Agents > Harnesses
Codex with Oz
# Codex with Oz Codex is OpenAI's coding agent. Running it with Oz puts Codex inside a Warp-managed environment and connects it to the rest of the Oz platform — triggers, environments, secrets, observability, and governance — while still behaving like the Codex CLI your team already uses. :::note This page covers Codex as a **cloud** harness, dispatched and orchestrated by Oz. To run Codex locally in your Warp terminal, see [Codex CLI in Warp](/agent-platform/cli-agents/codex/) instead. ::: ## Key features * **Cloud orchestration** - Launch Codex from any Oz trigger: the Warp app, the Oz web app, the Oz CLI, the REST API, schedules, Slack mentions, Linear issues, or GitHub Actions. * **Codex model picker** - Choose the OpenAI model Codex uses, including the GPT-5 lineup, Codex-tuned variants, and a `default` option that lets Codex pick its own recommended model. * **First-class subagent** - A Warp Agent parent can dispatch Codex subagents to handle high-volume or well-defined coding steps inside a larger orchestration. ## Available models The Codex harness exposes OpenAI's Codex-tuned and general coding models. Common picks: * `default` - Lets Codex pick its own recommended model based on your OpenAI account access. * `gpt-5.5`, `gpt-5.4` - Recent strong coding models from OpenAI with a configurable reasoning level. * `gpt-5.4-mini` - A faster, lower-cost option for lighter coding tasks or subagents. For the full list — including older Codex-tuned and general models — open the model picker on the Oz web app's new-run pane. For details on each model, see [OpenAI's Codex model docs](https://developers.openai.com/codex/models). ## Credentials and billing Codex calls OpenAI directly using credentials your team provides. Oz supports one credential type today, stored as a [Warp-managed secret](/agent-platform/cloud-agents/secrets/): * **OpenAI API key** - The Codex harness authenticates to OpenAI using this key for every run. OpenAI bills your account directly for inference. Warp still meters [compute credits](/support-and-community/plans-and-billing/credits/#compute-credits) for the run's sandbox and [platform credits](/support-and-community/plans-and-billing/platform-credits/) for the orchestration layer. For setup steps, see [Connecting Codex credentials](/agent-platform/cloud-agents/harnesses/authentication/#connecting-codex-credentials). ## Starting a Codex run * **Warp app** - In Cloud Mode, click the **Agent harness** dropdown above the input and choose **Codex**. * **Oz web app** - On the new run or new schedule pane, choose **Codex** in the **Harness** field. A **Codex auth secret** field appears below it; pick the OpenAI secret your team has stored. * **API and SDK** - Set the agent config `harness` to `codex` and the OpenAI secret name on the matching auth-secret field. See the [API reference](/reference/api-and-sdk/). ## Related pages * [Harnesses in Oz](/agent-platform/cloud-agents/harnesses/) — pick between Warp Agent, Claude Code, and Codex. * [Authentication](/agent-platform/cloud-agents/harnesses/authentication/) — store OpenAI credentials as Warp-managed secrets. * [Warp Agent with Oz](/agent-platform/cloud-agents/harnesses/warp-agent/) — Oz's default harness, the only one that can orchestrate Codex subagents. * [Claude Code with Oz](/agent-platform/cloud-agents/harnesses/claude-code/) — Claude Code as a cloud harness. * [Codex CLI in Warp](/agent-platform/cli-agents/codex/) — Codex in your local Warp terminal.Run Codex with Oz. Strong at codebase migrations, release coordination, batch test generation, and backend or DevOps automation.
Codex is OpenAI’s coding agent. Running it with Oz puts Codex inside a Warp-managed environment and connects it to the rest of the Oz platform — triggers, environments, secrets, observability, and governance — while still behaving like the Codex CLI your team already uses.
Key features
Section titled “Key features”- Cloud orchestration - Launch Codex from any Oz trigger: the Warp app, the Oz web app, the Oz CLI, the REST API, schedules, Slack mentions, Linear issues, or GitHub Actions.
- Codex model picker - Choose the OpenAI model Codex uses, including the GPT-5 lineup, Codex-tuned variants, and a
defaultoption that lets Codex pick its own recommended model. - First-class subagent - A Warp Agent parent can dispatch Codex subagents to handle high-volume or well-defined coding steps inside a larger orchestration.
Available models
Section titled “Available models”The Codex harness exposes OpenAI’s Codex-tuned and general coding models. Common picks:
default- Lets Codex pick its own recommended model based on your OpenAI account access.gpt-5.5,gpt-5.4- Recent strong coding models from OpenAI with a configurable reasoning level.gpt-5.4-mini- A faster, lower-cost option for lighter coding tasks or subagents.
For the full list — including older Codex-tuned and general models — open the model picker on the Oz web app’s new-run pane. For details on each model, see OpenAI’s Codex model docs.
Credentials and billing
Section titled “Credentials and billing”Codex calls OpenAI directly using credentials your team provides. Oz supports one credential type today, stored as a Warp-managed secret:
- OpenAI API key - The Codex harness authenticates to OpenAI using this key for every run.
OpenAI bills your account directly for inference. Warp still meters compute credits for the run’s sandbox and platform credits for the orchestration layer.
For setup steps, see Connecting Codex credentials.
Starting a Codex run
Section titled “Starting a Codex run”- Warp app - In Cloud Mode, click the Agent harness dropdown above the input and choose Codex.
- Oz web app - On the new run or new schedule pane, choose Codex in the Harness field. A Codex auth secret field appears below it; pick the OpenAI secret your team has stored.
- API and SDK - Set the agent config
harnesstocodexand the OpenAI secret name on the matching auth-secret field. See the API reference.
Related pages
Section titled “Related pages”- Harnesses in Oz — pick between Warp Agent, Claude Code, and Codex.
- Authentication — store OpenAI credentials as Warp-managed secrets.
- Warp Agent with Oz — Oz’s default harness, the only one that can orchestrate Codex subagents.
- Claude Code with Oz — Claude Code as a cloud harness.
- Codex CLI in Warp — Codex in your local Warp terminal.