fix(sse): preserve tools echo on response.completed lifecycle event (#8990) (#9003)

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/8990-preserve-tools-response-completed.md

@@ -0,0 +1 @@
+- **fix(sse):** `stripResponsesLifecycleEcho` no longer strips `tools` from the `response.completed` snapshot — that terminal event is what Codex CLI rebuilds its tool list from, so stripping it left the client with zero tools. `tools` is still stripped from `response.created`/`response.in_progress`, and `instructions` (the >100KB size lever) is still stripped from all three ([#8990](https://github.com/diegosouzapw/OmniRoute/pull/8990))

open-sse/utils/responsesStreamHelpers.ts

@@ -201,7 +201,10 @@ export function stripResponsesLifecycleEcho(parsed: unknown): boolean {
     delete r.instructions;
     changed = true;
   }
-  if ("tools" in r) {
+  // Preserve tools on the terminal snapshot: response.completed is what
+  // Codex CLI rebuilds its tool list from (#8990). Same special-case as
+  // backfillResponsesCompletedOutput. Still stripped on created/in_progress.
+  if (obj.type !== "response.completed" && "tools" in r) {
     delete r.tools;
     changed = true;
   }

tests/unit/stream-strip-responses-lifecycle-echo.test.ts

@@ -39,7 +39,10 @@ describe("stripResponsesLifecycleEcho", () => {
     assert.deepEqual(event.response, {});
   });
 
-  it("strips fields from response.completed (preserving usage)", () => {
+  it("strips instructions but PRESERVES tools on response.completed (#8990)", () => {
+    // response.completed is the terminal snapshot Codex CLI rebuilds its tool
+    // list from — stripping tools here left the client with zero tools. Same
+    // special-case precedent as backfillResponsesCompletedOutput.
     const event = {
       type: "response.completed",
       response: {
@@ -54,8 +57,10 @@ describe("stripResponsesLifecycleEcho", () => {
     const changed = stripResponsesLifecycleEcho(event);
 
     assert.equal(changed, true);
+    // instructions is still stripped (the >100KB size lever, not reported broken).
     assert.equal("instructions" in event.response, false);
-    assert.equal("tools" in event.response, false);
+    // tools MUST survive on the terminal snapshot.
+    assert.deepEqual(event.response.tools, [{ name: "bash" }]);
     // Usage must survive — downstream tracking depends on it.
     assert.deepEqual(event.response.usage, {
       input_tokens: 100,