[CLI 0.147.0 regression] gpt-5.6-sol sends tools: [] with a custom Responses provider

What version of Codex CLI is running?

codex-cli 0.147.0 installed from npm.

This is a regression from 0.146.1.

What subscription do you have?

Pro.

Which model were you using?

gpt-5.6-sol

What platform is your computer?

Microsoft Windows NT 10.0.22631.0 x64 (Windows 11 Enterprise)

What terminal emulator and version are you using?

Windows Terminal with PowerShell 7.6.3, Node.js 24.14.0, npm 11.6.1.

Codex doctor report

Not available from the failing installation because the machine was downgraded to 0.146.1 after confirming the regression. codex doctor --json on 0.146.1 reports that the npm installation, configuration, MCP configuration, and provider reachability are valid.

What issue are you seeing?

With npm Codex CLI 0.147.0, selecting gpt-5.6-sol through a custom Responses provider causes Codex to serialize requests with an empty tool list:

"tools": []

Consequently, the model cannot invoke the shell, MCP tools, or goal tools such as update_goal. In /goal mode this can produce an automatic continuation loop because the model cannot perform work and cannot mark the goal blocked.

This is not caused by the proxy stripping tools. Codex's own codex_http_client::transport trace shows that the serialized request already contains tools: [] before it is sent to the local provider.

The same configuration and provider behave as follows:

| Codex binary | Result |
|---|---|
| npm 0.146.1 | Shell tool call succeeds |
| npm 0.147.0 | No tool call; request contains tools: [] |
| Codex Desktop bundled 0.147.0-alpha.6.5 | Shell tool call succeeds |

Affected thread ID: 019fdb0c-5ed7-76c0-bafc-2d38914d1338.

What steps can reproduce the bug?

1. Model configure.

model = "gpt-5.6-sol"

1. Set an unpredictable value in the Codex process environment:

$env:CODEX_TOOL_PROBE_SECRET = "CODEX_TOOL_PROBE_$([guid]::NewGuid().ToString('N'))"

1. Run:

codex exec --ephemeral --skip-git-repo-check -s read-only -m gpt-5.6-sol 'Use the shell tool to run this PowerShell command: Write-Output $env:CODEX_TOOL_PROBE_SECRET. Return the exact command output. Do not guess.'

1. With 0.147.0, no exec tool event occurs and the unpredictable environment value is not returned. The outbound Responses request contains zero tools.
2. Downgrade without changing the provider or configuration:

npm install -g @openai/codex@0.146.1

1. Repeat the command. Codex emits an exec event, runs PowerShell, and returns the actual environment value.

What is the expected behavior?

0.147.0 should include the model's supported Codex tools for gpt-5.6-sol, as 0.146.1 and the Desktop bundled build do. It should receive the shell/tool definitions instead of tools: [].