[oltolm]

Requirement or Bug

Related to #4158. Fix missing streamed text when repeated engine step numbers cause duplicate React keys.

Bug Reproduction Steps

See linked issue.

Root Cause

Engine step numbers restart for each core turn. Follow-up turns can therefore append steps with repeated numbers to the same assistant message without emitting another TurnBegin.

Using those numbers as React keys produced duplicate sibling keys and incorrect reconciliation, which could omit or leave stale streamed text until the view reloaded. Compaction steps could introduce the same collision.

This is a fundamental fix: React step identity no longer depends on engine numbering.

Code Changes

 ChatMessage
   StepContent
-    key={step.n}
+    key={globalIndex}

 ToolRenderers
   SubagentStep
-    key={step.n}
+    key={index}

Steps are append-only, so their array positions provide stable identities. Added regress for repeated step numbers in both main-message and subagent step lists.

Behavior Changes and Affected Users

Behavior	Before	After	Who relies on the old behavior	Escape hatch
VS Code chat rendering when engine step numbers repeat	Duplicate React keys could omit or leave stale text during streaming	Every appended main or subagent step retains a distinct React identity	None; duplicate keys were invalid React usage	N/A

Affected modules and coverage:

• ChatMessage.tsx: regression renders two main steps with the same engine number and verifies that both remain visible without duplicate-key errors.
• ToolRenderers.tsx: regression expands a subagent tool with repeated step numbers and verifies both steps.
• Both regressions fail with the old keys and pass with this change.
• pnpm --dir apps/vscode run typecheck: passed.
• pnpm --dir apps/vscode run build: passed.
• pnpm lint: passed.
• Full VS Code suite: 382 tests passed; three failures remain in UNC-path,-tag, and replay-display tests outside this diff.

Checklist

• I have read the CONTRIBUTING document.
• I have linked a related issue (external PRs: issue must have a maintainer's /approve).
• I have added tests that prove my feature works.
• The behavior-change table above is complete, and every removed behavior or flipped default is named in the changeset and either has an escape hatch or was explicitly approved by a maintainer in this PR.
• Ran gen-changesets skill, or this PR needs no changeset.
• Ran gen-docs skill, or this PR needs no doc update.

[changeset-bot]

🦋 Changeset detected

Latest commit: 2429899

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
kimi-code	Patch

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[chatgpt-codex-connector]

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Review	Status	Commit	Review trigger
📝 Code Review	⚠️ Failed 2026-10-25T10:29:34.389951Z We couldn’t complete this review. Comment @codex review to try again.	c87dee3	PR opened

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