
When compression is explicitly disabled (compression.enabled: false), conversations can grow past the model's context window across hundreds of messages (e.g., 824 messages / 460K+ tokens in #89297). Serializing massive JSON payloads repeatedly under memory-constrained environments leads to swap thrashing (STAT=U) and unhandled provider errors.
Add a pre-flight uncompressed context overflow guardrail in build_turn_context and a deduped _warn_uncompressed_context_overflow method on AIAgent to alert users to run /compact or enable compression before unmanageable payloads freeze the process.
kshitijk4poor