agentHost: restrict Codex Copilot models to OpenAI - #333987
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Giuseppe Cianci (Giuspepe) merged 3 commits intoSep 2, 2026
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Third-party models can advertise the Responses endpoint without supporting the complete Codex request lifecycle. Keep picker and endpoint eligibility checks while limiting the Codex harness catalog to models whose vendor is OpenAI.
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Giuseppe Cianci (Giuspepe)
September 2, 2026 13:42
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Copilot review overview
🟡 Changes recommended
Two shared Codex test fixtures lack the now-required vendor and leave their model catalogs empty.
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Review tier: Balanced
Findings: 1
New issues introduced by this change (1)
| Severity | Finding |
|---|---|
 |
src/vs/platform/agentHost/node/codex/codexAgent.ts — This predicate is also exercised by the shared createAgent fixtures in… |
What changed in this PR
Restricts Codex’s Copilot-backed model catalog to OpenAI models while retaining existing eligibility checks.
Changes:
- Adds an OpenAI vendor filter.
- Adds regression coverage for excluded vendors.
- Updates relevant model-refresh fixtures.
| File | Description |
|---|---|
codexAgent.ts |
Filters Codex-compatible Copilot models by vendor. |
codexModelRefresh.test.ts |
Tests vendor filtering and updates fixtures. |
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The OpenAI-only model filter relies on the required vendor field. Keep the shared create-chat and prewarm fixtures valid so their gpt-test model remains available.
Giuseppe Cianci (Giuspepe)
marked this pull request as ready for review
September 2, 2026 14:54
Giuseppe Cianci (Giuspepe)
enabled auto-merge (squash)
September 2, 2026 14:54
Benjamin Christopher Simmonds (benibenj)
approved these changes
Sep 2, 2026
Giuseppe Cianci (Giuspepe)
deleted the
agents/debug-codex-harness-model-issues
branch
September 2, 2026 15:02
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Fixes #331354
Summary
Why
Some third-party models advertise the Responses endpoint but do not support the complete Codex request lifecycle. They can work in the Copilot harness yet fail after being selected in the Codex harness. This positive vendor filter keeps incompatible models out of Codex without changing the Copilot harness catalog.
Verification