[cdupuis]

codex-acp 2.5.0 declares @openai/codex ^0.165.0, so the adapter kit requires codex >= 0.165.0, < 0.166.0 and refuses the current codex and codex-mixin kits (0.166.0). Upstream has no release or open PR that moves the dependency; the pending 2.6.0 release (agentclientprotocol/codex-acp#708) still declares ^0.165.0.

This widens the requirement to < 0.167.0, moves codex-acp-set onto codex-mixin:0.166.0 and bumps the set to 1.0.7, and updates TestCodexACPExampleRequiresCompatibleCodex so 0.166.x is accepted and 0.167.0 is the first refused version.

Validation

Composed docker/sbx-kit-shell:1.0.0 + docker/sbx-kit-codex-mixin:0.166.0 + this branch's codex-acp in sbx on macOS arm64 with an OpenAI OAuth credential, and drove codex-acp over stdio. The same session ran against codex-mixin:0.165.0 + the published codex-acp:2.5.0 as the baseline.

• initialize, session/new (model list returned), and session/prompt streaming a reply to stopReason: end_turn behave the same on both, down to the token counts.
• Closing stdin immediately after the turn, 0.166.0 logs Failed to publish available commands ... app-server exited with code 0. The agent is shutting down. from a commands refresh still in flight. Waiting before closing stdin, both versions publish one available_commands_update and exit cleanly, so this is a shutdown race rather than an incompatibility.
• task validate and task test:unit pass.

Publishing

The published sbx-kit-codex-acp:2.5.0 still carries the old range, so the set cannot build against codex-mixin:0.166.0 until the adapter is republished. Order: codex-acp (2.5.0), then codex-acp-set (1.0.7).

Release note

The Codex ACP adapter kit now composes with Codex 0.166.

[Copilot]

🟢 Approval recommended

No active review issues were identified for the Codex 0.166 compatibility update.

No open issues 🎉

What changed in this PR

Updates the Codex ACP example kits to compose with Codex 0.166 while retaining compatibility with 0.165.

Changes:

• Widens the adapter’s Codex requirement to >= 0.165.0, < 0.167.0.
• Updates the composed set to use codex-mixin:0.166.0 and bumps its version to 1.0.7.
• Extends compatibility tests to accept 0.166.x and reject 0.167.0.

File	Description
examples/​codex-acp/​codex-acp.yaml	Widens the compatibility range and documents the validation requirement for future widening.
examples/​codex-acp-set/​codex-acp-set.yaml	Updates the Codex mixin reference and set version.
cmd/​frontend/​examples_set_test.go	Tests the revised compatibility boundaries.

_{Review effort: Balanced}