[codex] Honor disabled compression for reactive compaction (#9200)

Validated in local merge-train (devbox-vm-06-dev002) @ combined-tip (FAST gates green: static + changed tests + vitest — only pre-existing audit.test.ts flake). Evidence: /home/diegosouzapw/dev/proxys/OmniRoute/.claude/worktrees/merge-train-20260805-213228-suite.log

changelog.d/fixes/9200-compression-off-reactive-compaction.md

@@ -0,0 +1 @@
+- **fix(compression):** honor the global compression-off setting for proactive and last-resort context compaction, preventing disabled compression from rewriting tool-call histories ([#9200](https://github.com/diegosouzapw/OmniRoute/pull/9200)) — thanks @joachimBrindeau

open-sse/handlers/chatCore.ts

@@ -1092,6 +1092,10 @@ export async function handleChatCore({
   // settings read below, then threaded to executor.execute() further down. Lives at
   // function scope because the read happens inside the per-message compression block.
   let contextEditingEnabled = false;
+  // The dashboard's global compression switch must also control the built-in
+  // reactive and last-resort compaction passes. Otherwise an operator selecting
+  // "off" still has large histories rewritten by trim_tools/purify_history.
+  let reactiveContextCompactionEnabled = false;
   // Hoisted to function scope (not just the compression-block scope below) so the
   // combo-resolved override survives to the final enforceOutputTokenBudget() call
   // further down — see #8378 (context limit resolved by the combo was silently
@@ -1108,6 +1112,7 @@ export async function handleChatCore({
       compressionSettings?.exclusions
     );
     let promptCompressionEnabled = compressionSettingsResult.enabled && !compressionExcluded;
+    reactiveContextCompactionEnabled = compressionSettingsResult.enabled && !compressionExcluded;
     contextEditingEnabled = compressionSettingsResult.contextEditingEnabled;
     if (compressionExcluded) {
       void writeCompressionSkip(
@@ -1757,7 +1762,7 @@ export async function handleChatCore({
     // engines (Caveman/RTK). Codex Desktop / Responses clients need this path even
     // when those engines are off, otherwise multi-turn image sessions hard-reject
     // at the budget check below (#8560).
-    if (estimatedTokens > threshold) {
+    if (reactiveContextCompactionEnabled && estimatedTokens > threshold) {
       log?.info?.(
         "CONTEXT",
         `Proactive compression triggered: ${estimatedTokens} tokens > ${threshold} threshold (${contextLimit} limit)`
@@ -1848,7 +1853,7 @@ export async function handleChatCore({
 
   // Last-resort compaction against the concrete input budget (not the 70% threshold).
   // Covers cases where the proactive pass was skipped or still left the request oversized (#8560).
-  if (finalEstimatedInputTokens >= finalContextLimit && body) {
+  if (reactiveContextCompactionEnabled && finalEstimatedInputTokens >= finalContextLimit && body) {
     const lastResortTarget = Math.max(1, finalContextLimit - toolsReserve - 1);
     const lastResortAdapter = adaptBodyForCompression(body as Record<string, unknown>);
     const lastResortResult = compressContext(lastResortAdapter.body, {

tests/unit/reactive-context-compaction-policy.test.mjs

@@ -0,0 +1,20 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+import { readFileSync } from "node:fs";
+
+const source = readFileSync(
+  new URL("../../open-sse/handlers/chatCore.ts", import.meta.url),
+  "utf8"
+);
+
+test("global compression off gates reactive and last-resort context compaction", () => {
+  assert.match(
+    source,
+    /reactiveContextCompactionEnabled\s*=\s*compressionSettingsResult\.enabled\s*&&\s*!compressionExcluded;/
+  );
+  assert.match(source, /reactiveContextCompactionEnabled\s*&&\s*estimatedTokens\s*>\s*threshold/);
+  assert.match(
+    source,
+    /reactiveContextCompactionEnabled\s*&&\s*finalEstimatedInputTokens\s*>=\s*finalContextLimit/
+  );
+});