OpenAI Codex CLI

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Q: unsupported parameter: 'reasoning.summary' is not supported with the 'gpt-5.3-codex-spark' model.

reasoning.summary is an optional Responses API field that asks the model to return a summary of its reasoning. Not every reasoning model supports it — this error means the model named in the message does not accept the field, so the request is rejected. Two things are worth checking separately. First, the model id: gpt-5.3-codex-spark is not in the CodeGateway model catalog. The Codex model we serve is gpt-5.3-codex, and it is Responses-API-only — send it to POST /v1/responses, not to /v1/chat/completions. If you call CodeGateway with the model still set to gpt-5.3-codex-spark, you get a 400 Unsupported model response instead, which is how you can tell the two failures apart. Second, the parameter: drop reasoning.summary from the request body. The field is optional, and requests that omit it are unaffected. If you need reasoning summaries, check the target model's own API reference first — availability differs by model and snapshot. When a tool adds the field for you, look for the corresponding reasoning or summary option in its configuration and turn it off, or switch to a model whose reference documents reasoning summaries.

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Codex CLI install & config.toml

Two install commands plus the config.toml keys you must set — full guide covers MCP and errors.

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winget install OpenAI.Codex

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npm install -g @openai/codex

Why connect Codex CLI through CodeGateway?

Codex CLI connects to OpenAI by default. If you want pay-as-you-go pricing and one key for every model — CodeGateway can be the backend.

Cheaper

Pay-as-you-go at official price × service markup. No hidden fees. Flat 1.07× consumption markup; top-ups add a 2% service fee. No monthly fee, no minimum top-up.

Stable Access

Requests are routed through Cloudflare's global edge, which keeps cross-border connections steadier and usually lower-latency than connecting directly. Availability of some models is limited by upstream regional policy — see the note below.

Codex CLI error FAQ

The only Codex CLI error query with 30+ GSC impressions, one step off page one

unsupported parameter: 'reasoning.summary' is not supported with the 'gpt-5.3-codex-spark' model.

reasoning.summary is an optional Responses API field that asks the model to return a summary of its reasoning. Not every reasoning model supports it — this error means the model named in the message does not accept the field, so the request is rejected.

Two things are worth checking separately. First, the model id: gpt-5.3-codex-spark is not in the CodeGateway model catalog. The Codex model we serve is gpt-5.3-codex, and it is Responses-API-only — send it to POST /v1/responses, not to /v1/chat/completions. If you call CodeGateway with the model still set to gpt-5.3-codex-spark, you get a 400 Unsupported model response instead, which is how you can tell the two failures apart.

Second, the parameter: drop reasoning.summary from the request body. The field is optional, and requests that omit it are unaffected. If you need reasoning summaries, check the target model's own API reference first — availability differs by model and snapshot. When a tool adds the field for you, look for the corresponding reasoning or summary option in its configuration and turn it off, or switch to a model whose reference documents reasoning summaries.